diff --git a/.gitignore b/.gitignore
index 7d9c0e4..d1a0b92 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,6 +6,7 @@ xcuserdata
 !src/**/build/
 local.properties
 .idea
+**/network_security_config.xml
 .DS_Store
 captures
 .externalNativeBuild
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/App.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/App.kt
index 6607201..c8e7b3c 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/App.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/App.kt
@@ -3,12 +3,15 @@ package org.whosin.client
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.statusBarsPadding
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
 import androidx.navigation.compose.rememberNavController
 import org.jetbrains.compose.ui.tooling.preview.Preview
+import org.whosin.client.core.auth.TokenExpiredManager
+import org.whosin.client.core.navigation.Route
 import org.whosin.client.core.navigation.WhosInNavGraph
-import org.whosin.client.presentation.dummy.DummyScreen
-import org.whosin.client.presentation.dummy.TokenTestScreen
 import ui.theme.WhosInTheme
 
 
@@ -17,6 +20,16 @@ import ui.theme.WhosInTheme
 fun App() {
     WhosInTheme {
         val navController = rememberNavController()
+        val isTokenExpired by TokenExpiredManager.isTokenExpired.collectAsState()
+
+        LaunchedEffect(isTokenExpired) {
+            if (isTokenExpired) {
+                navController.navigate(Route.Login) {
+                    popUpTo(0) { inclusive = true }
+                }
+                TokenExpiredManager.reset()
+            }
+        }
 
         WhosInNavGraph(
             modifier = Modifier
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/core/auth/TokenExpiredManager.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/core/auth/TokenExpiredManager.kt
new file mode 100644
index 0000000..234deba
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/core/auth/TokenExpiredManager.kt
@@ -0,0 +1,18 @@
+package org.whosin.client.core.auth
+
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+object TokenExpiredManager {
+    private val _isTokenExpired = MutableStateFlow(false)
+    val isTokenExpired: StateFlow<Boolean> = _isTokenExpired.asStateFlow()
+
+    fun setTokenExpired() {
+        _isTokenExpired.value = true
+    }
+
+    fun reset() {
+        _isTokenExpired.value = false
+    }
+}
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/core/navigation/Route.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/core/navigation/Route.kt
index 904417f..7ef462f 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/core/navigation/Route.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/core/navigation/Route.kt
@@ -20,13 +20,13 @@ sealed interface Route {
     data object Signup: Route
 
     @Serializable
-    data object EmailVerification: Route
+    data class EmailVerification(val email: String): Route
 
     @Serializable
-    data object PasswordInput: Route
+    data class PasswordInput(val email: String): Route
 
     @Serializable
-    data object NicknameInput: Route
+    data class NicknameInput(val email: String, val password: String): Route
 
     @Serializable
     data class ClubCodeInput(val returnToMyPage: Boolean = false): Route
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/core/navigation/WhosInNavGraph.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/core/navigation/WhosInNavGraph.kt
index e7698a3..70fa078 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/core/navigation/WhosInNavGraph.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/core/navigation/WhosInNavGraph.kt
@@ -38,6 +38,11 @@ fun WhosInNavGraph(
                         navController.navigate(Route.Login) {
                             popUpTo(Route.Splash) { inclusive = true }
                         }
+                    },
+                    onNavigateToHome = {
+                        navController.navigate(Route.Home) {
+                            popUpTo(Route.AuthGraph) { inclusive = true }
+                        }
                     }
                 )
             }
@@ -74,35 +79,43 @@ fun WhosInNavGraph(
                     modifier = modifier,
                     onNavigateBack = { navController.navigateUp() },
                     onNavigateToEmailVerification = { email ->
-                        navController.navigate(Route.EmailVerification)
+                        navController.navigate(Route.EmailVerification(email))
                     }
                 )
             }
             
             composable<Route.EmailVerification> { backStackEntry ->
-                
+                val emailVerificationRoute = backStackEntry.toRoute<Route.EmailVerification>()
+
                 EmailVerificationScreen(
                     modifier = modifier,
+                    email = emailVerificationRoute.email,
                     onNavigateBack = { navController.navigateUp() },
                     onVerificationComplete = {
-                        navController.navigate(Route.PasswordInput)
+                        navController.navigate(Route.PasswordInput(emailVerificationRoute.email))
                     }
                 )
             }
-            
-            composable<Route.PasswordInput> {
+
+            composable<Route.PasswordInput> { backStackEntry ->
+                val passwordInputRoute = backStackEntry.toRoute<Route.PasswordInput>()
+
                 PasswordInputScreen(
                     modifier = modifier,
                     onNavigateBack = { navController.navigateUp() },
                     onPasswordComplete = { password, confirmPassword ->
-                        navController.navigate(Route.NicknameInput)
+                        navController.navigate(Route.NicknameInput(passwordInputRoute.email, password))
                     }
                 )
             }
-            
-            composable<Route.NicknameInput> {
+
+            composable<Route.NicknameInput> { backStackEntry ->
+                val nicknameInputRoute = backStackEntry.toRoute<Route.NicknameInput>()
+
                 NicknameInputScreen(
                     modifier = modifier,
+                    email = nicknameInputRoute.email,
+                    password = nicknameInputRoute.password,
                     onNavigateBack = { navController.navigateUp() },
                     onNavigateToClubCode = {
                         navController.navigate(Route.ClubCodeInput(returnToMyPage = false))
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/core/network/HttpClientFactory.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/core/network/HttpClientFactory.kt
index 2191610..66370ab 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/core/network/HttpClientFactory.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/core/network/HttpClientFactory.kt
@@ -21,9 +21,10 @@ import io.ktor.http.encodedPath
 import io.ktor.serialization.kotlinx.json.json
 import kotlinx.serialization.json.Json
 import org.whosin.client.BuildKonfig
+import org.whosin.client.core.auth.TokenExpiredManager
 import org.whosin.client.core.datastore.TokenManager
 import org.whosin.client.data.dto.request.ReissueTokenRequestDto
-import org.whosin.client.data.dto.response.TokenDto
+import org.whosin.client.data.dto.response.ReissueTokenResponseDto
 
 object HttpClientFactory {
     val BASE_URL = BuildKonfig.BASE_URL
@@ -45,10 +46,11 @@ object HttpClientFactory {
                 socketTimeoutMillis = 20_000L
                 requestTimeoutMillis = 20_000L
             }
-            install(Auth){
+            install(Auth) {
                 bearer {
                     loadTokens {
-                        val accessToken = tokenManager.getAccessToken() ?: "eyJhbGciOiJIUzI1NiJ9.eyJ0b2tlblR5cGUiOiJhY2Nlc3MiLCJ1c2VySWQiOjUsInByb3ZpZGVySWQiOiJsb2NhbGhvc3QiLCJuYW1lIjoi7Iug7KKF7JykIiwicm9sZSI6IlJPTEVfTUVNQkVSIiwiaWF0IjoxNzU5MzgyMzg3LCJleHAiOjE3NTk5ODcxODd9.kT9IH60aCA-6ByEITb-_qPAJY0Oik1bbPKqcBWXzHIk"
+                        val accessToken = tokenManager.getAccessToken()
+                            ?: "eyJhbGciOiJIUzI1NiJ9.eyJ0b2tlblR5cGUiOiJhY2Nlc3MiLCJ1c2VySWQiOjUsInByb3ZpZGVySWQiOiJsb2NhbGhvc3QiLCJuYW1lIjoi7Iug7KKF7JykIiwicm9sZSI6IlJPTEVfTUVNQkVSIiwiaWF0IjoxNzU5MzgyMzg3LCJleHAiOjE3NTk5ODcxODd9.kT9IH60aCA-6ByEITb-_qPAJY0Oik1bbPKqcBWXzHIk"
                         val refreshToken = tokenManager.getRefreshToken() ?: "no_token"
                         BearerTokens(accessToken = accessToken, refreshToken = refreshToken)
                     }
@@ -75,7 +77,7 @@ object HttpClientFactory {
                                 "auth/login",
                                 "auth/email",
                                 "auth/email/validation",
-                                "member/reissue" // 토큰 재발급 요청 자체에는 만료된 액세스 토큰을 보내면 안 됨
+                                "auth/reissue" // 토큰 재발급 요청
                             )
 
                             val isNoAuthPath = pathWithNoAuth.any { noAuthPath ->
@@ -88,26 +90,42 @@ object HttpClientFactory {
                         }
                     }
                     refreshTokens {
-                        val rt = tokenManager.getRefreshToken() ?: "no_token"
-                        val response = client.post("member/reissue"){
-                            setBody {
-                                ReissueTokenRequestDto(
-                                    refreshToken = rt
+                        try {
+                            val rt = tokenManager.getRefreshToken()
+                            if (rt.isNullOrEmpty()) {
+                                tokenManager.clearToken()
+                                TokenExpiredManager.setTokenExpired()
+                                return@refreshTokens null
+                            }
+
+                            val response = client.post("auth/reissue") {
+                                setBody(ReissueTokenRequestDto(refreshToken = rt))
+                                markAsRefreshTokenRequest()
+                            }.body<ReissueTokenResponseDto>()
+
+                            if (response.success && response.data != null) {
+                                tokenManager.saveTokens(
+                                    accessToken = response.data.accessToken,
+                                    refreshToken = response.data.refreshToken
+                                )
+                                BearerTokens(
+                                    accessToken = response.data.accessToken,
+                                    refreshToken = response.data.refreshToken
                                 )
+                            } else {
+                                tokenManager.clearToken()
+                                TokenExpiredManager.setTokenExpired()
+                                null
                             }
-                            markAsRefreshTokenRequest()
-                        }.body<TokenDto>()
-                        tokenManager.saveTokens(
-                            accessToken = response.accessToken,
-                            refreshToken = response.refreshToken
-                        )
-                        val accessToken = response.accessToken
-                        val refreshToken = response.refreshToken
-                        BearerTokens(accessToken,refreshToken)
+                        } catch (e: Exception) {
+                            tokenManager.clearToken()
+                            TokenExpiredManager.setTokenExpired()
+                            null
+                        }
                     }
                 }
             }
-            install(Logging){
+            install(Logging) {
                 logger = object : Logger {
                     override fun log(message: String) {
                         println(message)
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/request/EmailValidationRequestDto.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/request/EmailValidationRequestDto.kt
new file mode 100644
index 0000000..da9e46e
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/request/EmailValidationRequestDto.kt
@@ -0,0 +1,12 @@
+package org.whosin.client.data.dto.request
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class EmailValidationRequestDto(
+    @SerialName("email")
+    val email: String,
+    @SerialName("authCode")
+    val authCode: String
+)
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/request/EmailVerificationRequestDto.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/request/EmailVerificationRequestDto.kt
new file mode 100644
index 0000000..95bd139
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/request/EmailVerificationRequestDto.kt
@@ -0,0 +1,10 @@
+package org.whosin.client.data.dto.request
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class EmailVerificationRequestDto(
+    @SerialName("email")
+    val email: String
+)
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/request/FindPasswordRequestDto.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/request/FindPasswordRequestDto.kt
new file mode 100644
index 0000000..baf530a
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/request/FindPasswordRequestDto.kt
@@ -0,0 +1,10 @@
+package org.whosin.client.data.dto.request
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class FindPasswordRequestDto(
+    @SerialName("email")
+    val email: String
+)
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/request/SignupRequestDto.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/request/SignupRequestDto.kt
new file mode 100644
index 0000000..9d7dedf
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/request/SignupRequestDto.kt
@@ -0,0 +1,14 @@
+package org.whosin.client.data.dto.request
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class SignupRequestDto(
+    @SerialName("email")
+    val email: String,
+    @SerialName("password")
+    val password: String,
+    @SerialName("nickName")
+    val nickName: String
+)
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/EmailVerificationResponseDto.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/EmailVerificationResponseDto.kt
new file mode 100644
index 0000000..3643894
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/EmailVerificationResponseDto.kt
@@ -0,0 +1,18 @@
+package org.whosin.client.data.dto.response
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class EmailVerificationResponseDto(
+    @SerialName("success")
+    val success: Boolean,
+    @SerialName("status")
+    val status: Int,
+    @SerialName("message")
+    val message: String,
+    @SerialName("data")
+    val data: String? = null,
+    @SerialName("timestamp")
+    val timestamp: String? = null
+)
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/FindPasswordResponseDto.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/FindPasswordResponseDto.kt
new file mode 100644
index 0000000..74ec48b
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/FindPasswordResponseDto.kt
@@ -0,0 +1,18 @@
+package org.whosin.client.data.dto.response
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class FindPasswordResponseDto(
+    @SerialName("success")
+    val success: Boolean,
+    @SerialName("status")
+    val status: Int,
+    @SerialName("message")
+    val message: String,
+    @SerialName("data")
+    val data: String? = null,
+    @SerialName("timestamp")
+    val timestamp: String? = null
+)
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/LoginResponseDto.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/LoginResponseDto.kt
index 9149800..59171ef 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/LoginResponseDto.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/LoginResponseDto.kt
@@ -7,12 +7,14 @@ import kotlinx.serialization.Serializable
 data class LoginResponseDto(
     @SerialName("success")
     val success: Boolean,
-    @SerialName("code")
-    val code: Int,
+    @SerialName("status")
+    val status: Int,
     @SerialName("message")
     val message: String,
     @SerialName("data")
-    val data: TokenDto
+    val data: TokenDto? = null,
+    @SerialName("timestamp")
+    val timestamp: String? = null
 )
 
 @Serializable
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/ReissueTokenResponseDto.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/ReissueTokenResponseDto.kt
new file mode 100644
index 0000000..9bcb7d3
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/ReissueTokenResponseDto.kt
@@ -0,0 +1,18 @@
+package org.whosin.client.data.dto.response
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class ReissueTokenResponseDto(
+    @SerialName("success")
+    val success: Boolean,
+    @SerialName("status")
+    val status: Int,
+    @SerialName("message")
+    val message: String,
+    @SerialName("data")
+    val data: TokenDto? = null,
+    @SerialName("timestamp")
+    val timestamp: String? = null
+)
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/SignupResponseDto.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/SignupResponseDto.kt
new file mode 100644
index 0000000..be3e21d
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/dto/response/SignupResponseDto.kt
@@ -0,0 +1,18 @@
+package org.whosin.client.data.dto.response
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class SignupResponseDto(
+    @SerialName("success")
+    val success: Boolean,
+    @SerialName("status")
+    val status: Int,
+    @SerialName("message")
+    val message: String,
+    @SerialName("data")
+    val data: String? = null,
+    @SerialName("timestamp")
+    val timestamp: String? = null
+)
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/remote/RemoteAuthDataSource.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/remote/RemoteAuthDataSource.kt
new file mode 100644
index 0000000..a72ae98
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/remote/RemoteAuthDataSource.kt
@@ -0,0 +1,164 @@
+package org.whosin.client.data.remote
+
+import io.ktor.client.HttpClient
+import io.ktor.client.call.body
+import io.ktor.client.request.post
+import io.ktor.client.request.setBody
+import io.ktor.client.statement.HttpResponse
+import io.ktor.http.isSuccess
+import org.whosin.client.core.network.ApiResult
+import org.whosin.client.data.dto.request.EmailValidationRequestDto
+import org.whosin.client.data.dto.request.EmailVerificationRequestDto
+import org.whosin.client.data.dto.request.FindPasswordRequestDto
+import org.whosin.client.data.dto.request.LoginRequestDto
+import org.whosin.client.data.dto.request.SignupRequestDto
+import org.whosin.client.data.dto.response.EmailVerificationResponseDto
+import org.whosin.client.data.dto.response.ErrorResponseDto
+import org.whosin.client.data.dto.response.FindPasswordResponseDto
+import org.whosin.client.data.dto.response.LoginResponseDto
+import org.whosin.client.data.dto.response.SignupResponseDto
+
+class RemoteAuthDataSource(
+    private val client: HttpClient
+) {
+    suspend fun login(email: String, password: String): ApiResult<LoginResponseDto> {
+        return try {
+            val response: HttpResponse = client
+                .post("auth/login") {
+                    setBody(
+                        LoginRequestDto(email = email, password = password)
+                    )
+                }
+            if (response.status.isSuccess()) {
+                ApiResult.Success(
+                    data = response.body(),
+                    statusCode = response.status.value
+                )
+            } else {
+                // 에러 응답 파싱 시도
+                try {
+                    val errorResponse: ErrorResponseDto = response.body()
+                    ApiResult.Error(
+                        code = response.status.value,
+                        message = errorResponse.message
+                    )
+                } catch (e: Exception) {
+                    // 파싱 실패 시 기본 에러 메시지
+                    ApiResult.Error(
+                        code = response.status.value,
+                        message = "HTTP Error: ${response.status.value}"
+                    )
+                }
+            }
+        } catch (t: Throwable) {
+            ApiResult.Error(message = t.message, cause = t)
+        }
+    }
+
+    suspend fun sendEmailVerification(email: String): ApiResult<EmailVerificationResponseDto> {
+        return try {
+            val response: HttpResponse = client
+                .post("auth/email/send") {
+                    setBody(
+                        EmailVerificationRequestDto(email = email)
+                    )
+                }
+            if (response.status.isSuccess()) {
+                ApiResult.Success(
+                    data = response.body(),
+                    statusCode = response.status.value
+                )
+            } else {
+                val errorResponse: EmailVerificationResponseDto = response.body()
+                ApiResult.Error(
+                    code = errorResponse.status,
+                    message = errorResponse.message
+                )
+            }
+        } catch (t: Throwable) {
+            ApiResult.Error(message = t.message, cause = t)
+        }
+    }
+
+    suspend fun validateEmailCode(
+        email: String,
+        authCode: String
+    ): ApiResult<EmailVerificationResponseDto> {
+        return try {
+            val response: HttpResponse = client
+                .post("auth/email/validation") {
+                    setBody(
+                        EmailValidationRequestDto(email = email, authCode = authCode)
+                    )
+                }
+            if (response.status.isSuccess()) {
+                ApiResult.Success(
+                    data = response.body(),
+                    statusCode = response.status.value
+                )
+            } else {
+                val errorResponse: EmailVerificationResponseDto = response.body()
+                ApiResult.Error(
+                    code = errorResponse.status,
+                    message = errorResponse.message
+                )
+            }
+        } catch (t: Throwable) {
+            ApiResult.Error(message = t.message, cause = t)
+        }
+    }
+
+    suspend fun signup(
+        email: String,
+        password: String,
+        nickName: String
+    ): ApiResult<SignupResponseDto> {
+        return try {
+            val response: HttpResponse = client
+                .post("users/signup") {
+                    setBody(
+                        SignupRequestDto(email = email, password = password, nickName = nickName)
+                    )
+                }
+            if (response.status.isSuccess()) {
+                ApiResult.Success(
+                    data = response.body(),
+                    statusCode = response.status.value
+                )
+            } else {
+                val errorResponse: SignupResponseDto = response.body()
+                ApiResult.Error(
+                    code = errorResponse.status,
+                    message = errorResponse.message
+                )
+            }
+        } catch (t: Throwable) {
+            ApiResult.Error(message = t.message, cause = t)
+        }
+    }
+
+    suspend fun sendPasswordResetEmail(email: String): ApiResult<FindPasswordResponseDto> {
+        return try {
+            val response: HttpResponse = client
+                .post("auth/email/find-password") {
+                    setBody(
+                        FindPasswordRequestDto(email = email)
+                    )
+                }
+            if (response.status.isSuccess()) {
+                ApiResult.Success(
+                    data = response.body(),
+                    statusCode = response.status.value
+                )
+            } else {
+                val errorResponse: FindPasswordResponseDto = response.body()
+                ApiResult.Error(
+                    code = errorResponse.status,
+                    message = errorResponse.message
+                )
+            }
+        } catch (t: Throwable) {
+            ApiResult.Error(message = t.message, cause = t)
+        }
+    }
+}
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/remote/RemoteMemberDataSource.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/remote/RemoteMemberDataSource.kt
index aa47518..21c67cf 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/data/remote/RemoteMemberDataSource.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/remote/RemoteMemberDataSource.kt
@@ -4,46 +4,18 @@ import io.ktor.client.HttpClient
 import io.ktor.client.call.body
 import io.ktor.client.request.get
 import io.ktor.client.request.patch
-import io.ktor.client.request.post
 import io.ktor.client.request.setBody
 import io.ktor.client.statement.HttpResponse
 import io.ktor.http.isSuccess
 import org.whosin.client.core.network.ApiResult
-import org.whosin.client.data.dto.request.LoginRequestDto
 import org.whosin.client.data.dto.request.UpdateMyInfoRequestDto
 import org.whosin.client.data.dto.response.ErrorResponseDto
-import org.whosin.client.data.dto.response.LoginResponseDto
 import org.whosin.client.data.dto.response.MyInfoResponseDto
 import org.whosin.client.data.dto.response.UpdateMyInfoResponseDto
 
 class RemoteMemberDataSource(
     private val client: HttpClient
 ) {
-    suspend fun login(email: String, password: String): ApiResult<LoginResponseDto> {
-        return try {
-            val response: HttpResponse = client
-                // TODO: BaseUrl 가져올 수 있도록 처리
-                .post(urlString = "BASEURL/members/login") {
-                    setBody(
-                        LoginRequestDto(email = email, password = password)
-                    )
-                }
-            if (response.status.isSuccess()) {
-                ApiResult.Success(
-                    data = response.body(),
-                    statusCode = response.status.value
-                )
-            } else {
-                ApiResult.Error(
-                    code = response.status.value,
-                    message = "HTTP ${response.status.value}"
-                )
-            }
-        } catch (t: Throwable) {
-            ApiResult.Error(message = t.message, cause = t)
-        }
-    }
-
     // 내 정보 조회
     suspend fun getMyInfo(): ApiResult<MyInfoResponseDto> {
         return try {
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/repository/AuthRepository.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/repository/AuthRepository.kt
new file mode 100644
index 0000000..0d8c97f
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/repository/AuthRepository.kt
@@ -0,0 +1,40 @@
+package org.whosin.client.data.repository
+
+import org.whosin.client.data.remote.RemoteAuthDataSource
+import org.whosin.client.core.network.ApiResult
+import org.whosin.client.data.dto.response.LoginResponseDto
+import org.whosin.client.data.dto.response.EmailVerificationResponseDto
+import org.whosin.client.data.dto.response.SignupResponseDto
+import org.whosin.client.data.dto.response.FindPasswordResponseDto
+
+class AuthRepository(
+    private val dataSource: RemoteAuthDataSource
+) {
+    suspend fun login(
+        email: String,
+        password: String
+    ): ApiResult<LoginResponseDto> =
+        dataSource.login(email, password)
+
+    suspend fun sendEmailVerification(
+        email: String
+    ): ApiResult<EmailVerificationResponseDto> =
+        dataSource.sendEmailVerification(email)
+
+    suspend fun validateEmailCode(
+        email: String,
+        authCode: String
+    ): ApiResult<EmailVerificationResponseDto> =
+        dataSource.validateEmailCode(email, authCode)
+
+    suspend fun signup(
+        email: String,
+        password: String,
+        nickName: String
+    ): ApiResult<SignupResponseDto> =
+        dataSource.signup(email, password, nickName)
+
+    suspend fun sendPasswordResetEmail(email: String): ApiResult<FindPasswordResponseDto> =
+        dataSource.sendPasswordResetEmail(email)
+
+}
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/data/repository/MemberRepository.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/data/repository/MemberRepository.kt
index 6ccbffe..455cb10 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/data/repository/MemberRepository.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/data/repository/MemberRepository.kt
@@ -2,20 +2,15 @@ package org.whosin.client.data.repository
 
 import org.whosin.client.data.remote.RemoteMemberDataSource
 import org.whosin.client.core.network.ApiResult
-import org.whosin.client.data.dto.response.LoginResponseDto
 import org.whosin.client.data.dto.response.MyInfoResponseDto
 import org.whosin.client.data.dto.response.UpdateMyInfoResponseDto
 
 class MemberRepository(
     private val dataSource: RemoteMemberDataSource
 ) {
-    suspend fun login(email: String, password: String): ApiResult<LoginResponseDto> =
-        dataSource.login(email, password)
-
     suspend fun getMyInfo(): ApiResult<MyInfoResponseDto> =
         dataSource.getMyInfo()
 
     suspend fun updateMyInfo(newNickName: String, clubList: List<Int>?): ApiResult<UpdateMyInfoResponseDto> =
         dataSource.updateMyInfo(newNickName = newNickName, clubList = clubList)
-
 }
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/di/DIModules.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/di/DIModules.kt
index 4838b27..992cc06 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/di/DIModules.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/di/DIModules.kt
@@ -5,15 +5,20 @@ import org.koin.core.module.dsl.viewModelOf
 import org.koin.dsl.module
 import org.whosin.client.core.network.HttpClientFactory
 import org.whosin.client.data.remote.DummyDataSource
+import org.whosin.client.data.remote.RemoteAuthDataSource
 import org.whosin.client.data.remote.RemoteClubDataSource
 import org.whosin.client.data.remote.RemoteMemberDataSource
+import org.whosin.client.data.repository.AuthRepository
 import org.whosin.client.data.repository.DummyRepository
 import org.whosin.client.data.repository.ClubRepository
 import org.whosin.client.data.repository.MemberRepository
 import org.whosin.client.presentation.auth.clubcode.AddClubViewModel
 import org.whosin.client.presentation.dummy.DummyViewModel
 import org.whosin.client.presentation.dummy.TokenTestViewModel
+import org.whosin.client.presentation.auth.login.viewmodel.FindPasswordViewModel
 import org.whosin.client.presentation.auth.login.viewmodel.LoginViewModel
+import org.whosin.client.presentation.auth.login.viewmodel.SignupViewModel
+import org.whosin.client.presentation.auth.login.viewmodel.SplashViewModel
 import org.whosin.client.presentation.home.HomeViewModel
 import org.whosin.client.presentation.mypage.MyPageViewModel
 
@@ -32,12 +37,14 @@ val httpClientModule = module {
 }
 
 val dataSourceModule = module {
+    single { RemoteAuthDataSource(get()) }
     single { RemoteMemberDataSource(get()) }
     single { RemoteClubDataSource(get()) }
     single { DummyDataSource(get()) } // TODO: 이후에 삭제 예정
 }
 
 val repositoryModule = module {
+    single { AuthRepository(get()) }
     single { MemberRepository(get()) }
     single { ClubRepository(get()) }
     single { DummyRepository(get()) } // TODO: 이후에 삭제 예정
@@ -45,7 +52,10 @@ val repositoryModule = module {
 
 // ViewModel을 새로 생성하는 경우에 모듈에 추가하여 사용
 val viewModelModule = module {
+    viewModelOf(::SplashViewModel)
     viewModelOf(::LoginViewModel)
+    viewModelOf(::SignupViewModel)
+    viewModelOf(::FindPasswordViewModel)
     viewModelOf(::HomeViewModel)
     viewModelOf(::MyPageViewModel)
     viewModelOf(::DummyViewModel) // TODO: 이후에 삭제 예정
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/clubcode/ClubCodeInputScreen.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/clubcode/ClubCodeInputScreen.kt
index 037e787..f013866 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/clubcode/ClubCodeInputScreen.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/clubcode/ClubCodeInputScreen.kt
@@ -152,16 +152,20 @@ fun ClubCodeInputScreen(
                         onValueChange = { input ->
                             if (input.length <= 1 && input.all { it.isDigit() }) {
                                 val newCode = clubCode.copyOf()
-                                val wasEmpty = clubCode[index].isEmpty()
                                 newCode[index] = input
                                 clubCode = newCode
 
+                                // 숫자를 입력했을 때만 다음 박스로 이동
                                 if (input.isNotEmpty() && index < 5) {
                                     currentFocusIndex = index + 1
                                     focusRequesters[index + 1].requestFocus()
-                                } else if (input.isEmpty() && !wasEmpty && index > 0) {
+                                    keyboardController?.show()
+                                }
+                                // 현재 박스가 비워지고 이전 박스가 있으면 이전으로 이동
+                                else if (input.isEmpty() && index > 0) {
                                     currentFocusIndex = index - 1
                                     focusRequesters[index - 1].requestFocus()
+                                    keyboardController?.show()
                                 }
                             }
                         },
@@ -170,6 +174,7 @@ fun ClubCodeInputScreen(
                                 val prevIndex = index - 1
                                 currentFocusIndex = prevIndex
                                 focusRequesters[prevIndex].requestFocus()
+                                keyboardController?.show()
                             }
                         },
                         onFocusChanged = { isFocused ->
@@ -177,6 +182,11 @@ fun ClubCodeInputScreen(
                                 currentFocusIndex = index
                             }
                         },
+                        onClick = {
+                            currentFocusIndex = index
+                            focusRequesters[index].requestFocus()
+                            keyboardController?.show()
+                        },
                         borderColor = when (currentState) {
                             ClubCodeState.ERROR -> Color(0xFFFF3636)
                             else -> Color(0xFFE5E5E5)
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/EmailVerificationScreen.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/EmailVerificationScreen.kt
index 812e382..a41d95d 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/EmailVerificationScreen.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/EmailVerificationScreen.kt
@@ -9,6 +9,7 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
@@ -17,6 +18,7 @@ import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
@@ -25,12 +27,17 @@ import androidx.compose.ui.focus.focusRequester
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.platform.LocalSoftwareKeyboardController
 import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
-import kotlinx.coroutines.delay
 import coil3.compose.AsyncImage
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
 import org.jetbrains.compose.resources.stringResource
 import org.jetbrains.compose.ui.tooling.preview.Preview
+import org.koin.compose.koinInject
+import org.whosin.client.core.network.ApiResult
+import org.whosin.client.data.repository.AuthRepository
 import org.whosin.client.presentation.auth.login.component.CommonLoginButton
 import org.whosin.client.presentation.auth.login.component.NumberInputBox
 import whosinclient.composeapp.generated.resources.Res
@@ -41,14 +48,20 @@ import whosinclient.composeapp.generated.resources.email_verification_title
 @Composable
 fun EmailVerificationScreen(
     modifier: Modifier = Modifier,
+    email: String = "",
     onNavigateBack: () -> Unit = {},
-    onVerificationComplete: (String) -> Unit = {}
+    onVerificationComplete: () -> Unit = {}
 ) {
     var verificationCode by remember { mutableStateOf(arrayOf("", "", "", "", "", "")) }
     var currentFocusIndex by remember { mutableStateOf(0) }
+    var isLoading by remember { mutableStateOf(false) }
+    var errorMessage by remember { mutableStateOf<String?>(null) }
     val focusRequesters = remember { List(6) { FocusRequester() } }
     val keyboardController = LocalSoftwareKeyboardController.current
 
+    val authRepository: AuthRepository = koinInject()
+    val coroutineScope = rememberCoroutineScope()
+
     // 화면 진입 시 첫 번째 입력 박스에 포커스
     LaunchedEffect(Unit) {
         delay(300)
@@ -110,18 +123,21 @@ fun EmailVerificationScreen(
                         onValueChange = { input ->
                             if (input.length <= 1 && input.all { it.isDigit() }) {
                                 val newCode = verificationCode.copyOf()
-                                val wasEmpty = verificationCode[index].isEmpty()
                                 newCode[index] = input
                                 verificationCode = newCode
 
+                                // 에러 메시지 초기화
+                                errorMessage = null
+
+                                // 숫자를 입력했을 때만 다음 박스로 이동
                                 if (input.isNotEmpty() && index < 5) {
                                     currentFocusIndex = index + 1
                                     focusRequesters[index + 1].requestFocus()
-                                } else if (input.isEmpty() && !wasEmpty && index > 0) {
+                                }
+                                // 현재 박스가 비워지고 이전 박스가 있으면 이전으로 이동
+                                else if (input.isEmpty() && index > 0) {
                                     currentFocusIndex = index - 1
                                     focusRequesters[index - 1].requestFocus()
-                                } else if (input.isNotEmpty()) {
-                                    currentFocusIndex = index
                                 }
                             }
                         },
@@ -138,6 +154,11 @@ fun EmailVerificationScreen(
                                 currentFocusIndex = index
                             }
                         },
+                        onClick = {
+                            currentFocusIndex = index
+                            focusRequesters[index].requestFocus()
+                            keyboardController?.show()
+                        },
                         isFocused = currentFocusIndex == index,
                         modifier = Modifier
                             .weight(1f)
@@ -145,18 +166,60 @@ fun EmailVerificationScreen(
                     )
                 }
             }
+
+            // 에러 메시지 표시
+            if (errorMessage != null) {
+                Text(
+                    text = errorMessage!!,
+                    color = Color(0xFFFF3636),
+                    fontSize = 14.sp,
+                    fontWeight = FontWeight.W500,
+                    textAlign = TextAlign.Center,
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .padding(top = 16.dp)
+                )
+            }
         }
 
         // 하단 확인 버튼
         CommonLoginButton(
             text = stringResource(Res.string.confirm_button),
-            onClick = { onVerificationComplete(fullCode) },
-            enabled = isComplete,
+            onClick = {
+                if (isComplete && !isLoading) {
+                    isLoading = true
+
+                    coroutineScope.launch {
+                        when (val result = authRepository.validateEmailCode(email, fullCode)) {
+                            is ApiResult.Success<*> -> {
+                                isLoading = false
+                                onVerificationComplete()
+                            }
+
+                            is ApiResult.Error -> {
+                                isLoading = false
+                                errorMessage = result.message
+                            }
+                        }
+                    }
+                }
+            },
+            enabled = isComplete && !isLoading,
             modifier = Modifier
                 .align(Alignment.BottomCenter)
                 .padding(horizontal = 16.dp)
                 .padding(bottom = 52.dp)
         )
+
+        // 로딩 인디케이터
+        if (isLoading) {
+            CircularProgressIndicator(
+                color = Color(0xFFF89531),
+                modifier = Modifier
+                    .align(Alignment.Center)
+                    .size(48.dp)
+            )
+        }
     }
 }
 
@@ -165,8 +228,9 @@ fun EmailVerificationScreen(
 fun VerificationCodeScreenPreview() {
     EmailVerificationScreen(
         modifier = Modifier,
+        email = "test@example.com",
         onNavigateBack = {},
-        onVerificationComplete = { code ->
+        onVerificationComplete = {
             // 인증번호 처리 로직
         }
     )
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/FindPasswordScreen.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/FindPasswordScreen.kt
index 73146bd..b98b6c2 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/FindPasswordScreen.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/FindPasswordScreen.kt
@@ -8,8 +8,11 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.material3.IconButton
+import androidx.compose.material3.Snackbar
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -21,10 +24,14 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import coil3.compose.AsyncImage
+import kotlinx.coroutines.delay
 import org.jetbrains.compose.resources.stringResource
 import org.jetbrains.compose.ui.tooling.preview.Preview
+import org.koin.compose.viewmodel.koinViewModel
 import org.whosin.client.presentation.auth.login.component.CommonLoginButton
 import org.whosin.client.presentation.auth.login.component.CommonLoginInputField
+import org.whosin.client.presentation.auth.login.viewmodel.FindPasswordUiState
+import org.whosin.client.presentation.auth.login.viewmodel.FindPasswordViewModel
 import whosinclient.composeapp.generated.resources.Res
 import whosinclient.composeapp.generated.resources.back_button
 import whosinclient.composeapp.generated.resources.email_placeholder
@@ -35,9 +42,23 @@ import whosinclient.composeapp.generated.resources.send_email_button
 fun FindPasswordScreen(
     modifier: Modifier = Modifier,
     onNavigateBack: () -> Unit = {},
-    onPasswordResetComplete: (String) -> Unit = {}
+    onPasswordResetComplete: () -> Unit = {},
+    viewModel: FindPasswordViewModel = koinViewModel()
 ) {
     var email by remember { mutableStateOf("") }
+    var showSuccessToast by remember { mutableStateOf(false) }
+    val uiState by viewModel.uiState.collectAsState()
+
+    LaunchedEffect(uiState) {
+        when (uiState) {
+            is FindPasswordUiState.Success -> {
+                showSuccessToast = true
+                delay(2000) // 2초 후 로그인 화면으로 이동
+                onPasswordResetComplete()
+            }
+            else -> {}
+        }
+    }
 
     Box(
         modifier = modifier
@@ -81,13 +102,33 @@ fun FindPasswordScreen(
 
         CommonLoginButton(
             text = stringResource(Res.string.send_email_button),
-            onClick = { onPasswordResetComplete(email) },
+            onClick = {
+                viewModel.sendPasswordResetEmail(email)
+            },
             enabled = email.isNotBlank(),
             modifier = Modifier
                 .align(Alignment.BottomCenter)
                 .padding(horizontal = 16.dp)
                 .padding(bottom = 52.dp)
         )
+
+        // 토스트 메시지 (Snackbar)
+        if (showSuccessToast) {
+            Snackbar(
+                modifier = Modifier
+                    .align(Alignment.BottomCenter)
+                    .padding(bottom = 120.dp)
+                    .padding(horizontal = 16.dp),
+                containerColor = Color(0xFF4CAF50),
+                contentColor = Color.White
+            ) {
+                Text(
+                    text = "이메일로 임시 비밀번호가 전송되었습니다.",
+                    fontSize = 14.sp,
+                    fontWeight = FontWeight.W500
+                )
+            }
+        }
     }
 }
 
@@ -97,8 +138,6 @@ fun PasswordResetScreenPreview() {
     FindPasswordScreen(
         modifier = Modifier,
         onNavigateBack = {},
-        onPasswordResetComplete = { email ->
-            // 이메일 처리 로직
-        }
+        onPasswordResetComplete = {}
     )
 }
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/LoginScreen.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/LoginScreen.kt
index 871d8ed..9c2b6fe 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/LoginScreen.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/LoginScreen.kt
@@ -11,9 +11,12 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.material3.ButtonDefaults
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -27,8 +30,11 @@ import androidx.compose.ui.unit.sp
 import org.jetbrains.compose.resources.painterResource
 import org.jetbrains.compose.resources.stringResource
 import org.jetbrains.compose.ui.tooling.preview.Preview
+import org.koin.compose.viewmodel.koinViewModel
 import org.whosin.client.presentation.auth.login.component.CommonLoginButton
 import org.whosin.client.presentation.auth.login.component.CommonLoginInputField
+import org.whosin.client.presentation.auth.login.viewmodel.LoginUiState
+import org.whosin.client.presentation.auth.login.viewmodel.LoginViewModel
 import whosinclient.composeapp.generated.resources.Res
 import whosinclient.composeapp.generated.resources.email_label
 import whosinclient.composeapp.generated.resources.email_placeholder
@@ -45,10 +51,18 @@ fun LoginScreen(
     modifier: Modifier = Modifier,
     onNavigateToHome: () -> Unit,
     onNavigateToFindPassword: () -> Unit = {},
-    onNavigateToSignup: () -> Unit = {}
+    onNavigateToSignup: () -> Unit = {},
+    viewModel: LoginViewModel = koinViewModel()
 ) {
     var email by remember { mutableStateOf("") }
     var password by remember { mutableStateOf("") }
+    val uiState by viewModel.uiState.collectAsState()
+
+    LaunchedEffect(uiState.isSuccess) {
+        if (uiState.isSuccess) {
+            onNavigateToHome()
+        }
+    }
 
     Box(
         modifier = modifier
@@ -106,9 +120,22 @@ fun LoginScreen(
                     modifier = Modifier.padding(bottom = 16.dp)
                 )
 
+                uiState.errorMessage?.let { errorMsg ->
+                    Text(
+                        text = errorMsg,
+                        color = Color.Red,
+                        fontSize = 14.sp,
+                        fontWeight = FontWeight.W400,
+                        modifier = Modifier.padding(bottom = 16.dp)
+                    )
+                }
+
                 CommonLoginButton(
                     text = stringResource(Res.string.login_button),
-                    onClick = onNavigateToHome,
+                    onClick = {
+                        viewModel.login(email, password)
+                    },
+                    enabled = email.isNotBlank() && password.isNotBlank() && !uiState.isLoading,
                     modifier = Modifier.padding(bottom = 12.dp)
                 )
             }
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/NicknameInputScreen.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/NicknameInputScreen.kt
index 17b11d6..4e0530f 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/NicknameInputScreen.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/NicknameInputScreen.kt
@@ -3,13 +3,18 @@ package org.whosin.client.presentation.auth.login
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -23,8 +28,11 @@ import androidx.compose.ui.unit.sp
 import coil3.compose.AsyncImage
 import org.jetbrains.compose.resources.stringResource
 import org.jetbrains.compose.ui.tooling.preview.Preview
+import org.koin.compose.viewmodel.koinViewModel
 import org.whosin.client.presentation.auth.login.component.CommonLoginButton
 import org.whosin.client.presentation.auth.login.component.CommonLoginInputField
+import org.whosin.client.presentation.auth.login.viewmodel.SignupUiState
+import org.whosin.client.presentation.auth.login.viewmodel.SignupViewModel
 import whosinclient.composeapp.generated.resources.Res
 import whosinclient.composeapp.generated.resources.back_button
 import whosinclient.composeapp.generated.resources.next_button
@@ -35,10 +43,29 @@ import whosinclient.composeapp.generated.resources.nickname_welcome_title
 @Composable
 fun NicknameInputScreen(
     modifier: Modifier = Modifier,
+    email: String,
+    password: String,
     onNavigateBack: () -> Unit = {},
-    onNavigateToClubCode: (String) -> Unit = {}
+    onNavigateToClubCode: () -> Unit = {},
+    viewModel: SignupViewModel = koinViewModel()
 ) {
     var nickname by remember { mutableStateOf("") }
+    var errorMessage by remember { mutableStateOf<String?>(null) }
+    val uiState by viewModel.uiState.collectAsState()
+
+    LaunchedEffect(uiState) {
+        when (uiState) {
+            is SignupUiState.Success -> {
+                onNavigateToClubCode()
+            }
+
+            is SignupUiState.Error -> {
+                errorMessage = (uiState as SignupUiState.Error).message
+            }
+
+            else -> {}
+        }
+    }
 
     Box(
         modifier = modifier
@@ -85,17 +112,38 @@ fun NicknameInputScreen(
                 value = nickname,
                 onValueChange = { newValue ->
                     nickname = newValue
+                    errorMessage = null
                 },
                 placeholder = stringResource(Res.string.nickname_input_placeholder),
                 maxLength = 8
             )
+
+            if (errorMessage != null) {
+                Spacer(modifier = Modifier.height(8.dp))
+                Text(
+                    text = errorMessage ?: "",
+                    color = Color.Red,
+                    fontSize = 14.sp,
+                    fontWeight = FontWeight.W400
+                )
+            }
+
+            if (uiState is SignupUiState.Loading) {
+                Spacer(modifier = Modifier.height(16.dp))
+                CircularProgressIndicator(
+                    modifier = Modifier.size(24.dp),
+                    color = Color(0xFFFF7A00)
+                )
+            }
         }
 
         // 하단 다음 버튼
         CommonLoginButton(
             text = stringResource(Res.string.next_button),
-            onClick = { onNavigateToClubCode(nickname) },
-            enabled = nickname.isNotBlank(),
+            onClick = {
+                viewModel.signup(email, password, nickname)
+            },
+            enabled = nickname.isNotBlank() && uiState !is SignupUiState.Loading,
             modifier = Modifier
                 .align(Alignment.BottomCenter)
                 .padding(horizontal = 16.dp)
@@ -109,9 +157,9 @@ fun NicknameInputScreen(
 fun NicknameInputScreenPreview() {
     NicknameInputScreen(
         modifier = Modifier,
+        email = "test@example.com",
+        password = "password123",
         onNavigateBack = {},
-        onNavigateToClubCode = { nickname ->
-            // 닉네임 처리 로직
-        }
+        onNavigateToClubCode = {}
     )
 }
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/PasswordInputScreen.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/PasswordInputScreen.kt
index 821483b..dde7687 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/PasswordInputScreen.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/PasswordInputScreen.kt
@@ -43,7 +43,9 @@ fun PasswordInputScreen(
     var password by remember { mutableStateOf("") }
     var confirmPassword by remember { mutableStateOf("") }
 
-    val isComplete = password.isNotBlank() && confirmPassword.isNotBlank()
+    val isComplete = password.length >= 8 &&
+            confirmPassword.length >= 8 &&
+            password == confirmPassword
 
     Box(
         modifier = modifier
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/SignupEmailInputScreen.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/SignupEmailInputScreen.kt
index 5d988a4..cda015f 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/SignupEmailInputScreen.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/SignupEmailInputScreen.kt
@@ -9,6 +9,7 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.Text
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -25,6 +26,11 @@ import org.jetbrains.compose.resources.stringResource
 import org.jetbrains.compose.ui.tooling.preview.Preview
 import org.whosin.client.presentation.auth.login.component.CommonLoginButton
 import org.whosin.client.presentation.auth.login.component.CommonLoginInputField
+import org.whosin.client.data.repository.AuthRepository
+import org.whosin.client.core.network.ApiResult
+import androidx.compose.runtime.rememberCoroutineScope
+import kotlinx.coroutines.launch
+import org.koin.compose.koinInject
 import whosinclient.composeapp.generated.resources.Res
 import whosinclient.composeapp.generated.resources.back_button
 import whosinclient.composeapp.generated.resources.email_placeholder
@@ -38,6 +44,10 @@ fun SignupScreen(
     onNavigateToEmailVerification: (String) -> Unit = {}
 ) {
     var email by remember { mutableStateOf("") }
+    var isLoading by remember { mutableStateOf(false) }
+
+    val authRepository: AuthRepository = koinInject()
+    val coroutineScope = rememberCoroutineScope()
 
     Box(
         modifier = modifier
@@ -81,13 +91,40 @@ fun SignupScreen(
 
         CommonLoginButton(
             text = stringResource(Res.string.next_button),
-            onClick = { onNavigateToEmailVerification(email) },
-            enabled = email.isNotBlank(),
+            onClick = {
+                if (email.isNotBlank() && !isLoading) {
+                    isLoading = true
+
+                    coroutineScope.launch {
+                        when (authRepository.sendEmailVerification(email)) {
+                            is ApiResult.Success<*> -> {
+                                isLoading = false
+                                onNavigateToEmailVerification(email)
+                            }
+
+                            is ApiResult.Error -> {
+                                isLoading = false
+                            }
+                        }
+                    }
+                }
+            },
+            enabled = email.isNotBlank() && !isLoading,
             modifier = Modifier
                 .align(Alignment.BottomCenter)
                 .padding(horizontal = 16.dp)
                 .padding(bottom = 52.dp)
         )
+
+        // 로딩 인디케이터
+        if (isLoading) {
+            CircularProgressIndicator(
+                color = Color(0xFFF89531),
+                modifier = Modifier
+                    .align(Alignment.Center)
+                    .size(48.dp)
+            )
+        }
     }
 }
 
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/SplashScreen.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/SplashScreen.kt
index 616f400..0c6db38 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/SplashScreen.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/SplashScreen.kt
@@ -7,6 +7,8 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.size
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
@@ -14,18 +16,33 @@ import androidx.compose.ui.unit.dp
 import kotlinx.coroutines.delay
 import org.jetbrains.compose.resources.painterResource
 import org.jetbrains.compose.ui.tooling.preview.Preview
+import org.koin.compose.viewmodel.koinViewModel
+import org.whosin.client.presentation.auth.login.viewmodel.SplashViewModel
 import whosinclient.composeapp.generated.resources.Res
 import whosinclient.composeapp.generated.resources.img_logo_white
 
 @Composable
 fun SplashScreen(
     modifier: Modifier = Modifier,
-    onNavigateToLogin: () -> Unit = {}
+    onNavigateToLogin: () -> Unit = {},
+    onNavigateToHome: () -> Unit = {},
+    viewModel: SplashViewModel = koinViewModel()
 ) {
+    val uiState by viewModel.uiState.collectAsState()
 
     LaunchedEffect(Unit) {
-        delay(2000)
-        onNavigateToLogin()
+        delay(1500) // 스플래시 화면 표시 시간
+        viewModel.checkToken()
+    }
+
+    LaunchedEffect(uiState.isLoading) {
+        if (!uiState.isLoading) {
+            if (uiState.hasToken) {
+                onNavigateToHome()
+            } else {
+                onNavigateToLogin()
+            }
+        }
     }
 
     Box(
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/component/NumberInputBox.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/component/NumberInputBox.kt
index 76a8b36..33931ff 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/component/NumberInputBox.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/component/NumberInputBox.kt
@@ -2,6 +2,7 @@ package org.whosin.client.presentation.auth.login.component
 
 import androidx.compose.foundation.background
 import androidx.compose.foundation.border
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.size
@@ -35,6 +36,7 @@ fun NumberInputBox(
     onValueChange: (String) -> Unit,
     onBackspace: (() -> Unit)? = null,
     onFocusChanged: ((Boolean) -> Unit)? = null,
+    onClick: (() -> Unit)? = null,
     containerColor: Color = Color.White,
     borderColor: Color = Color(0xFFE5E5E5),
     focusedBorderColor: Color = Color(0xFFF89531),
@@ -63,7 +65,8 @@ fun NumberInputBox(
         modifier = modifier
             .size(width = 50.dp, height = 54.dp)
             .background(containerColor, RoundedCornerShape(8.dp))
-            .border(1.dp, currentBorderColor, RoundedCornerShape(8.dp)),
+            .border(1.dp, currentBorderColor, RoundedCornerShape(8.dp))
+            .clickable { onClick?.invoke() },
         contentAlignment = Alignment.Center
     ) {
         BasicTextField(
@@ -87,13 +90,17 @@ fun NumberInputBox(
             ),
             singleLine = true,
             keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number),
-            cursorBrush = SolidColor(Color(0xFFB2B2B2)),
-            modifier = Modifier.onFocusChanged { focusState ->
-                onFocusChanged?.invoke(focusState.isFocused)
-            },
+            cursorBrush = SolidColor(Color.Transparent),
+            modifier = Modifier
+                .fillMaxSize()
+                .onFocusChanged { focusState ->
+                    onFocusChanged?.invoke(focusState.isFocused)
+                },
             decorationBox = { innerTextField ->
                 Box(
-                    Modifier.fillMaxSize(),
+                    Modifier
+                        .fillMaxSize()
+                        .clickable { onClick?.invoke() },
                     contentAlignment = Alignment.Center
                 ) {
                     innerTextField()
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/FindPasswordViewModel.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/FindPasswordViewModel.kt
new file mode 100644
index 0000000..32a4a46
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/FindPasswordViewModel.kt
@@ -0,0 +1,38 @@
+package org.whosin.client.presentation.auth.login.viewmodel
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.launch
+import org.whosin.client.core.network.ApiResult
+import org.whosin.client.data.repository.AuthRepository
+
+sealed interface FindPasswordUiState {
+    data object Idle: FindPasswordUiState
+    data object Loading: FindPasswordUiState
+    data object Success: FindPasswordUiState
+    data class Error(val message: String?): FindPasswordUiState
+}
+
+class FindPasswordViewModel(
+    private val repository: AuthRepository
+): ViewModel() {
+    private val _uiState: MutableStateFlow<FindPasswordUiState> = MutableStateFlow(FindPasswordUiState.Idle)
+    val uiState: StateFlow<FindPasswordUiState> = _uiState
+
+    fun sendPasswordResetEmail(email: String) {
+        _uiState.value = FindPasswordUiState.Loading
+        viewModelScope.launch {
+            when (val result = repository.sendPasswordResetEmail(email)) {
+                is ApiResult.Success -> {
+                    _uiState.value = FindPasswordUiState.Success
+                }
+                is ApiResult.Error -> {
+                    val message = result.message ?: result.cause?.message
+                    _uiState.value = FindPasswordUiState.Error(message)
+                }
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/LoginViewModel.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/LoginViewModel.kt
index 7517f45..8f54d20 100644
--- a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/LoginViewModel.kt
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/LoginViewModel.kt
@@ -5,32 +5,52 @@ import androidx.lifecycle.viewModelScope
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.launch
+import org.whosin.client.core.datastore.TokenManager
 import org.whosin.client.core.network.ApiResult
-import org.whosin.client.data.repository.MemberRepository
-import org.whosin.client.data.dto.response.TokenDto
+import org.whosin.client.data.repository.AuthRepository
 
-sealed interface LoginUiState {
-    data object Loading: LoginUiState
-    data class Success(val token: TokenDto): LoginUiState
-    data class Error(val message: String?): LoginUiState
-}
+data class LoginUiState(
+    val isLoading: Boolean = false,
+    val isSuccess: Boolean = false,
+    val errorMessage: String? = null
+)
 
 class LoginViewModel(
-    private val repository: MemberRepository
+    private val repository: AuthRepository,
+    private val tokenManager: TokenManager
 ): ViewModel() {
-    private val _uiState: MutableStateFlow<LoginUiState?> = MutableStateFlow(null)
-    val uiState: StateFlow<LoginUiState?> = _uiState
+    private val _uiState = MutableStateFlow(LoginUiState())
+    val uiState: StateFlow<LoginUiState> = _uiState
 
     fun login(email: String, password: String) {
-        _uiState.value = LoginUiState.Loading
         viewModelScope.launch {
+            _uiState.value = _uiState.value.copy(isLoading = true, errorMessage = null)
+
             when (val result = repository.login(email, password)) {
                 is ApiResult.Success -> {
-                    _uiState.value = LoginUiState.Success(result.data.data)
+                    val tokenData = result.data.data
+                    if (tokenData != null) {
+                        tokenManager.saveTokens(
+                            accessToken = tokenData.accessToken,
+                            refreshToken = tokenData.refreshToken
+                        )
+                        _uiState.value = _uiState.value.copy(
+                            isLoading = false,
+                            isSuccess = true,
+                            errorMessage = null
+                        )
+                    } else {
+                        _uiState.value = _uiState.value.copy(
+                            isLoading = false,
+                            errorMessage = "토큰 데이터를 받지 못했습니다."
+                        )
+                    }
                 }
                 is ApiResult.Error -> {
-                    val message = result.message ?: result.cause?.message
-                    _uiState.value = LoginUiState.Error(message)
+                    _uiState.value = _uiState.value.copy(
+                        isLoading = false,
+                        errorMessage = result.message ?: "로그인에 실패했습니다."
+                    )
                 }
             }
         }
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/SignupViewModel.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/SignupViewModel.kt
new file mode 100644
index 0000000..5cffbbb
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/SignupViewModel.kt
@@ -0,0 +1,58 @@
+package org.whosin.client.presentation.auth.login.viewmodel
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.launch
+import org.whosin.client.core.datastore.TokenManager
+import org.whosin.client.core.network.ApiResult
+import org.whosin.client.data.repository.AuthRepository
+
+sealed interface SignupUiState {
+    data object Idle: SignupUiState
+    data object Loading: SignupUiState
+    data object Success: SignupUiState
+    data class Error(val message: String?): SignupUiState
+}
+
+class SignupViewModel(
+    private val repository: AuthRepository,
+    private val tokenManager: TokenManager
+): ViewModel() {
+    private val _uiState: MutableStateFlow<SignupUiState> = MutableStateFlow(SignupUiState.Idle)
+    val uiState: StateFlow<SignupUiState> = _uiState
+
+    fun signup(email: String, password: String, nickName: String) {
+        _uiState.value = SignupUiState.Loading
+        viewModelScope.launch {
+            when (val signupResult = repository.signup(email, password, nickName)) {
+                is ApiResult.Success -> {
+                    // 회원가입 성공 시 자동 로그인
+                    when (val loginResult = repository.login(email, password)) {
+                        is ApiResult.Success -> {
+                            val tokenData = loginResult.data.data
+                            if (tokenData != null) {
+                                tokenManager.saveTokens(
+                                    accessToken = tokenData.accessToken,
+                                    refreshToken = tokenData.refreshToken
+                                )
+                                _uiState.value = SignupUiState.Success
+                            } else {
+                                _uiState.value = SignupUiState.Error("로그인 후 토큰 데이터를 받지 못했습니다.")
+                            }
+                        }
+                        is ApiResult.Error -> {
+                            val message = loginResult.message ?: loginResult.cause?.message
+                            _uiState.value = SignupUiState.Error(message)
+                        }
+                    }
+                }
+                is ApiResult.Error -> {
+                    val message = signupResult.message ?: signupResult.cause?.message
+                    _uiState.value = SignupUiState.Error(message)
+                }
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/SplashViewModel.kt b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/SplashViewModel.kt
new file mode 100644
index 0000000..fe4c8f3
--- /dev/null
+++ b/composeApp/src/commonMain/kotlin/org/whosin/client/presentation/auth/login/viewmodel/SplashViewModel.kt
@@ -0,0 +1,32 @@
+package org.whosin.client.presentation.auth.login.viewmodel
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.launch
+import org.whosin.client.core.datastore.TokenManager
+
+data class SplashUiState(
+    val isLoading: Boolean = true,
+    val hasToken: Boolean = false
+)
+
+class SplashViewModel(
+    private val tokenManager: TokenManager
+) : ViewModel() {
+    private val _uiState = MutableStateFlow(SplashUiState())
+    val uiState: StateFlow<SplashUiState> = _uiState
+
+    fun checkToken() {
+        viewModelScope.launch {
+            val accessToken = tokenManager.getAccessToken()
+            val hasValidToken = !accessToken.isNullOrEmpty()
+
+            _uiState.value = _uiState.value.copy(
+                isLoading = false,
+                hasToken = hasValidToken
+            )
+        }
+    }
+}