diff --git a/packages/celest_auth/CHANGELOG.md b/packages/celest_auth/CHANGELOG.md
index 82866d4c..eef20f21 100644
--- a/packages/celest_auth/CHANGELOG.md
+++ b/packages/celest_auth/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.3.0-dev.2
+
+- Clear browser cookies on `signOut`
+
 ## 0.3.0-dev.1
 
 - Initial version.
diff --git a/packages/celest_auth/lib/src/auth.dart b/packages/celest_auth/lib/src/auth.dart
index 98c0b7b2..c44127fe 100644
--- a/packages/celest_auth/lib/src/auth.dart
+++ b/packages/celest_auth/lib/src/auth.dart
@@ -20,5 +20,5 @@ abstract interface class Auth {
   Stream<AuthState> get authStateChanges;
 
   /// Signs out the current user, if any.
-  void signOut();
+  Future<void> signOut();
 }
diff --git a/packages/celest_auth/lib/src/auth_impl.dart b/packages/celest_auth/lib/src/auth_impl.dart
index 6e6aa108..eb0cb8db 100644
--- a/packages/celest_auth/lib/src/auth_impl.dart
+++ b/packages/celest_auth/lib/src/auth_impl.dart
@@ -82,10 +82,14 @@ final class AuthImpl implements Auth {
   }
 
   @override
-  void signOut() {
+  Future<void> signOut() async {
     localStorage.delete('userId');
     secureStorage.delete('cork');
-    _authStateController.add(const Unauthenticated());
+    try {
+      await protocol.signOut();
+    } finally {
+      _authStateController.add(const Unauthenticated());
+    }
   }
 
   final CelestBase celest;
diff --git a/packages/celest_auth/pubspec.yaml b/packages/celest_auth/pubspec.yaml
index dbe7ea85..dbb2918f 100644
--- a/packages/celest_auth/pubspec.yaml
+++ b/packages/celest_auth/pubspec.yaml
@@ -1,6 +1,6 @@
 name: celest_auth
 description: The Auth runtime and client library for Celest, the Flutter cloud platform.
-version: 0.3.0-dev.1
+version: 0.3.0-dev.2
 homepage: https://celest.dev
 repository: https://github.com/celest-dev/celest/tree/main/packages/celest_auth
 
@@ -12,7 +12,7 @@ dependencies:
   built_collection: ^5.1.1
   built_value: ^8.9.1
   cedar: ^0.1.0
-  celest_core: ^0.3.0-dev.1
+  celest_core: ^0.3.0-dev.2
   chunked_stream: ^1.4.2
   corks_cedar: ^0.1.0
   ffi: ^2.1.2
diff --git a/packages/celest_core/CHANGELOG.md b/packages/celest_core/CHANGELOG.md
index e4d89a51..0dde39b5 100644
--- a/packages/celest_core/CHANGELOG.md
+++ b/packages/celest_core/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.3.0-dev.2
+
+- Add `signOut` method to `AuthProtocol` for clearing browser cookies
+
 ## 0.3.0-dev.1
 
 - Adds `SecureStorage` interface for storage of sensitive data in the platform keychain
diff --git a/packages/celest_core/lib/src/auth/auth_client.dart b/packages/celest_core/lib/src/auth/auth_client.dart
index a18d9d3b..a6599d30 100644
--- a/packages/celest_core/lib/src/auth/auth_client.dart
+++ b/packages/celest_core/lib/src/auth/auth_client.dart
@@ -16,6 +16,11 @@ final class AuthClient with BaseProtocol implements AuthProtocol {
     return User.fromJson(response);
   }
 
+  @override
+  Future<void> signOut() async {
+    await postJson('/_auth/sign-out', {});
+  }
+
   @override
   late final EmailClient email = EmailClient(celest);
 }
diff --git a/packages/celest_core/lib/src/auth/auth_protocol.dart b/packages/celest_core/lib/src/auth/auth_protocol.dart
index 3a7712c6..d5bbec0a 100644
--- a/packages/celest_core/lib/src/auth/auth_protocol.dart
+++ b/packages/celest_core/lib/src/auth/auth_protocol.dart
@@ -5,6 +5,7 @@ abstract interface class AuthProtocol {
   EmailProtocol get email;
 
   Future<User> userInfo();
+  Future<void> signOut();
 }
 
 abstract interface class EmailProtocol {
diff --git a/packages/celest_core/pubspec.yaml b/packages/celest_core/pubspec.yaml
index 88c0916f..b35d4c3c 100644
--- a/packages/celest_core/pubspec.yaml
+++ b/packages/celest_core/pubspec.yaml
@@ -1,6 +1,6 @@
 name: celest_core
 description: Celest types and utilities shared between the client and the cloud.
-version: 0.3.0-dev.1
+version: 0.3.0-dev.2
 homepage: https://celest.dev
 repository: https://github.com/celest-dev/celest/tree/main/packages/celest_core