diff --git a/internal/curlwrapper.hpp b/internal/curlwrapper.hpp
index 4e0e40a..7a400c3 100644
--- a/internal/curlwrapper.hpp
+++ b/internal/curlwrapper.hpp
@@ -7,70 +7,78 @@
 #ifndef CURLWRAPPER_HPP
 #define CURLWRAPPER_HPP
 
+#include <memory>
 #include <string>
 #include <curl/curl.h>
 
-static size_t WriteCallback(void* contents, size_t size, size_t nmemb, std::string* userp) {
-    userp->append((char*)contents, size * nmemb);
-    return size * nmemb;
-}
+using FilePtr = std::unique_ptr<FILE, decltype(&fclose)>;
+using CurlPtr = std::unique_ptr<CURL, decltype(&curl_easy_cleanup)>;
+using CurlSlist = std::unique_ptr<curl_slist, decltype(&curl_slist_free_all)>;
 
-static size_t WriteFileCallback(void* ptr, size_t size, size_t nmemb, FILE* stream) {
-    return fwrite(ptr, size, nmemb, stream);
+static FilePtr openFile(const char *path, const char *mode) {
+    return FilePtr{fopen(path, mode), &fclose};
 }
 
-static std::string strToString(__jule_Str str) {
-    std::string result = "";
-    for (__jule_U8& c : str) {
-        result += c;
-    }
-    return result;
+static CurlPtr initCurl() {
+    return CurlPtr{curl_easy_init(), &curl_easy_cleanup};
 }
 
-static struct curl_slist* sliceToSlist(const __jule_Slice<__jule_Str> headersSlice) {
+static struct curl_slist* sliceToSlist(const __jule_Slice<__jule_Str> &headersSlice) {
     struct curl_slist* headers = NULL;
     const int headersLen = headersSlice.len();
     for (size_t i = 0; i < headersLen; i += 2) {
         if (i + 1 < headersLen) {
-            std::string header = strToString(headersSlice[i]) + ": " + strToString(headersSlice[i + 1]);
+            const std::string header{headersSlice[i] + ": " + headersSlice[i + 1]};
+            // header.c_str() is cloned, so you don't have to worry about the lifetime here.
             headers = curl_slist_append(headers, header.c_str());
         }
     }
     return headers;
 }
 
+static CurlSlist initHeadersList(const __jule_Slice<__jule_Str> &headers) {
+    return CurlSlist{sliceToSlist(headers), &curl_slist_free_all};
+}
+
+static size_t WriteCallback(void* contents, size_t size, size_t nmemb, std::string* userp) {
+    userp->append((char*)contents, size * nmemb);
+    return size * nmemb;
+}
+
+static size_t WriteFileCallback(void* ptr, size_t size, size_t nmemb, FILE* stream) {
+    return fwrite(ptr, size, nmemb, stream);
+}
+
 struct Response {
     __jule_Str body;
     __jule_Int status;
 };
 
-static Response request(const char *url, const __jule_Slice<__jule_Str> headers, const __jule_Int method) {
-    CURL* curl;
+static Response request(const char *url, const __jule_Slice<__jule_Str> &headers, const __jule_Int method) {
     CURLcode res;
     std::string readBuffer;
 
     Response response;
-    struct curl_slist* headersList = sliceToSlist(headers);
+    CurlSlist headersList = initHeadersList(headers);
 
-    curl = curl_easy_init();
+    CurlPtr curl = initCurl();
     if (!curl) {
         response.status = 418;
         return response;
     }
 
-    curl_easy_setopt(curl, CURLOPT_URL, url);
-    curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headersList);
+    curl_easy_setopt(curl.get(), CURLOPT_URL, url);
+    curl_easy_setopt(curl.get(), CURLOPT_HTTPHEADER, headersList.get());
 
     if (method == 0) { // GET
-        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);
-        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &readBuffer);
+        curl_easy_setopt(curl.get(), CURLOPT_WRITEFUNCTION, WriteCallback);
+        curl_easy_setopt(curl.get(), CURLOPT_WRITEDATA, &readBuffer);
     } else if (method == 1) { // HEAD
-        curl_easy_setopt(curl, CURLOPT_NOBODY, 1L);
+        curl_easy_setopt(curl.get(), CURLOPT_NOBODY, 1L);
     }
 
-    res = curl_easy_perform(curl);
-    curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &response.status);
-    curl_easy_cleanup(curl);
+    res = curl_easy_perform(curl.get());
+    curl_easy_getinfo(curl.get(), CURLINFO_RESPONSE_CODE, &response.status);
 
     if (method == 0) { // GET
         response.body = readBuffer;
@@ -79,40 +87,38 @@ static Response request(const char *url, const __jule_Slice<__jule_Str> headers,
     return response;
 }
 
-static Response post(const char *url, const char *data, const __jule_Slice<__jule_Str> headers, const __jule_Int method) {
-    CURL* curl;
+static Response post(const char *url, const char *data, const __jule_Slice<__jule_Str> &headers, const __jule_Int method) {
     CURLcode res;
     std::string readBuffer;
 
     Response response;
-    struct curl_slist* headersList = sliceToSlist(headers);
+    CurlSlist headersList = initHeadersList(headers);
 
-    curl = curl_easy_init();
+    CurlPtr curl = initCurl();
     if (!curl) {
         response.status = 418;
         return response;
     }
 
-    curl_easy_setopt(curl, CURLOPT_URL, url);
-    curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headersList);
+    curl_easy_setopt(curl.get(), CURLOPT_URL, url);
+    curl_easy_setopt(curl.get(), CURLOPT_HTTPHEADER, headersList.get());
 
     if (method == 0) { // POST
-        curl_easy_setopt(curl, CURLOPT_POST, 1L);
+        curl_easy_setopt(curl.get(), CURLOPT_POST, 1L);
     } else if (method == 1) { // PUT
-        curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "PUT");
+        curl_easy_setopt(curl.get(), CURLOPT_CUSTOMREQUEST, "PUT");
     } else if (method == 2) { // DELETE
-        curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "DELETE");
+        curl_easy_setopt(curl.get(), CURLOPT_CUSTOMREQUEST, "DELETE");
     }
 
     if (data) {
-        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, data);
+        curl_easy_setopt(curl.get(), CURLOPT_POSTFIELDS, data);
     }
-    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);
-    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &readBuffer);
+    curl_easy_setopt(curl.get(), CURLOPT_WRITEFUNCTION, WriteCallback);
+    curl_easy_setopt(curl.get(), CURLOPT_WRITEDATA, &readBuffer);
 
-    res = curl_easy_perform(curl);
-    curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &response.status);
-    curl_easy_cleanup(curl);
+    res = curl_easy_perform(curl.get());
+    curl_easy_getinfo(curl.get(), CURLINFO_RESPONSE_CODE, &response.status);
 
     response.body = readBuffer;
 
@@ -120,29 +126,26 @@ static Response post(const char *url, const char *data, const __jule_Slice<__jul
 }
 
 static bool download(__jule_Str url, __jule_Str filename) {
-    CURL* curl = curl_easy_init();
+    CurlPtr curl = initCurl();
     if (!curl) {
         return false;
     }
 
-    FILE* file = fopen(strToString(filename).c_str(), "wb");
+    FilePtr file{openFile(filename, "wb")};
     if (!file) {
         return false;
     }
 
-    curl_easy_setopt(curl, CURLOPT_URL, strToString(url).c_str());
-    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteFileCallback);
-    curl_easy_setopt(curl, CURLOPT_WRITEDATA, file);
+    // curl_easy_setopt is a macro, so implicit conversion don't happen.
+    curl_easy_setopt(curl.get(), CURLOPT_URL, (const char*)url);
+    curl_easy_setopt(curl.get(), CURLOPT_WRITEFUNCTION, WriteFileCallback);
+    curl_easy_setopt(curl.get(), CURLOPT_WRITEDATA, file.get());
 
-    curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
+    curl_easy_setopt(curl.get(), CURLOPT_FOLLOWLOCATION, 1L);
 
-    curl_easy_perform(curl);
-
-    fclose(file);
-    curl_easy_cleanup(curl);
+    curl_easy_perform(curl.get());
 
     return true;
 }
 
 #endif // CURLWRAPPER_HPP
-