diff --git a/src/auth/auth.cpp b/src/auth/auth.cpp
index 1dda20e..3911486 100644
--- a/src/auth/auth.cpp
+++ b/src/auth/auth.cpp
@@ -24,7 +24,7 @@ void auth(const httplib::Request& request, httplib::Response& response) {
 
     if (userid == "") {response.set_content("{\"status\":\"403\"}", "application/json");return;}
 
-    auto token = jwt::create()
+    std::string token = jwt::create()
         .set_type("JWT")
         .set_issuer("auth0")
         .set_payload_claim("userId", jwt::claim(userid))
diff --git a/src/auth/verify_auth.cpp b/src/auth/verify_auth.cpp
index bb35510..1dc9d8d 100644
--- a/src/auth/verify_auth.cpp
+++ b/src/auth/verify_auth.cpp
@@ -4,10 +4,10 @@
 bool verify_auth(const std::string token) {
     try {
         // parse token
-        const auto decoded = jwt::decode(token);
+        const jwt::decoded_jwt<jwt::traits::kazuho_picojson> decoded = jwt::decode(token);
 
         // validate token
-        const auto verifier = jwt::verify()
+        const jwt::verifier<jwt::default_clock, jwt::traits::kazuho_picojson> verifier = jwt::verify()
                                 .allow_algorithm(jwt::algorithm::hs256{JWT_SECRET_KEY})
                                 .with_issuer("auth0");
 
diff --git a/src/users/add_user.cpp b/src/users/add_user.cpp
index 3566e9c..0cb3b62 100644
--- a/src/users/add_user.cpp
+++ b/src/users/add_user.cpp
@@ -22,7 +22,7 @@ void add_user(const httplib::Request& request, httplib::Response& response) {
     if (json_body["username"] == nullptr) {response.set_content("{\"required\":\"[token,username,password]\",\"optional\":\"[group,is_superuser]\"}", "application/json");return;}
     if (json_body["password"] == nullptr) {response.set_content("{\"required\":\"[token,username,password]\",\"optional\":\"[group,is_superuser]\"}", "application/json");return;}
 
-    auto decoded_token = jwt::decode(json_body["token"]);
+    jwt::decoded_jwt<jwt::traits::kazuho_picojson> decoded_token = jwt::decode(json_body["token"]);
     std::string userid = "";
     for (auto& e : decoded_token.get_payload_json()) {
         if (e.first == "userId") {
@@ -37,7 +37,7 @@ void add_user(const httplib::Request& request, httplib::Response& response) {
     usersfile.close();
 
     nlohmann::json response_user_data = nullptr;
-    for (auto& user : all_users) {
+    for (nlohmann::json& user : all_users) {
         if (user["id"] == userid) {
             response_user_data = user;
         }
@@ -48,7 +48,7 @@ void add_user(const httplib::Request& request, httplib::Response& response) {
     const std::string username = json_body["username"];
     const std::string password = json_body["password"];
 
-    for (auto& user : all_users) {
+    for (nlohmann::json user : all_users) {
         if ((user["username"] == username)) {
             response.set_content("{\"status\":\"user already exists\"}", "application/json");return;
         }
diff --git a/src/users/change_password.cpp b/src/users/change_password.cpp
index 82af660..0732ea1 100644
--- a/src/users/change_password.cpp
+++ b/src/users/change_password.cpp
@@ -24,7 +24,7 @@ void change_password(const httplib::Request& request, httplib::Response& respons
 
     if (json_body["userid"] == nullptr) {old_password = json_body["old_password"];}
 
-    auto decoded_token = jwt::decode(json_body["token"]);
+    jwt::decoded_jwt<jwt::traits::kazuho_picojson> decoded_token = jwt::decode(json_body["token"]);
     std::string userid = "";
     for (auto& e : decoded_token.get_payload_json()) {
         if (e.first == "userId") {
@@ -42,7 +42,7 @@ void change_password(const httplib::Request& request, httplib::Response& respons
     if (json_body["userid"] != nullptr) {
         changepassuserid = json_body["userid"];
         nlohmann::json response_user_data = nullptr;
-        for (auto& user : all_users) {
+        for (nlohmann::json& user : all_users) {
             if (user["id"] == userid) {
                 response_user_data = user;
             }
diff --git a/src/users/delete_user.cpp b/src/users/delete_user.cpp
index 83ff2d3..bb62514 100644
--- a/src/users/delete_user.cpp
+++ b/src/users/delete_user.cpp
@@ -8,7 +8,7 @@ void delete_user(const httplib::Request& request, httplib::Response& response) {
     if (json_body["token"] == nullptr) {response.set_content("{\"required\":\"[token] or if you superuser [token,userid]\"}", "application/json");return;}
     if (!verify_auth(json_body["token"])) {response.set_content("{\"status\":\"403\"}", "application/json");return;}
 
-    auto decoded_token = jwt::decode(json_body["token"]);
+    jwt::decoded_jwt<jwt::traits::kazuho_picojson> decoded_token = jwt::decode(json_body["token"]);
     std::string userid = "";
     for (auto& e : decoded_token.get_payload_json()) {
         if (e.first == "userId") {
@@ -26,7 +26,7 @@ void delete_user(const httplib::Request& request, httplib::Response& response) {
     if (json_body["userid"] != nullptr) {
         deluserid = json_body["userid"];
         nlohmann::json response_user_data = nullptr;
-        for (auto& user : all_users) {
+        for (nlohmann::json& user : all_users) {
             if (user["id"] == userid) {
                 response_user_data = user;
             }
diff --git a/src/users/get_all_users.cpp b/src/users/get_all_users.cpp
index cbf4391..e9f462c 100644
--- a/src/users/get_all_users.cpp
+++ b/src/users/get_all_users.cpp
@@ -7,7 +7,7 @@ void get_all_users(const httplib::Request& request, httplib::Response& response)
 
     if (json_body["token"] == nullptr) {response.set_content("{\"required\":\"[token]\"}", "application/json");return;}
     if (!verify_auth(json_body["token"])) {response.set_content("{\"status\":\"403\"}", "application/json");return;}
-    auto decoded_token = jwt::decode(json_body["token"]);
+    jwt::decoded_jwt<jwt::traits::kazuho_picojson> decoded_token = jwt::decode(json_body["token"]);
     std::string userid = "";
     for (auto& e : decoded_token.get_payload_json()) {
         if (e.first == "userId") {
@@ -20,7 +20,7 @@ void get_all_users(const httplib::Request& request, httplib::Response& response)
     nlohmann::json all_users = nlohmann::json::parse(usersfile);
     usersfile.close();
     nlohmann::json response_user_data = nullptr;
-    for (auto& user : all_users) {
+    for (nlohmann::json& user : all_users) {
         if (user["id"] == userid) {
             response_user_data = user;
         }
diff --git a/src/users/get_user.cpp b/src/users/get_user.cpp
index cc086e3..e2ced64 100644
--- a/src/users/get_user.cpp
+++ b/src/users/get_user.cpp
@@ -7,7 +7,7 @@ void get_user(const httplib::Request& request, httplib::Response& response) {
 
     if (json_body["token"] == nullptr) {response.set_content("{\"required\":\"[token]\"}", "application/json");return;}
     if (!verify_auth(json_body["token"])) {response.set_content("{\"status\":\"403\"}", "application/json");return;}
-    auto decoded_token = jwt::decode(json_body["token"]);
+    jwt::decoded_jwt<jwt::traits::kazuho_picojson> decoded_token = jwt::decode(json_body["token"]);
     std::string userid = "";
     for (auto& e : decoded_token.get_payload_json()) {
         if (e.first == "userId") {
@@ -20,7 +20,7 @@ void get_user(const httplib::Request& request, httplib::Response& response) {
     nlohmann::json all_users = nlohmann::json::parse(usersfile);
     usersfile.close();
     nlohmann::json response_user_data = nullptr;
-    for (auto& user : all_users) {
+    for (nlohmann::json& user : all_users) {
         if (user["id"] == userid) {
             response_user_data = user;
             break;