diff --git a/include/mastodont_fetch.h b/include/mastodont_fetch.h
index cd7d915..a546407 100644
--- a/include/mastodont_fetch.h
+++ b/include/mastodont_fetch.h
@@ -71,7 +71,7 @@ int mstdnt_fetch_curl_async(mastodont_t* mstdnt,
                             struct mstdnt_args* args,
                             mstdnt_request_cb_t cb_request,
                             void* cb_args,
-                            int (*json_cb)(cJSON*, void*),
+                            int (*json_cb)(cJSON*, void*, mstdnt_request_cb_data*),
                             void* json_args,
                             char* url,
                             CURLoption request_t,
diff --git a/include/mastodont_types.h b/include/mastodont_types.h
index 0c8a9ac..8933037 100644
--- a/include/mastodont_types.h
+++ b/include/mastodont_types.h
@@ -30,7 +30,7 @@ typedef int8_t mstdnt_bool;
 
 struct mstdnt_storage;
 
-typedef void (*mstdnt_data_free_cb_t)(void*, size_t);
+typedef void (*mstdnt_data_free_cb_t)(void*);
 
 typedef struct mstdnt_request_cb_data {
     struct mstdnt_storage* storage;
@@ -38,7 +38,7 @@ typedef struct mstdnt_request_cb_data {
     mstdnt_data_free_cb_t data_free_cb;
 } mstdnt_request_cb_data;
 
-typedef void (*mstdnt_request_cb_t)(mstdnt_request_cb_data* data, void* args);
+typedef int (*mstdnt_request_cb_t)(mstdnt_request_cb_data* data, void* args);
 
 // Return types for mstdnt_request_cb_t, specifies
 //  what we want to do with the data
diff --git a/src/fetch.c b/src/fetch.c
index 10a4973..61de5e2 100644
--- a/src/fetch.c
+++ b/src/fetch.c
@@ -52,7 +52,7 @@ int mstdnt_fetch_curl_async(mastodont_t* mstdnt,
                             struct mstdnt_args* m_args,
                             mstdnt_request_cb_t cb_request,
                             void* cb_args,
-                            int (*json_cb)(cJSON*, void*),
+                            int (*json_cb)(cJSON*, void*, mstdnt_request_cb_data*),
                             void* json_args,
                             char* _url,
                             CURLoption request_t,