diff --git a/api/schema.lua b/api/schema.lua
index 6566bdc..82c45eb 100644
--- a/api/schema.lua
+++ b/api/schema.lua
@@ -8,26 +8,12 @@ local http, url = ...
 -- @param create_schema the new schema as table
 -- @return a promise with the result
 function blockexchange.api.create_schema(token, create_schema)
-  return Promise.new(function(resolve, reject)
-    local json = minetest.write_json(create_schema);
-    http.fetch({
-      url = url .. "/api/schema",
-      extra_headers = {
-        "Content-Type: application/json",
-        "Authorization: " .. token
-      },
-      timeout = 10,
-      method = "POST",
-      data = json
-    }, function(res)
-      if res.succeeded and res.code == 200 then
-        local schema = minetest.parse_json(res.data)
-        resolve(schema)
-      else
-        reject(res.code or 0)
-      end
-    end)
-  end)
+  return blockexchange.api.json({
+    endpoint = "schema",
+    data = create_schema,
+    method = "POST",
+    token = token
+  })
 end
 
 --- updates the stats of an existing schema
diff --git a/api/util.lua b/api/util.lua
new file mode 100644
index 0000000..d3bb90c
--- /dev/null
+++ b/api/util.lua
@@ -0,0 +1,36 @@
+---------
+-- api utilities
+
+local http, url = ...
+
+function blockexchange.api.json(opts)
+    return Promise.new(function(resolve, reject)
+        local extra_headers = {
+            "Content-Type: application/json"
+        }
+
+        if opts.token then
+            table.insert(extra_headers, "Authorization: " .. opts.token)
+        end
+
+        http.fetch({
+            url = url .. "/api/" .. opts.endpoint,
+            extra_headers = extra_headers,
+            timeout = opts.timeout or 10,
+            method = opts.method or "GET",
+            data = opts.data and minetest.write_json(opts.data)
+        }, function(res)
+            if res.succeeded and res.code == 200 then
+                local obj = minetest.parse_json(res.data)
+                resolve(obj)
+            else
+                local obj
+                if res.data and res.data ~= "" then
+                    -- TODO: data is empty if the status-code is 400 :/
+                    obj = minetest.parse_json(res.data)
+                end
+                reject(res.code or 0, obj)
+            end
+        end)
+    end)
+end
\ No newline at end of file
diff --git a/commands/save.lua b/commands/save.lua
index 878c086..506e7ab 100644
--- a/commands/save.lua
+++ b/commands/save.lua
@@ -62,7 +62,10 @@ function blockexchange.save(playername, pos1, pos2, name, local_save)
 			-- start save worker with context
 			blockexchange.save_worker(ctx)
 		end):catch(function(http_code)
-			local msg = "[blockexchange] create schema failed with http code: " .. (http_code or "unknown")
+			local msg = "[blockexchange] create schema failed with http code: " ..
+				(http_code or "unknown") ..
+				", you might have exceeded the upload limits"
+
 			minetest.log("error", msg)
 			minetest.chat_send_player(playername, minetest.colorize("#ff0000", msg))
 			ctx.promise:reject(msg)
diff --git a/init.lua b/init.lua
index 80fb64b..752ede3 100644
--- a/init.lua
+++ b/init.lua
@@ -27,6 +27,7 @@ end
 
 -- http api
 if blockexchange.is_online then
+	loadfile(MP.."/api/util.lua")(http, blockexchange.url)
 	loadfile(MP.."/api/info.lua")(http, blockexchange.url)
 	loadfile(MP.."/api/schema.lua")(http, blockexchange.url)
 	loadfile(MP.."/api/schemapart.lua")(http, blockexchange.url)