diff --git a/README.md b/README.md
index ddc81a7..a76b06a 100644
--- a/README.md
+++ b/README.md
@@ -99,21 +99,70 @@ The following example is format usually used for failed response with status cod
 }
 ```
 
-For returning multiple validation problems, here's the example:
+For returning multiple validation problems, it **MUST** return error messages inside an array. Inside the `errors` array **MUST** contain the following element:
+- `key` : taken from request body's property that doesn't pass the validation
+- `value`: is the validation error message
+
+Here's the example for multiple validation problems:
 ```
 {
     "success": false,
     "error-code": null, /* or optional error payload, eg: 3001, 3002, etc. */
     "errors": [
-        "The email must be a valid email",
-        "The password must be at least 6 chaarcters",
-        "The phone number is already used"
+        "email": "The email must be a valid email",
+        "password": "The password must be at least 6 chaarcters",
+        "phone": "The phone number is already used"
     ],
     "message": "Error xyz has occurred"
 }
 ```
 
 ## HTTP Response Code
+HTTP response status code indicate whether a specific HTTP request hasbeen successfully completed. There are 3 types of response code usually used:
+- Successful response (`2xx`)
+- Client errors (`4xx`)
+- Server errors (`5xx`)
+
+### Successful Responses (`2xx`)
+**200 OK**
+
+The request has succeeded. The meaning of the success depends on the HTTP method:
+- `GET`: The resource has been fetched and is transmitted in the message body.
+- `PUT or POST`: The resource describing the result of the action is transmitted in the message body.
+
+**201 Created**
+
+The request has succeeded and a new resource has been created as a result. This is typically the response sent after `POST` requests, or some `PUT` requests.
+
+### Client Error Responses (`4xx`)
+**400 Bad Request**
+
+The server could not understand the request due to invalid syntax.
+
+**401 Unauthorized**
+
+Although the HTTP standard specifies "unauthorized", semantically this response means "unauthenticated". That is, the client must authenticate itself to get the requested response.
+
+**404 Not Found**
+
+The server couldn't find requested resource. This can be the URL / endpoint or the data that client looking for is not exists.
+
+**405 Method Not Allowed**
+
+The request method is known by the server, but has been disabled and cannot be used. For example:
+> An endpoint `/users/1` must be requested using `GET` HTTP verb, but we access it using `POST` HTTP verb.
+
+According to the case above, the server will return a response with the `405` status code.
+
+### Server Error Response (`5xx`)
+**500 Internal Server Error**
+
+This means that the server has encountered a situation it doesn't know how to handle. For example when a failure occurred in deleting data.
+
+**502 Bad Gateway**
+
+This error response means that the server, while working as a gateway to get a response needed to handle the request, got an invalid response. Or in short, when our server is down.
+
 ## Error Code
 ## Panduan Kontribusi