API response is JSON formatted and it has Content-Type: application/json header.

HTTP status codes

MailerLite uses standard HTTP response codes.

HTTP code

Description

200

OK

The request succeeded.

201

Created

The request was fulfilled and resulted in a new resource being created.

204

No Content

The server fulfilled the request but does not need to return an entity-body, i.e. when resource is deleted.

400

Bad Request

The request could not be understood by the server due to malformed syntax.

401

Unauthorized

The request requires user authentication.

404

Not Found

The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.

500

Internal Server Error

The server encountered an unexpected condition which prevented it from fulfilling the request.

Response with error

Every error has the structure described below.

Parameter

Type

Description

error

Object

Object that contains data about error

error.code

Integer

Optional Code of error

error.message

String

Readable message about the error occurred

{
  "error": {
    "code": 123,
    "message": "Group not found"
  }
}

API error codes

Error code

Message

Description

1

Unauthorized

API key is required and is not provided

2

Endpoint not found

The endpoint you are trying to use is non-existing

302

API-Key Unauthorized

You are trying to use an invalid API key to authorize

429

Too many requests

You reached the API rate limit