Every request and response in our API is transmitted in JSON—JavaScript Object Notation. It’s simple to use and implementations of JSON are widely available. Where you see Data in these documents for POST, PATCH, and PUT requests, you must send data as JSON in the body of your request.

For example creating a task:


  "list_id": 12345,
  "title": "Hallo",
  "assignee_id": 123,
  "completed": true,
  "due_date": "2013-08-30",
  "starred": false


All requests that POST, PATCH, or PUT JSON must set a Content-Type header with a value of application/json. Not setting this header or setting it to a different value will result in an error.


All requests must be encoded using UTF-8. All responses are UTF-8.

Date and Time Format

All dates and times in the Wunderlist API are formatted as ISO-8601 strings. All times are provided as UTC. For example: 2013-10-09T23:34:11Z

Error Responses

Error responses are transmitted as an error dictionary and contain at least type, translation_key, and message attributes.

401 Unauthorized

  "error": {
    "type": "unauthorized",
    "translation_key": "api_error_unauthorized",
    "message": "You are not authorized."

404 Not Found

  "error": {
    "type": "not_found",
    "translation_key": "api_error_not_found",
    "message": "The resource you requested could not be found."

400 Bad Request

Additional attributes may be sent with some errors. In particular, for bad requests with a message of Missing parameter., the missing parameters along with messages indicating the problem are provided.

  "error": {
    "type": "missing_parameter",
    "translation_key": "api_error_missing_params",
    "message": "Missing parameter.",
    "list_id": ["required", "can't be blank"]
You can report issues or ask questions via our GitHub repository.