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4 minute read - API Testing API Challenges

Challenge 21 - How To - POST todos create with JSON

Jul 17, 2021

This post and video shows how to complete the challenge POST /todos JSON to send a POST request to create a todo item with body and response in JSON format.

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POST /todos JSON

To create and amend items in a REST API we usually use a POST request. POST requests are defined as ‘partial’ requests in that they don’t need to have all the fields, but they need to have enough fields to be valid for the request.

Issue a POST request on the /todos end point to create a todo using Content-Type application/json, and Accepting only JSON ie. Accept header of application/json

For this challenge we issue a request with an accept header specifying JSON and we will send the message as JSON so we set the content-type header as well.

  • POST request means we will send information in the body of the message
    • e.g. POST /todos sends to the todos endpoint
  • create a todo means that we will not include a todo id, so a new todo is created
  • Content-Type application/json means set the content-type header to application/json because we are sending a JSON formatted message
  • Accept header of application/json means set the accept header to application/json so the response is formatted as JSON
  • the body of the message will have to be a valid todo item, and we can see the format in the documentation, or by issuing a GET request on the /todos endpoint
  • add the X-CHALLENGER header to track progress
  • we know it has been created when we receive a 201 response
  • the body of the response should contain the full details of the todo created in JSON format

Basic Instructions

  • First issue a GET request on “/todos” with an accept header of application/json to see the format of a todo in JSON format
  • Issue a POST request to end point “/todos”
    • if running locally that endpoint would be
      • http://localhost:4567/todos
    • if running in the cloud that endpoint would be
  • The request should have an Accept header with the value application/json because we want the response to be in JSON
  • The request should have an Content-Type header with the value application/json because our payload in the message is in JSON format
  • Use the todo that you copied from the GET request, remembering to remove the id because when we create a todo, it will be issued with an id automatically

We only need to use the minimum details, but could add a description if we wanted.

        "title": "create todo process payroll",
        "doneStatus": true,
        "description": ""
  • The request should have an X-CHALLENGER header to track challenge completion
  • The response status code should be 201 when all the details are valid.
  • Check the body of the response has JSON formatted ’todo’ response
    • this will contain the full details of the todo we created
  • Check the content-type header in the response has application/json matching the requested accept format


  • you might want to experiment with removing fields like ‘description’, what happens if you miss out fields?
  • check the Location header has the endpoint we can use to retrieve the todo, issue a GET on that endpoint to retrieve the details of the todo


> POST /todos HTTP/1.1
> Host:
> User-Agent: insomnia/2021.2.2
> X-CHALLENGER: x-challenger-guid
> Content-Type: application/json
> Accept: */*
> Content-Length: 106

|    {
|       "title": "create todo process payroll",
|       "doneStatus": true,
|       "description": ""
|     }

< HTTP/1.1 201 Created
< Connection: close
< Date: Sat, 17 Jul 2021 13:34:23 GMT
< Content-Type: application/json
< Location: todos/237
< Access-Control-Allow-Origin: *
< Access-Control-Allow-Headers: *
< X-Challenger: x-challenger-guid
< Server: Jetty(9.4.z-SNAPSHOT)
< Via: 1.1 vegur

Example Response body:

    "id": 237,
    "title": "create todo process payroll",
    "doneStatus": true,
    "description": ""

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