How to complete the challenge `GET /api/todos (200) ? filter description regex`

By Alan RichardsonPublished 2026-07-31

How to issue a GET request on a top level entity endpoint and filter todos by matching the description with a regular expression.

GET /api/todos (200) ? filter description regex

Issue a GET request on the /api/todos end point with a regular expression filter on description that returns todos with non-empty descriptions, requesting the response in JSON format.

description~=.*fixture.* means return todos where the description matches the regular expression
most tools and browsers will encode any reserved characters for you when sending the request
the response should contain at least one todo
every returned todo should have a non-empty description
every returned description should match the regular expression
the returned todo list should be JSON, so send Accept: application/json if the response is not JSON

Basic Instructions

Create or update a todo so it has a description containing fixture
Issue a GET request to end point "/api/todos"
- https://apichallenges.com/api/todos
The request should have an X-CHALLENGER header to track challenge completion
The request should have an Accept: application/json header so the API returns todos in JSON format
Add a regular expression filter:
- https://apichallenges.com/api/todos?description~=.*fixture.*
The response status code should be 200 because the request is accepted
Check that every returned description is non-empty and contains fixture

Try it now

If you need a matching todo, create one with a non-empty description containing fixture. See the solution.

POST /api/todos to create a regex filter fixture

Filter by regular expression:

GET /api/todos?description~=.*fixture.* to filter descriptions by regex

Example Request

> GET /api/todos?description~=.*fixture.* HTTP/1.1
> Host: apichallenges.com
> User-Agent: rest-client
> X-CHALLENGER: x-challenger-guid
> Accept: application/json

Example Response

< HTTP/1.1 200 OK
< Connection: close
< Content-Type: application/json
< X-Challenger: x-challenger-guid

Returned body:

{
  "todos": [
    {
      "id": 8,
      "title": "regex filter fixture",
      "doneStatus": false,
      "description": "created fixture for regex filter"
    }
  ]
}

Lessons Learned

The description~= query uses a regular expression match, which is more expressive than exact filtering.
Regex filters need fixture data with predictable text so the assertion is meaningful.
Reserved characters in regex query values may be encoded by clients before transmission.

Suggested Experiments

Change description~=.*fixture.* to anchor the match, such as ^created, and compare returned todos.
Add a todo whose description nearly matches and confirm the regex includes or excludes it as expected.

Experiment with this endpoint

How to complete the challenge GET /api/todos (200) ? filter description regex