Zao Mock API

Install this WordPress plugin, then create a mock api response by sending query params. Simply make a GET/POST/PUT/ETC request to <site_url>?mock_api=1. This plugin is a great tool to help you mock your HTTP responses to test your REST API. Inspired by Mocky.

The Basics

By default, the status code will be 200, and the JSON body response will be:

{"success": true, "data": "Hello World"}

Mocking Responses

Both of those values can be modified with query parameters. For instance, making a request to <site_url>?mock_api=1&code=503&response[boolean]=1&response[string]=Hello World will return a status code of 503, and the JSON body response will be:

{"boolean": "1", "string": "Hello World"}

Managing Mock API access

If you want to modify if/how the mock api can be used, use the allow_mock_api filter.

Examples:

// Disable:
add_filter( 'allow_mock_api', '__return_false' );

// Allow for logged-in users only:
add_filter( 'allow_mock_api', 'is_user_logged_in' );

Probably wise to not install in production unless modifiying the allow_mock_api filter in some way.

Using Post/Term meta values as the API response

Along with the mock data functionality, you can also store mock data as post or term meta, and your API response will contain the meta value. To do so, you need to make a request to the permalink of the term/post with the ?mock_api=meta query parameter (e.g. <site_url>?mock_api=meta). If that post/term contains a meta value for the _mock_api meta key, that value will be returned in the data object:

{"success": true, "data": ["<meta value>"]}

If there is no meta value, you will still get a 200 response, but success will be false, with no data object:

{"success": false}

Again, this is for mocking API data only. If you want advanced meta REST API capabilities, consider CMB2.