Create a mock API

Updated October 18, 2026Free mock REST & WebSocket APIs

Paste or edit a JSON definition, click Publish, and get a live base URL. Resources become full REST endpoints; custom routes return exactly the status, headers and body you define.

Template

Mock definition (JSON)

{
  "name": "Todo app",
  "resources": [
    {
      "name": "users",
      "items": [
        {
          "id": 1,
          "name": "Ada Lovelace",
          "email": "ada@example.com"
        },
        {
          "id": 2,
          "name": "Alan Turing",
          "email": "alan@example.com"
        }
      ]
    },
    {
      "name": "todos",
      "items": [
        {
          "id": 1,
          "userId": 1,
          "title": "Write the first program",
          "completed": true
        },
        {
          "id": 2,
          "userId": 2,
          "title": "Break Enigma",
          "completed": false
        }
      ]
    }
  ],
  "routes": [
    {
      "method": "POST",
      "path": "/login",
      "status": 200,
      "body": {
        "token": "mock-token-123",
        "expiresIn": 3600
      },
      "delayMs": 300
    },
    {
      "method": "GET",
      "path": "/health",
      "status": 200,
      "body": {
        "status": "ok"
      },
      "delayMs": 0
    }
  ],
  "ws": {
    "echo": true,
    "onConnect": [
      {
        "type": "welcome"
      }
    ],
    "replies": [
      {
        "match": "ping",
        "reply": "pong"
      }
    ]
  }
}

✓ Valid — 2 resources, 2 custom routes, WebSocket script

How it works

Start from a template (todo app, e-commerce, blog, auth errors, realtime) or describe your API to the AI.
Edit resources and routes in the JSON editor — it validates as you type.
Publish, then click any endpoint to try it, or copy the curl command.

What every resource gives you

Request	Result
`GET /users`	List; filter with `?field=value`, `field_gte`, `field_lte`, `field_like`, `q`
`GET /users?_page=2&_limit=10`	Pagination with an `X-Total-Count` header
`GET /users?_sort=name&_order=desc`	Sorting
`GET /users/1`	One item, or 404
`GET /users/1/todos`	Related items by `userId`
`POST /users`	201 with the body plus the next id
`PUT / PATCH / DELETE /users/1`	Replaced / merged item / empty object

Custom routes and templating

Routes support :params, any method, status codes, headers and delays. String values can echo the request with {{params.id}}, {{query.page}} or {{body.email}}.

{ "method": "POST", "path": "/login", "status": 401,
  "body": { "error": "invalid_credentials", "email": "{{body.email}}" },
  "delayMs": 500 }

Related tools

Frequently asked questions

Is MockFox free?

Yes. No sign-up, no API key. Fair-use rate limits keep it fast for everyone, and clearly labeled sponsors pay for the servers.

Do POST, PUT and DELETE change the data?

No. Writes return realistic responses (a created item with a new id, a merged item for PATCH) but the stored data stays the same, so every test starts from a known state.

How long does a mock last?

30 days after the last save. Saving again extends it. Keep the edit key (it's stored in your browser) to update or delete the mock.

Can I simulate errors and slow responses?

Yes — add a custom route with any status code (401, 404, 429, 500…), custom headers and a delay up to 10 seconds.

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