Each endpoint has an HTTP method and a path. Supported methods: GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS.

Paths start with / and can include path parameters prefixed with ::

/users
/users/:id
/projects/:projectId/tasks/:taskId

Path parameter values are available in your response body via {{params.id}}, {{params.projectId}}, etc.

Endpoints can be reordered by dragging, and removed with the delete button. You can have multiple endpoints with the same path but different methods.

Each response has the following settings:

• Status Code: any standard HTTP status (200, 201, 400, 404, 500, and so on)
• Content Type: JSON, plain text, HTML, or XML
• Custom Headers: key-value pairs sent with every response
• Body: the response body, with template variables for dynamic values

Example JSON response body:

{
  "id": "{{uuid}}",
  "name": "{{faker.person.fullName}}",
  "email": "{{faker.internet.email}}",
  "createdAt": "{{now}}"
}

To return a list, wrap part of the body in {{#repeat N}} and {{/repeat}}. The block renders N times, and Faker generates fresh values on each pass. Put the block between the array brackets and the helper adds the commas for you:

[
  {{#repeat 5}}
  {
    "id": {{index1}},
    "name": "{{faker.person.fullName}}",
    "email": "{{faker.internet.email}}"
  }
  {{/repeat}}
]

This returns an array of five users, each with its own data.

Inside a repeat you can use:

• {{index}} for the position, starting at 0 (or {{index1}} to start at 1)
• {{oneOf 'active' 'pending'}} to pick one option at random
• {{int 1 100}} for a random whole number in a range

The count can be a number, a range like {{#repeat 5 20}} (a random size between 5 and 20), or a query value like {{#repeat query.limit}}. Repeats can nest, so an item can hold its own list.

Set a delay in milliseconds on any response to mimic a slow network. It is useful for testing loading spinners, timeouts, and retry logic. The field sits next to the content type in the response editor.

Delays are capped at 10 seconds. The response is held for that long and then sent as usual.

Turn on Collection for a JSON response whose body is an array, and the endpoint answers query parameters the way json-server does. No extra setup, and it pairs well with a {{#repeat}} block that builds the rows.

GET /users?_page=2&_limit=10        page through results
GET /users?_sort=name&_order=desc   sort by a field
GET /users?role=admin               filter by an exact value
GET /users?age_gte=18               operators: _gte _lte _ne _like
GET /users?q=jane                   search across the whole item

The response includes an X-Total-Count header with the total before paging, and a Link header with first, prev, next, and last page URLs.

Import: paste an OpenAPI 3.x or Swagger 2.0 document (JSON or YAML), or a config you exported here, and the builder generates endpoints with Faker placeholders so they return fresh data. Replace your current setup or add to it.

Export from the toolbar in the format that fits where you are headed:

• Config (JSON): this builder's own format, re-importable here later
• OpenAPI spec: for Swagger UI and code generators
• Postman collection: a ready-to-send collection
• Mockoon environment: to run locally in Mockoon
• json-server db.json: seed data for a local json-server

Sharing: Click Share in the toolbar to copy the builder URL. The whole configuration is compressed into the URL, with no account or database. Anyone with the link can open and edit the mock API.

Base API URL: The toolbar shows the live API base URL. Append any endpoint path to make real HTTP requests. For example, if you defined GET /users, you can curl the base URL + /users.

Interactive Docs: Click Docs in the toolbar to open a Swagger-style documentation page for your mock API. It shows all endpoints, their methods, expected parameters, and response examples. Use the Test Request button to send live requests directly from the docs page.

If someone handed you a webtoolz mock API URL (even just the endpoint your app calls), you can open it in the builder to see and edit every route. The whole configuration lives in the URL, so there's nothing else to track down.

Paste it. On the builder with no endpoints, paste any mock URL (endpoint, docs, or builder link) into Have a mock API URL? and press open.

Or swap the path. The encoded segment is the same across every URL, so change /api/mock-api/ to /json/mock-api/ (and drop any request path after the encoded part) to open the builder, or to /json/mock-api/docs/ to read the docs:

Endpoint you have:
https://webtoolz.dev/api/mock-api/~a1b2c3d4e5f6g7h8/users

Open in the builder (swap the prefix, drop the path):
https://webtoolz.dev/json/mock-api/~a1b2c3d4e5f6g7h8

Read the docs:
https://webtoolz.dev/json/mock-api/docs/~a1b2c3d4e5f6g7h8

Or open it in a browser. Visiting the endpoint root shows an overview page with Open in Builder, View Docs, and OpenAPI spec links. Inspecting any response also works: the endpoint sends Link, X-Mock-Builder, and X-Mock-Docs headers pointing back here.

A short ~id link must still be resolvable (it was saved when the mock was shared); a longer link carries the entire config inline and always opens, even offline.