Mock APIs#

What is a mock API?#

Create fully functional API endpoints without server-side code. Define endpoints, set response bodies with dynamic data, and share a working API URL with your team.

Mock endpoints are served at:

https://mocklane.com/m/{workspace-short-id}{path}

# Example:
GET https://mocklane.com/m/abc-xyz/api/users
GET https://mocklane.com/m/abc-xyz/api/users/42

How do I create a mock API endpoint?#

1. 1Navigate to your workspace → Mocks tab.
2. 2Click New Mock.
3. 3Set the HTTP method (GET, POST, PUT, PATCH, DELETE).
4. 4Set the path (e.g., /api/users or /api/users/:id).
5. 5Click Create to open the editor.

Response Body & Status#

Configure the response consumers will receive:

• Status Code — 200, 201, 404, 500, etc.
• Response Headers — Custom headers (Content-Type defaults to application/json).
• Response Body — JSON with optional template variables.
• Response Delay — Simulate latency in milliseconds.

How do I generate dynamic response data?#

Embed dynamic generators in your JSON response using {{...}} syntax. Each call produces fresh random values.

{
  "id": "{{randomUUID}}",
  "name": "{{faker.fullName}}",
  "email": "{{faker.email}}",
  "age": "{{randomInt 18 65}}",
  "avatar": "{{faker.avatar}}",
  "joined": "{{now}}",
  "address": {
"city": "{{faker.city}}",
"country": "{{faker.country}}"
  }
}

Each request returns unique data:

{
  "id": "550e8400-e29b-41d4-a716-446655440000",
  "name": "Emma Johnson",
  "email": "emma.johnson@example.com",
  "age": 34,
  "avatar": "https://i.pravatar.cc/150?u=550e8400",
  "joined": "2026-04-12T10:30:00Z",
  "address": {
"city": "San Francisco",
"country": "United States"
  }
}

Generator Reference#

MockLane includes 121 built-in generators, plus direct access to any Faker method via {{faker.method()}}. Use the Template Helper picker in the editor or type them manually.

How do I return different responses for different requests?#

Return different responses based on the incoming request. Each rule has its own status code, headers, and body.

Match conditions can test against:

• Headers — e.g., when Authorization contains "Bearer".
• Query Parameters — e.g., when status=active.
• Body Fields — e.g., when type equals "premium".
• Path Parameters — e.g., when :id equals "404".

Rules are evaluated in priority order. First match wins. If none match, the default response is returned.

How do I change the response on each call?#

Define a series of responses returned in order, one per request. Useful for simulating state changes:

Step 1 → 200 {"status": "pending"}
Step 2 → 200 {"status": "processing"}
Step 3 → 200 {"status": "completed"}
     ↩ loops back to Step 1

When Loop is enabled, the sequence restarts after the last step. Otherwise, the last step repeats indefinitely.

How do I serve a JSON file as an API?#

Put a JSON array on the endpoint's Static Data tab and it serves that array, filtered by exact-match query parameters such as ?role=admin:

Immutable Mode#

Enable Immutable Mode to restrict an endpoint to GET requests only. All write methods return 405 Method Not Allowed. Useful for exposing read-only data.

How do I simulate API errors and failures?#

Test error handling by configuring:

• Error Rate — Percentage of requests that return an error (0–100%).
• Error Status — HTTP status code for errors (e.g., 500, 503).
• Error Body — Custom JSON body for error responses.

Example: set 20% error rate with 503 status to simulate intermittent outages.

Mock URL#

Every mock endpoint has a live URL displayed at the top of the editor. Use it in your frontend, mobile app, or any HTTP client:

# cURL
curl https://mocklane.com/m/abc-xyz/api/users

# JavaScript
const res = await fetch("https://mocklane.com/m/abc-xyz/api/users");
const data = await res.json();

# Python
import requests
r = requests.get("https://mocklane.com/m/abc-xyz/api/users")
data = r.json()