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API Response Builder

Design and build mock API responses with proper JSON structure. Choose status codes, configure headers, select response templates, and generate realistic sample data. Perfect for API prototyping and front-end development.

2xx Success Standard response for successful HTTP requests.

Response Headers

Response Body

Full Response Preview

HTTP/1.1 200 OK

About API Response Builder

This tool helps developers design and prototype API response structures before implementing them in a back-end service. Build realistic mock responses with proper HTTP status codes, headers, and JSON body structures. Use it for API documentation, front-end development, and team communication about API contracts.

Features

Frequently Asked Questions

What is a mock API response?
A mock API response is a simulated server response used during development and testing. It mimics the structure and data format of a real API, allowing front-end developers to build and test their applications without depending on a live back-end server.
What HTTP status codes should I use in my API?
Common status codes include: 200 OK for successful GET requests, 201 Created for successful POST/resource creation, 204 No Content for successful DELETE, 400 Bad Request for validation errors, 401 Unauthorized for missing authentication, 403 Forbidden for insufficient permissions, 404 Not Found for missing resources, and 500 Internal Server Error for unexpected server failures.
What headers should an API response include?
Essential API response headers include Content-Type (usually application/json), Cache-Control for caching behavior, X-Request-Id for request tracing, X-RateLimit headers for rate limiting info, and CORS headers like Access-Control-Allow-Origin. Security headers such as X-Content-Type-Options and Strict-Transport-Security are also recommended.
How should I structure paginated API responses?
A well-structured paginated response includes a data array with the results, and a meta object containing total count, current page, items per page, and total pages. Many APIs also include a links object with URLs for first, last, prev, and next pages, following HATEOAS principles for discoverability.

Learn More About API Design

REST API Design: Complete Guide

Best practices for designing RESTful APIs, status codes, versioning, and response structures.

HTTP Status Codes Explained

Every HTTP status code from 100 to 599 with practical usage examples.

Keyboard Shortcuts
Ctrl+Enter Run / Format
Ctrl+Shift+C Copy output
Ctrl+L Clear