ReqRes | Free REST API for developers | ReqRes

# ReqRes - Backend platform for frontend developers and AI agents > ReqRes is a backend you call with fetch(). Collections, auth, logs, automations, and a sandbox for AI coding agents. No servers to run. ## For LLMs building against ReqRes Full API reference (JSON): https://reqres.in/llm.json Full API reference (text): https://reqres.in/llm.txt OpenAPI spec: https://reqres.in/openapi.json ## Quick context ReqRes has three API surfaces: 1. Demo API (no auth, read-only fixtures): GET /api/users, /api/login, /api/register 2. Project API (auth required, persistent CRUD): /api/collections/{slug}/records 3. Agent Sandbox (no auth, deterministic fixtures): /agent/v1/users, /agent/v1/orders, /agent/v1/scenarios/* New users get a free project with a "products" collection (name, price, category, in_stock). ## Auth patterns - Demo endpoints: no auth needed - Project reads: x-api-key header (public key, pub_* prefix, browser-safe) - Project writes: x-api-key header (manage key, pro_* prefix, server-side only) - App user endpoints: Authorization: Bearer <session_token> (from magic link flow) - Agent Sandbox endpoints: free tier is open (no header), 100 req/day per IP. Paid tier sends `x-agent-id: agt_<64 hex>` (issued at app.reqres.in/agents only - arbitrary strings return 401) ## Critical: request body format POST and PUT to /api/collections/* require the body wrapped in a "data" object: {"data": {"name": "Example", "price": 9.99}} Sending fields at the top level without "data" returns 400. ## Agent Sandbox conventions - IDs: ULID with type prefix (usr_, ord_, prd_, etc.). 26 chars after underscore. - Timestamps: ISO 8601 with millisecond precision, always UTC (.000Z). - Money: object {amount: integer_smallest_unit, currency: "USD", formatted: "$59.99"}. - Pagination: cursor-based (meta.next_cursor); pass cursors back unchanged. - Caching: data endpoints max-age=60, scenario endpoints no-store. - Deterministic: same (seed, cursor) inputs always return identical

{"openapi":"3.0.3","info":{"title":"ReqRes API","description":"OpenAPI specification for the ReqRes API. Covers legacy demo endpoints, collections, app-user auth flows, custom endpoints, and the Agent Sandbox (/agent/v1/*) for AI coding agents. All /api/* endpoints require x-api-key. All /app/* endpoints require Authorization: Bearer <session_token>. /agent/v1/* endpoints are open in v1 (IP-based rate limiting).","version":"2.1.0","contact":{"name":"ReqRes Support","url":"https://reqres.in","ema