ReqRes compared to Postman

ReqRes and Postman are complementary tools, not competitors. Postman is an API client for sending requests and testing; ReqRes is the backend surface you test against. Understanding how they work together helps you build better testing workflows.

TL;DR

• Postman is an API client for sending HTTP requests, testing APIs, and documenting endpoints.
• ReqRes is a backend that provides the endpoints you test against-collections, app users, auth, and logs.
• Postman needs an API to call; ReqRes gives you one instantly.
• Use them together: create a ReqRes project, import endpoints into Postman, test your data flows.

What ReqRes is

ReqRes is a frontend-first backend you call with fetch(). When you create a project, you get:

• Collections - REST endpoints for your JSON data (/api/:collection)
• App users - Magic-link authentication endpoints
• Request logs - Every API call recorded and viewable
• Custom endpoints - Define specific responses for mocking
• Triggers - Webhooks and automations on data changes

ReqRes is the server; it receives and responds to HTTP requests. Your frontend (or Postman) is the client.

What Postman is

Postman is an API client and collaboration platform. It provides:

• HTTP client - Send GET, POST, PUT, DELETE requests with a GUI
• Collections - Organize and save requests for reuse
• Environments - Manage variables across different setups
• Testing - Write assertions and run automated test suites
• Documentation - Generate API docs from your collections
• Mock servers - Return predefined responses for development

Postman helps you interact with APIs; it doesn't provide the API itself.

Key differences

When to choose ReqRes

You need ReqRes when you:

• Need a real backend to test against, not just a mock server
• Want persistent data that survives between requests
• Build frontend apps and need actual API endpoints
• Run QA automation with realistic data flows (create → read → update → delete)
• Demo features with working data, not static responses
• Learn REST/HTTP with a real server that behaves like production

Example scenarios:

• Testing a React app's data fetching and state management
• Running end-to-end tests that create, modify, and verify data
• Demonstrating API-driven features to stakeholders
• Teaching REST concepts to junior developers

When to choose Postman

You use Postman when you:

• Test existing APIs - Send requests to any HTTP endpoint
• Debug API responses - Inspect headers, status codes, body
• Automate testing - Write test scripts that run on responses
• Document APIs - Generate docs from request collections
• Share requests - Collaborate on API testing with your team
• Mock temporarily - Stub responses while backend is unavailable

Example scenarios:

• Debugging why a third-party API returns unexpected data
• Building a test suite for your production API
• Sharing API examples with frontend developers
• Generating documentation for internal APIs

Using ReqRes + Postman together

The most powerful workflow combines both tools.

Step 1: Create a ReqRes project

Create a project at app.reqres.in and note your API key.

Step 2: Import into Postman

Create a Postman collection with requests to your ReqRes endpoints:

GET    {{baseUrl}}/api/tasks
POST   {{baseUrl}}/api/tasks
GET    {{baseUrl}}/api/tasks/:id
PUT    {{baseUrl}}/api/tasks/:id
DELETE {{baseUrl}}/api/tasks/:id

Set environment variables:

• baseUrl: Your ReqRes project URL
• apiKey: Your ReqRes API key

Step 3: Test data flows

Use Postman to:

• Create records and verify responses
• Fetch lists with filters and pagination
• Update records and confirm changes
• Delete records and test error handling

Step 4: Write assertions

Add Postman tests to verify ReqRes responses:

pm.test('Status is 200', () => {
    pm.response.to.have.status(200)
})

pm.test('Response has data array', () => {
    const json = pm.response.json()
    pm.expect(json.data).to.be.an('array')
})

pm.test('Created record has id', () => {
    const json = pm.response.json()
    pm.expect(json.data.id).to.exist
})

Step 5: Automate

Run your Postman collection with Newman (CLI) as part of CI/CD. ReqRes provides consistent, resettable data for reliable test runs.

ReqRes is not for you if...

• You only need to test third-party APIs (use Postman alone)
• You have an existing backend with its own API
• You need GraphQL endpoints (ReqRes is REST-only)
• You just want to document APIs without testing them

Common questions

Can Postman mock servers replace ReqRes?

Partially. Postman mock servers return predefined responses, but they don't persist data between requests. If you POST a new record, a subsequent GET won't include it. ReqRes persists data, making it suitable for realistic data flow testing.

Do I need Postman if I use ReqRes?

Not necessarily. You can test ReqRes directly from your browser, frontend code, or curl. Postman adds value for:

• Organized request collections
• Team collaboration
• Automated test suites
• API documentation

How do request limits work?

ReqRes limits are per project (requests/day, stored records). Postman sends requests through its client, so there's no Postman-side limit on calls to ReqRes. Your ReqRes plan determines how many requests you can make.

Can I use ReqRes as a mock server?

Yes. ReqRes custom endpoints let you define specific paths and responses. Unlike Postman mocks, ReqRes custom endpoints are served from a real URL your frontend can call in development and staging.

Example workflow: Testing a task manager

Here's how a QA engineer might use both tools:

1. Create ReqRes project with a tasks collection
2. Set up Postman collection with CRUD endpoints
3. Write test scenarios:
   • Create task → verify 201 response and returned ID
   • List tasks → verify new task appears
   • Update task status → verify changes persist
   • Delete task → verify 204 response
   • List tasks → verify task is gone
4. Run in CI with Newman, reset ReqRes data between runs

This gives you real data persistence, observable logs, and repeatable tests.

Next step

Create a ReqRes project and import the endpoints into Postman. See how real data persistence improves your API testing workflow.

• Try ReqRes Projects - Create your first project
• See Notes example - Explore a working app