What free mock REST API can students practise API testing against with zero setup?

ReqRes (reqres.in) is a live REST API students can call from any browser or terminal with no signup and no key. It has real endpoints for listing, creating, updating and deleting users, real auth flows (register, login, tokens), and deliberate error responses (404, 400, 429, 500) so students can practise the unhappy paths too. Because it is hosted, nobody has to run a backend, install anything, or configure a database to start the lesson.

How do I run ReqRes for a whole class?

A ReqRes classroom gives each student their own isolated data in your class project, so it never collides with a classmate's, plus a roster so you can see who is set up. One class of up to 30 students is free: students join with their own free ReqRes account using your class link. Classroom plans add more classes and students, with regional pricing for your country.

Do students need to sign up or install anything?

No. The public API at reqres.in works keyless from the browser or curl, so a first lesson can be a single fetch() call with nothing to install. When you want each student to build and persist their own collections, a free account or the Classroom plan adds that, still with no local backend.

Can students practise authentication and error handling, not just GET requests?

Yes. ReqRes exposes register and login endpoints that return real tokens and real 400s on bad input, full CRUD (POST, PUT, PATCH, DELETE) with correct status codes, and deliberate failures (404 not found, 429 rate limited, 500 server error) so students learn to read status codes and handle failures, not just the happy path.

For teaching REST and API testing

The zero-setup API your class can practise against

Teaching REST or API testing means every student needs a working backend, and setup eats the lesson. ReqRes is a live API students call from any browser, no signup, no install. Real endpoints, real auth, real error codes to practise on.

Try a request now Run it for a class

The public API is free and keyless. A classroom for one class of up to 30 students is free too: students join with a link.

The backend is the part that eats the lesson.

You want to teach HTTP verbs, status codes, JSON, auth, and how to test an API. Instead the first hour goes to installing Node, running a server, fixing a port conflict on one laptop, and a database that will not start on another. Half the class is stuck before anyone has made a request.

ReqRes removes the backend from the equation. It is a real, hosted API. A student opens a browser or a terminal and makes a request that actually works, on the school network, on a Chromebook, on a phone. The lesson is the API, not the setup.

A first lesson in one line

No signup, no key. Every student can run this on day one and get a real JSON response back:

curl https://reqres.in/api/users/2

Then the unhappy path, so they learn to read status codes, not just bodies:

curl -i https://reqres.in/api/users/23   # 404
curl -i -X POST https://reqres.in/api/register \
  -H "Content-Type: application/json" \
  -d '{"email":"eve.holt@reqres.in"}'      # 400, missing password

There is an interactive version right on the homepage: pick an endpoint, hit send, read the real response. Nothing to install.

Everything an API testing unit needs to cover

GET, POST, PUT, PATCH, DELETE

Full CRUD with correct status codes (200, 201, 204). Students learn each verb against responses that behave the way the spec says they should.

Real auth flow with tokens on success and 400s on bad input, so an auth lesson is a live demo, not a diagram.

404, 400, 429, 500

Deliberate failures to assert against. Testing is mostly the unhappy path, and here it is on tap.

pagination and delays

Paged list responses and a delay parameter, so students exercise pagination and client-side timeouts in an exercise, not a lecture.

Works from any client the course already uses: fetch(), curl, Postman, Playwright, Python requests, Java, C#.

Run it for a whole class

The shared demo API is enough for early lessons. When you want each student to build and persist their own data, create a classroom: every student gets their own isolated data so it never collides with a classmate's, and a roster shows you who is set up.

One class of up to 30 students is free. Share your class link and students join with their own free ReqRes account, each with their own key. For more classes or larger cohorts, Classroom plans have regional pricing, so they're priced for a classroom in your country, not a company.

Create a free classroom More for educators

Why not a local server or a static mock?

Need	Run a backend / static mock	ReqRes
Student setup on day one	Install Node, run a server, fix ports	Open a browser, make a request
Practise error codes	JSONPlaceholder returns 200 forever	404, 400, 429, 500 on demand
Auth flow to test	Build it yourself	register / login with real tokens
Each student their own data	One shared server or many to manage	Isolated project per student (Classroom)
See who is set up	Ask around	Roster view

Start your next lesson without the setup

The public API is free and keyless. When students need their own data, create a free classroom and share the link.

Get started free ReqRes for educators