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API Practice Sites

There are many lists of 'free to use' APIs online. Most of these are not designed for practicing testing or automating. I have listed a few collation sites at the bottom of this page.

All of the sites and applications listed here are designed for practice. This carefully curated list only presents the best applications to use to improve your testing and automating.

Online and Free to Use

API Simulators

API Simulators provide end points, and simulate a functional API in that the information is hard coded or randomly generated and no create, update or delete action will persist to the server (POST, PUT, DELETE, PATCH).

Simulators are a good place to start, and practice with tooling. But do not stay with them too long. Try to move on to Real APIs and applications quickly so you get the experience of controlling the data in the system through API Interaction.

There are many API simulators so we have only listed a few of the best here.

API Challenges Simulator

API Challenges Simulator

  • An API Simulator (i.e. it always response the same way and you can't update data on the back-end, but the system will respond as though you did.
  • Follow the instructions on the linked page and issue GET, POST, PUT and DELETE requests.

HTTPBin

httpbin.org

  • This API can help you get used to your tools.
  • It has a set of endpoints that you can call for documented outcomes.
  • e.g. a DELETE call to https://httpbin.org/delete/404 will return payload, using any other verb will return a 405 Method Not Allowed status code.
  • I think it is a useful exercise to work through all the API endpoints through the Swagger interface, make sure you know what they do, and then replicate the request through an API client. This should be a useful way of getting used to the functionality in your API client.

JSON Placeholder

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  • An API For GET requests.
  • Acts as a simulator for Update and Delete requests
  • Useful for getting used to your REST Client Tooling.
  • notable for the usage guide showing example usages as JavaScript that you can run from the Browser Developer Tools console. This can be a useful approach to experiment when exploring and testing a system.

Dummy JSON

dummyJSON

  • An API for JSON requests and responses.
  • A lot of endpoints for different types of data.
  • Supports filters and limits as URL Query parameters.
  • Simulate Update requests (POST, PUT, DELETE)

Fake REST API

Fake REST API

  • Another simulator with a Swagger front end to experiment easily, but do make sure to use a REST Client as well.
  • The POST and PUT requests don't update the server but they are validated so you can see an additional approach to JSON validation error reporting.
  • Even as a simulator it has bugs so you can explore the functionality and find issues.

GET Only APIs

These APIs are full APIs, but they will only respond to GET requests. This usually also means they support OPTIONS and HEAD requests. They are typically not designed for practicing testing but they can be an easy option for getting used to your REST API Client tooling.

Additionally they often have a lot of data so can support Query parameters for filtering, pagination and limiting data. Read the documentation for each API and experiment in your chosen REST Client.

Swapi Star Wars API

swapi the Star Wars API

  • read our longer write up with exercises to try here
  • A GET based API (no updates allowed) with a variety of data end points
  • All endpoints return star wars information
  • The UI can help you get started but make sure to use a REST Client on the API to get used to your tooling.
  • HEAD and OPTIONS are also supported

Random User Me

Random User Me

  • A GET based API for returning random user details.
  • Useful for experimenting with Query parameters to filter, paginate and download
  • returns a random User, supports different formats but this is controlled by a format URL parameter rather than an Accept header, which is a pity, but having different formats can help you practice with additional data formatting and parsing tooling.
  • There is no Swagger spec so you can use this as an exercise in modelling the API by hand.

Others

  • pokeapi.co - like swapi.dev but for Pokemon data

Full APIs

These are full APIs online, which means you don't have to install anything and can persist data on the server so PUT, POST, PATCH, DELETE are usually supported. These APIs usually have the additional step of creating an authentication key or registering a session but the instructions will usually walk you through this.

Toolshop API

Toolshop API by Roy de Kleijn

  • Toolshop API has a UI and an API backend. This allows you to experiment with the UI, open the network tab and see the relevant API requests, or use the API and double-check the results on screen in the UI.
  • Multiple versions of the Toolshop are available.
    • A deliberately buggy version is available if you want to explore for issues.
    • The Main Version where bugs are not intended, or perhaps not perceived as bugs, remember every API is different.
  • The Open AI Swagger file is one of the most complete that I've seen, and is a great example of the capabilities of the format.
  • The Toolshop API allows GET,POST, PUT methods without authentication.
  • Some endpoints require that you master the authentication process which requires logging in as a user, then using the returned token as an HTTP Bearer Token.
  • The DELETE endpoints seemed to require logging in as an admin user.
  • The admin user also receives 'more' data in the responses, so its worth experimenting with the different users.
  • The Database is shared, so don't add any private information (e.g. your name and email) if you create a new user.
  • The error messages returned from the server in the message are useful aids to helping you craft a valid payload.

API Challenges

API Challenges

  • Our API Challenges is a fully functional TODOs management application.
  • Create a session by issuing a POST request to https://apichallenges.eviltester.com/challenger, you will see an X-CHALLENGER header in the response and if you add that header into all your requests you will be able to update data and view your solved challengs progress in the UI.
  • It is not deliberately buggy so if you experience problems, you've either found a bug or still have to learn to use the HTTP Client tooling.
  • There are 50+ challenges to complete which will guide you through an API testing process.
  • Since it is a working API you can make up your own challenges and try whatever tests you want.

GO Rest

Go REST

  • A functional API that persists data to the server in a shared session so do not use any private data or personal information.
  • To use the PUT, POST, PATCH, DELETE request you need to request an access token by logging in using Github, Google or Microsoft. Then add this as a Bearer token in your request.
  • It performs data validation, reporting all errors in the response making it easy to work with.
  • The documentation is not automatically generated which is good. You have to read the docs, and model the API then experiment with it.
  • No swagger file is provided so you create the request collection as you test.
  • After reading the documentation and performing some tests I did find a difference between the docs and the implementation so I don't think the system is bug free, which makes it a test application as well as a practice application.
  • Also provides a GraphQL endpoint, which I haven't experimented with.

Expand Testing Notes API

Notes API from Expand Testing

  • I'm not sure if the API is supposed to be deliberately buggy or not since it comes from a Testing company it might be. But keep your eyes open for inconsistencies when testing.
  • It provides a swagger UI interface, but remember to go beyond that and use a REST Client.
  • It is interesting to see alternative approaches in an API e.g. seeing an Options response that is human-readable (this approach is also used in Restful Booker).
  • You need to 'register', then 'login', find the token and then pass this in as a X-AUTH-TOKEN to use the API properly. By doing this your data is saved separate from other users, which means you will find testing easier as no-one else is interfering with your test data.
  • There is a UI that uses the API so experiment with this and vew the API calls in the network tab.

APIs Not for First Time Use

I found the following APIs to be buggy, either deliberately or not. So I wouldn't recommend them as your first API to practice with. Once you are confident with how APIs work, and understand the tooling, then I'd recommend testing with them.

Restful Booker

Restful Booker

  • A deliberately buggy REST API.
  • The bugs can make it hard to identify if you are doing something wrong, so I wouldn't start with this one, use this only after you've practiced with some more functional APIs. Otherwise you risk confusing yourself or thinking that your tools are not working correctly.
  • Once you've explored a few APIs then this is worth working through. It is designed to be used in an API Training course so adding 'bugs' in the app works well in that scenario because an instructor can guide you through the issues and answer questions.

Swagger Petstore

Swagger petstore

  • Nothing in the documentation led me to believe that this is designed to be deliberately buggy.
  • But it did seem to have many functional issues when I tried it so in that sense it is worth exploring, but if you are not used to testing APIs it might frustrate you.
  • Because it is swagger based it has a GUI, but you can download the Swagger file and load it into your API Client of choice.
  • Or use the Network tab to view the requests and then replicate them in a REST Client.
  • It is a CRUD interface, and you can seem to make changes on the server.

Automation Exercise Endpoints

This was interesting and a bit weird so I wouldn't recommend it as a First Time API. It felt more like a 'puzzle API' since it wasn't well documented and I had to explore request formats to get it working.

Automation Exercise.com

  • This site has a list of API End Points that you can use to practice testing.
  • An interesting example of non-standard payloads and requests which made interacting with it a bit of a puzzle.
  • Hard to know if it is deliberately buggy or not. But I made notes of lots of inconsistencies. It kept me entertained for an hour or so.
  • Data is saved to the server so you can practice CRUD operations.

Reqres

I found Reqres a little hard to understand from the documentation. It seems as though it has a hard coded set of users /api/users and then a hard coded set of data that it returns from /api/<insert entity name here> e.g. /api/things.

  • reqres
    • Supports JSON only
    • Has hard coded data.
    • Provides a Swagger API interface and documentation this can be useful to get started but doesn't cover the generic endpoints so you'll need to use a REST Client for that.
    • There is also a hard coded set of 12 'things' which will respond to any endpoint e.g. GET https://reqres/in/api/books/1 will return the hardcoded 'thing' with ID 1 (it won't be a 'book' but the API responds as though the /api/books/ end point exists)
    • Simulates DELETE, PUT, POST, PATCH operations.

Compile and run yourself apps

To have the most control over your practice testing session you can download an application and run it locally. All API calls would then be made to http://localhost. You won't experience any issues with SSL, HTTPs, Certificates. There will be no issues with using private data because it will be stored locally.

Getting started with these applications can be a little harder than using the online versions and may require installing Java, Node or Docker.

I've listed a few applications here initially and will expand the instructions to include walkthroughs and setup guides in future updates.

Free to Use API lists

The important thing to remember about list of free to use APIs is that the APIs are not designed for testing. They will either be GET interfaces to retrieve data or you will need to register and create an authentication key.

I've included a few collated lists for completeness if you want to go beyond the practice APIs listed above.

 

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