We need this as when we run tests against our live API, each test assumes a constant state of data. When we run a test that deletes a book, then we have a test that assumes that the book is present, and our tests can fail. We can use this endpoint to ensure we have a predictable state, which is always a critical goal of writing tests. The first few lines set up the basic web host, and then we are initializing a set of Book records, which we’ll use to act as the resource for our REST API.

REST API Testing

It will not make sense if the selected tool supports testing RESTful services while your AUT is using SOAP services. In addition, this step also helps you define the verification approach. Is a standard protocol defined by the W3C standards for sending and receiving web service requests and responses. Thanks to low-code, API testing is not something only developers and professional QAs can cope with.

What is JSON?

Version 0.9.6 of Karate DSL includes async capability-based support for WebSocket. It offers easy-to-write tests for those who aren’t into core programming, as well as support for multithreaded parallel execution and configuration staging/switching. In addition, because the tool is built on top of Cucumber-JVM, you can execute test cases like any project developed using Java. Only, instead of Java, you have to write scripts in a language that makes it easier to work with JSON or XML. On top of that, you can often integrate an automated API testing tool with your continuous integration pipeline. This integration is an excellent choice to improve your code’s quality by detecting bugs early on in the software development lifecycle.

So, the key here is to opt for API testing tools after you’ve thoroughly worked with some tools and found out which one works best for you. Apigee offers a free trial to users so that they can check its compatibility with specific requirements. The packages include Evaluation, Standard, Enterprise, and Enterprise Plus. Users can access its features using different editors, such as Swagger. It also enables measuring and testing of API performance. However, for additional features, it costs $12 for each user per month.

Besides, ReadyAPI supports the OpenAPI, Swagger and RAML formats. There are mainly 4 methods involve in REST API automation testing like GET, POST, Delete, and PUT. POST– A POST request is used to create a new entity. It can also be used to send data https://globalcloudteam.com/ to the server, for example, customer information, file upload, etc. using HTML forms. We could have just referenced the API project and the Book record directly in Visual Studio, but remember we are testing the API from a client perspective.

It is painful if errors occur because you will have to debug the data flow generated by API in a sequence. There are some cases in which you need to call a series of API to achieve an end-to-end testing flow. However, these tasks should come after all APIs have been individually tested. An API is essentially the “middle man” of the layers and systems within an application or software. Web Testing Robust solution for end-to-end web automated testing.

Response Assertions in REST API Testing

The trade-offs of course are speed , and not having a predictable state . We could do unit tests by saving the API responses to a JSON file, then mocking HTTP Client to return the mocks. But then we aren’t really testing the API we are using, so let’s stick with integration tests here.

The main difference is the client-side tests only test the behavior that we are interested in for our use cases, whilst the server-side will test all use cases. Representations are when a server sends a response with the resource in a finished format. Our HolidayWebservice web service is the most typical kind, in that a client sends a request to the service and waits.

  • It’s also feature-rich and supports every stage of the REST API lifecycle.
  • Obviously in reality our security approach will be more robust than here, using something like JWT and Identity, but for our testing purposes, this will suffice.
  • Launch the app Advanced REST client , once it is installed successfully.
  • Assuming the Content-Type header is set to application/json, we can safely assume the content itself is in that format and attempt to deserialize it into a model.
  • Sign up for a Free Trial to build visual, interactive experiences.
  • Here, you will find pros and cons of each web service as well as example code.
  • The data formatting schema specifies how REST APIs handle responses and requests.

Before we jump into code, let’s spend a moment understanding why API testing is important. In this article, we are going to cover how and why we should test a REST API with .NET and xUnit. We’ll discuss why this is important, and how to actually test various components of an API response to ensure requirements are being met. Thus far, we’ve only worked with services that return XML; now, we’ll get our first look at what it’s like to work with a service that returns JSON. Request — provides more information about the client to the server.

Checking if the site connection is secure

You can also use the windows power shell with curl, but you have to remove the curl alias. Codeception has two modules that will help you to test various web services. Remember, you are not limited to test only response body. By including Db module you may check if a user has been created after the CreateUser call. You can improve testing scenarios by using REST or SOAP responses in your helper methods. The following tutorial is for REST API automation testing using Postman.

REST API Testing

However, it does not reflect all test scenarios of the API. Knowing the purpose of the API will set a firm foundation for you to well prepare your API testing data for input and output. Is the web standards-based architecture that uses HTTP. Unlike SOAP-based Web services, there is no official standard for RESTful Web APIs. Launched initially as Chrome plugin, Postman has evolved to become a top-tier API testing tool.


Postman is a popular API client that allows developers and teams to test, share, create, collaborate, and document the API development process. The client is ideal to create and save the complex, as well as simple HTTP/s requests along with their responses. Postman can be downloaded as a Chrome extension, or you can visit the official website to download the program. In general, REST testing is sending different requests to a REST API and verifying responses from it. SoapUI supports extensive testing of RESTful web services and their resources, representations, and so on. Automated API testing tools will save you time and increase the functionality, reliability, and security of your application.

REST API Testing

Additionally, it can help to identify potential security vulnerabilities in the API before the software is released. Use Postman’s Collection Runner to run collections of requests in specific sequences, log test results, and pass data between requests—or even pass data files into a run. Collection runs allow you to automate your API testing, and you can schedule runs using monitors. Create test suites that can run again and again—from simpler functional tests to comprehensive, end-to-end tests and full regression testing. Send requests and examine API responses directly within Postman to find fixes quickly. Once the testing process is completed, you can get the result of those tests every day.

Build APIs that work.

This gave them an idea to create what they call API functional testing. A small piece of the total number of automation test types that should be created. This image represents the opposite of the way most non-agile development teams perform automated testing. All the reasons I just listed have given test automation a reputation for being unreliable and not worth the effort to create. Luckily, the type of automation Agile focuses on is Unit testing (and the more reliable API lower-level testing) and less on GUI automation. With Agile development becoming the standard in most organizations, the ways in which we develop software and automate tests have changed dramatically.

REST API: what is it?

These tests are totally different from GUI tests and do not emphasize business logic layer of the system architecture. Automation testing of API needs an app that can interact through an API. With APIs increasingly becoming essential components for software development, it has become vitally critical for developers and programmers to perform API tests.

It’s nothing but a small script wrapper around curl that focuses on testing REST APIs. Just install this little tool and source and you can start testing your REST APIs from the command line. RESTful API defines a set of functions that developers can use to perform requests and receive responses via HTTP protocol, such as GET, POST, PUT and DELETE.

Specify the API output status

REST-assuredREST-assured is an Open Source tool to test REST APIs in Java. The tool is especially loved by Java developers who can test web services easily and fast via it. SwaggerSwagger is an Open Source API development, design, and testing platform for different team sizes. Swagger uses the OpenAPI Specification – the industry standard for designing REST APIs. This is the best course to learn REST APIs for Java developers.

This tool enables loading web servers, websites and web apps by simulating real-world behaviours and testing environments. It offers a user-friendly GUI, is easy to install, provides testing strategies, simulation, and other performance testing features. Media Type –All responses should have the Content-Type header, which tells the consumer what content to expect.

Adding Assertion

The best thing about SoapUI is that you can use this tool to test both SOAP Web Services as well RESTful Web Services or HTTP-based services. It’s also feature-rich and supports every stage of the REST API lifecycle. Through design, testing, and full production, Postman is there for faster, easier API development — without the chaos. If you are not a big fan of command-line tools and rather like a GUI client to test your REST API then Postman is the best tool for you.

REST is very data-driven, compared to SOAP, which is strongly function-driven. You may see people refer to them as RESTful APIs or RESTful web services. api testing best practices They mean the same thing and can be interchangeable. The data formatting schema specifies how REST APIs handle responses and requests.

The tool that is most commonly used for API testing is Testim. Testim is a powerful tool for API testing that makes it easy to create and execute automated tests for your API. Testim also provides a wide range of assertions and verifications that you can use to validate the results of your API tests. Hoppscotch brands itself as a lightweight API testing tool with a minimalistic UI. The tool itself offers a complete set of functionality to make testing easier. Moreover, JMeter 5.4 came out in December 2020 with additional bug fixes and core enhancements.