REST API Testing : From Manual Approach to Automation Techniques

It’s the slowest and the most expensive test because it replicates real user actions in the browser. You can’t write good UI tests without a full understanding of your app’s requirements and end goals. Verify that the HTTP status code returned by API is correct in case of valid parameters , invalid parameters , unauthorized request . Also verify that the API handles the case of server or network failures gracefully, returning suitable HTTP status 5xx code. Performance testing – Verify if the response time of the API calls is too high or varies considerably. Also we can verify if the performance of the API response degrades when called using a large number of clients.

Since APIs help systems to integrate and communicate, it is important that you check each system endpoint where an API call can make impact. HTTP based Restful APIs are connecting the digital space in a way imagined never before. By releasing different APIs for specific functionalities, companies like Twitter, Facebook, LinkedIn and Google have allowed outside world to use and enhance them. This helps these companies reach to a variety of platforms and new markets/users. On the other hand, this allows numerous third-party users to leverage these features for making their own product.

The key is to develop a system that assesses changes needed for current tests and then updates them or even creates new tests. This can substantially reduce the time and effort it takes to be sure that your tests do not fail as a result of unexpected changes and that they don’t ignore new functionalities. This testing is essential and happens in the final steps of the development. It confirms various features and the correct behavior of the product and also efficiency. Parasoft’s API testing platform enables you to proactively manage change by automatically monitoring APIs and services and visually highlighting where updates have occurred.

Testing PUT Request

We can also retrieve values to be used in the future, i.e. we can perform several scripts, depending on your needs. End-to-End testing can be done by the testers either manually using tools like Postman and SOAP UI or automated using HTTPClient or Rest-Assured libraries. First, requested data is sent to the server by the client in order to fetch a response from the server. When a user opens a social media app — such as Twitter or Instagram — they are asked to log in. This can be done independently — through the app itself — or through Google or Facebook.

How is REST API testing performed

Some Rest API Testing requirements are required to ensure that everything is configured correctly. In addition to the above questions, it is important to have a good understanding of the meaning of passing and failing the test. The engineering requirements and sessions that trigger the attack and send it to the system, preferably inside and outside the network. As APIs increasingly link our most intimate and sensitive data, their value continues to grow. Hundreds of expensive endpoints are very attractive to hackers.

How I test an API of a microservice – (5 min read)

GET– The GET method is used to extract information from the given server using a given URI. While using GET request, it should only extract data and should have no other effect on the data. POST − This method is used for creating new entities, as well as to send data to server, such as customer information, file upload, etc. through HTML forms. A browser-based platform to optimize the process can also be used to identify and eliminate bottlenecks. Get details and guidance on how to choose the right API testing solution for your organization. Here are two examples of situations in which you would want to perform API tests.

They are a chance to learn more about us, our products, and how to level up your skills with our tools. Review the specific requirements needed to run our applications. Learn how different organizationshave benefited from using Inflectra products to manage their software testing and application develooment. We collaborate with a wide range of teams to bring our customers a range of services , complimentary technologies, and specialized tools for specific industries. The ability to see the request and response bodies in a variety of formats, including JSON and XML. The best tools offer automated formatters to make the data easier to enter and view.

It is a software architecture style that relies on a stateless communications protocol, most commonly, HTTP. REST structures data in XML, YAML, or any other format that is machine-readable, but usually JSON is most widely used. REST follows the object-oriented programming paradigm of noun-verb. 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 documentation testing — also called discovery testing, the API documentation easily guides the user.

REST API Testing: How to Do it Right

For automated QAs with extensive knowledge of JavaScript, Postman has a JS testing library. Another type of web API is SOAP API – a legacy web communication protocol that is still in use. SOAP isn’t limited to HTTP/HTTPS protocol but supports many others including TCP, SMTP, and FTP, but it works with XML format only.

  • During this test, testers discover whether users with little API expertise can gain access to the full API including information about processes, functions, and resources.
  • If they are not validated properly, issues such as wrong string/data types and parameter data outside the predefined value range can come up.
  • There is no standard for the description format of REST services.
  • The purpose of rest api testing is to record the response of rest api by sending various HTTP/S requests to check if rest api is working fine or not.
  • It’s a free open-source tool with custom scripting functionalities that require advanced programming skills.
  • You can also use these tools to interact with your REST API during the development phase for quick tests.

Well, put simply, and API is a set of rules which help programs to communicate with each other. The developers create APIs on the servers, which permit clients to talk to them. Whether a typical consumer knows it or not, APIs are utilized in the services and applications they user every day.

How to Get Started Testing APIs

It caches test results and data providing their offline replay and analysis. To ensure the API can handle the expected or higher load, QA engineers validate its functionality and performance by artificially creating or simulating API calls. One of the functional testing types is Positive / Negative testing. Negative testing checks how an API responds to every possible kind of wrong input, while positive testing verifies the correct functioning of the API when the input conforms to the norm. If positive test cases fail, it’s a bad sign, as it means the application can’t perform even under ideal conditions.

How is REST API testing performed

But the business logic layer must also communicate with other applications as well as human users. API testing is the process of sending requests to an API and monitoring the responses to ensure its behaving as expected. API testing is designed to assess the functionality, reliability, performance, and security of an API, and is therefore an essential part of the API development lifecycle. Another example is travel booking systems, such as Expedia or Kayak. Users expect all the cheapest flight options for specific dates to be available and displayed to them upon request when using a travel booking system.


Typically, REST Web Services expose their operations as a series of unique “resources” which correspond to a specific URL. Each of the standard HTTP methods then map into the four basic CRUD operations on each resource. There should be a way to see the raw SOAP XML structure for both the sent request and the retrieved response. Ideally there should be a way to see the XML data nicely formatted so that it’s easier to understand the interactions. However, this is called “breaking compatibility” and means that all clients of the API will need to be updated. Sometimes this option is necessary but it should be avoided if possible.

GRPC is a Google-developed open-source data interchange mechanism that uses the HTTP/2 protocol. GRPC APIs exchange data using the Protocol Buffers binary format , which imposes standards that developers must follow when creating or using gRPC web APIs. While REST APIs are mainly useful for microservice architectures and third-party apps, gRPC is often applied in IoT systems, browserless mobile apps and applications with multiplexed streams. • Expected users and frequency of use of specific application features. • Help the development team to identify the performance problems with the growth of the user base . Simulate access to the behavior of the dependent resource, such as a database, a mobile app, a third-party service, or a legacy system.

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OWASP ZAP, potentially enhanced with some additional system tests. Testers need to ensure that REST API calls are called in the correct order to prevent errors. In REST APIs this is especially important since they are generally multithreaded. Although stateful REST APIs are theoretically compatible with any protocol or data format, they mostly communicate through HTTP, using JSON, XLT, HTML, XML, or simple text. Out of these data formats, JSON is the most common as it is compatible with most languages.

Next Steps

GUI testing is then reserved for validating typical use cases at the system level, mobile testing, and usability testing. What if you had some automated ways to verify that every bit of your code works as you code? An automated test compares an actual outcome with the expected outcomes. Rest AssuredAPIautomation framework- REST Assured is a Java library for validation of REST web services. It offers a friendly DSL that describes a connection to an HTTP endpoint and expected results. As both large enterprises and startups increasingly rely on APIs to integrate their software, thorough verification of APIs becomes crucial before rolling out the same to client/end users.

Thus, a great potential for volatile and unpredictable traffic exists. It’s wise to use broad performance testing to determine if your API meets expectations when it encounters surging demand or erratic behavior. 4) Use service virtualization for extensive performance testing. Simulate your API’s behavior by developing a test scenario API users can create and test for that doesn’t affect the production product. This also allows development and subsequent testing even if APIs are not yet complete.

The API response can be checked in a Results Tree listener. If an end user can enter this value through a GUI text field, the field validation should either strip the extra characters internally or prompt user to enter a specific format for MSISDN. api testing best practices Reliability tests – Check whether the API can consistently return correct response, or do response failures occur often. Requests, an open-source Python HTTP library, was released under the Apache2 License with the aim of simplifying HTTP requests.

How to Load Test RESTful APIs with JMeter

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Enables runtime error detection, advanced REST and gRPC API scans, and OWASP vulnerability detection. Below are the various response code, one might encounter while API Testing. GET − This method is use to collect information from the server through a URI . This method must only extract information and should not affect data in any way. To validate your results, call an assert method to validate the endpoint response. This article will demonstrate via examples how to resolve the Principles Of Rest Api Test Design error .

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