What is API Testing?
API testing is a type of software testing that analyzes an application program interface (API) to ensure it meets expectations in terms of functionality, reliability, performance, and security. Since APIs play a major role in our digital lives, API testing ensures that the application is running in an efficient and seamless manner for the end user. Here is our list of 10 API Testing Tools (REST & SOAP Web Services). But first, we’ll discuss important features to consider when choosing an API testing tool.
Important Features to Consider When Choosing an API Testing Tool
In order to leverage the power of an API testing tool, it’s important to choose the best tool or set of tools that will fulfill your organization's or project's needs. Here are some criteria that you should consider when choosing an API testing tool:
- Does the tool have an intuitive and easy to use UI?
- Do you have the ability to run tests without scripting?
- Is the testing data-driven?
- Does the tool support the API/Web service types that your AUT (Application Under Test) is using?
- Can features be automated?
The Best API Testing Tools
#1. Rapise
Rapise by Inflectra is a powerful test automation tool that provides built-in support for testing web and desktop apps in multiple browsers, Java, Windows, .NET, Flash, Qt, SWT, Ajax, WPF, Silverlight apps, REST/SOAP web services, & complex apps (MSDynamics, Salesforce, SAP fiori) in one easy to use package. The platform also bolsters scriptless automation, so anyone can get started with automated API testing. If you’re looking to move away from manual testing and need support for various browsers and technologies, Rapise is the API automated testing tool for you. Rapise includes out of the box support for SAP Hana UI5, Dynamics AX, CRM, NAV and 365, Oracle Forms as well as Salesforce Classic and Lightning.
Pricing starts at $2,499.99 per fixed license per user or $299.99 per month per floating license. There is a 30-day free trial.
#2. REST-assured
Rest-Assured is a Java-based library that is used to test RESTful Web Services. Rest-Assured library also provides the ability to validate the HTTP Responses received from the server, including the Status code, Status message, Headers and even the Body of the response. Its highly customizable HTTP Requests allows quick and efficient testing of a wide variety of Request combinations to ensure every scenario is thoroughly tested.
REST-assured is a free open source tool.
#3. SoapUI
SoapUI is an open-source web service testing application for SOAP and REST Web Services. SoapUI also has the ability to test JMS, AMF, as well as make any HTTP(S) and JDBC calls. If you’re looking for a tool that ensures quality at every step of the API delivery lifecycle – from design to deployment – SoapUI is the tool for you. SoapUI’s capabilities includes: API functional testing, API performance testing, API Security, and API Mocking. The easy-to-use platform also includes testing reporting so your team can measure success every step of the way.
Pricing starts at $599 per feature, per year. There is a 30-day free trial.
#4. Katalon Studio
Katalon Studio is an automation testing software tool developed by Katalon, Inc. The platform has the ability to run automated tests for Web interfaces, APIs, and Windows desktop and mobile apps (both iOS and Android). Katalon Studio provides test recording capabilities for quick debugging and uses visually intuitive reporting and analytics to track performance across tests. Katalon Studio supports integrations with a number of tools, including collaboration platforms (Git, Microsoft Teams, and Slack), execution platforms (SauceLabs, BrowserStack, Selenium Grid, and Kobiton), and CI/CD and DevOps such as Jenkins, Bamboo, TeamCity, CircleCI, and Travis CI.
Pricing starts at $76 per license per month. There is a free version.
#5. Postman
Postman is an API client that allows developers to create, share, test and document APIs. Postman has the ability to create different testing environments and organize tests within ‘collections’ for easy record keeping. The collections act as folders where requests are stored and can be structured in any way with the added possibility to export-import them. Because it’s so easy to stay organized, your entire team can collaborate on testing—including your non-technical team members. Postman supports a wide range of API standards, specs, and formats, including REST, SOAP, GraphQL, OpenAPI, RAML, Swagger, JSON, cURL, WADL, and more.
Pricing starts at $12 per user per month. There is a free version that includes all core tooling and collaboration for up to three users.
#6. JMeter
Apache JMeter is pure Java-based open-source software designed to load test functional behavior and measure performance. JMeter gives you the ability to simulate API calls and real-world conditions, and conduct dynamic API testing on virtually any type of system or infrastructure. Simulate virtual users in over 40 geographical zones across the United states, Canada, South America, Europe, and APAC to measure the performance of your applications as perceived by your users. Real-time performance charts provide valuable insights to uncover problems and solve them quickly.
Pricing information is available on request.
#7. Eggplant
Eggplant Functional is used to create and perform API tests. Eggplant Functional can be run from Mac, Windows, or Linux to test any platform, technology, or browser. It has multiple types of testing applications, including mobile testing, cross platform testing, rich internet application testing, and performance testing.
Pricing information is available on request.
#8. Tricentis Tosca
Tricentis is a software testing company that specializes in software testing automation and software quality assurance products for enterprise software. Its codeless approach makes it easy to be used by anybody, regardless of whether or not they have a technical background. Tricentis supports the entire API journey and has one of the most extensive API technology support. If your API testing tool needs to support a variety of integrated systems that go beyond the standard REST and SOAP protocols, Tricentis Tosca is the tool to choose.
Pricing information is available on request.
#9. Karate DSL
Karate DSL is a framework for API automation testing, performance, and load testing. It runs on Java and uses Apache HTTP client to perform HTTP connections. Karate uses its own simple scripting language; Java knowledge is not required and non-programmers can run tests as a result of the easy to understand scripting language. Tests are super-readable since scenario data can be expressed in-line, in human-friendly JSON or XML.
Karate DSL is a free open source tool.
#10. Apigee
Apigee is a platform for developing and managing APIs owned by Google. Developers can easily build and scale API programs with full API life cycle capabilities. Monitor, analyze, and even monetize your applications to charge for the use of your APIs (or pay royalties to developers). With Apigee, you also have complete control over where you host your APIs—on-premises, Google Cloud, or hybrid.
Pricing information is available on request.
API Testing Tools Honorable Mentions:
- Parasoft
- vREST
- Assertible
- API Fortress
- Airborne