17 Best API Testing Tools Reviewed For 2024

Invicti is a web application and API security tool that helps organizations identify and fix vulnerabilities in their web assets. It combines automated discovery and security testing to provide a scalable solution for securing web applications and APIs. 

Invicti stands out as a robust API testing tool with its comprehensive feature set designed to address the multifaceted challenges of API security. One of the most notable features is its ability to cover all major API types, including REST, SOAP, and GraphQL, with built-in security checks. This versatility ensures that regardless of the API architecture in use, Invicti can provide thorough security testing. Additionally, Invicti supports a wide range of API definition formats, such as Postman, OpenAPI (Swagger), WADL, and WSDL, which simplifies the process of importing and testing APIs.

Another significant advantage of Invicti is its automated authentication capabilities. The tool supports popular API authentication methods, including basic HTTP authentication, JSON Web Tokens (JWTs), and OAuth2, which are essential for accessing and testing APIs securely. This feature is particularly beneficial in environments that use single sign-on (SSO) or multi-factor authentication (MFA), as it ensures that the scanner can authenticate and test APIs without manual intervention.

Integrations include MuleSoft Anypoint Exchange, Amazon API Gateway, Apigee API hub, Kubernetes, Azure Boards, Bitbucket, Bugzilla, FogBugz, DefectDojo, Freshservice, GitHub, GitLab, Jazz Team Server, and Jira.

Pricing is available upon request.

Testim is touted as the first automation testing tool to use AI and machine learning. It flattens the time used for testing by recording every action you take and can subsequently turn these into tests in a matter of minutes.

Testim allows you to create stable tests quickly, easily, and accelerate product releases. By using its machine learning algorithm, it analyzes your app and knows which actions to perform when changes are made to your codebase. Therefore, Teslim helps QA teams reduce the need and burden of tedious test maintenance.

There are several tools to automate manual testing but if their pace is too slow, with ramping-up authoring posing significant bottlenecks, then it’s time to consider Testim. Testim allows you to create the most resilient end-to-end test with fast iteration that leverages AI-powered automation.

It comes with robust debugging tools that allow testers to troubleshoot quickly and diagnose failed tests.

it gives you operational control to scale and expand testing without sacrificing test quality. Testim integrates with other popular third-party systems such as Trello, TestRail, Github, and Jenkins. It also provides a modern JavaScript API to enable you to debug, refactor, and customize tests. Testim allows you to export test results with CSV into spreadsheets like Excel.

Testim’s Community plan is free. For its paid plans, customized pricing upon request for its Essentials and Professional plans.

Acunetix is a web application and API security scanner designed to automate security testing, identify vulnerabilities, and facilitate efficient patching. Leveraging advanced technologies like DeepScan, it can analyze complex, dynamic websites built with HTML5 and JavaScript. 

Acunetix stands out with its ability to automatically discover and test APIs without disrupting development workflows. This is achieved through its zero-configuration setup, API management system integration, and network API discovery capabilities. It can detect over 12,000 vulnerabilities, including those listed in the OWASP Top 10 and API Top 10, and provides actionable scan results.

Additionally, Acunetix supports various formats for importing API definitions, such as WADL, Swagger, HTTP Archive (HAR) files, Postman files, and more, making it versatile in handling different API structures. Its ability to integrate with development processes and scan hard-to-reach places further enhances its utility.

Integrations include Azure Boards, BitBucket, Bugzilla, DefectDojo, FogBugz, Freshservice, GitHub, GitLab Issues, Invicti Standard, Jazz Team Server, Jira, and Kafka.

Pricing is available upon request.

Katalon Studio equips DevOps and testing teams with several features to ensure they have a robust strategy to produce well-tested applications.

It is immensely flexible, allowing you to run tests on all platforms, whether desktop, web, or mobile. It can be used on various OSs like Linux, macOS, and Microsoft Windows. Katalon also permits you to run automated tests on UI elements such as pop-ups, iFrames, overlays, and so on.

One of Katalon Studio’s selling points is that it allows you to create and reuse automated scripts without going through the arduous process of writing code. While this codeless experience is a boon for beginners, it also provides sophisticated extensions and plugins for experts.

Moreover, Katalon gives you out-of-the-box, ready-made seamless integration with DevOps pipelines and CI testing tools. These factors help to drastically reduce the time necessary to create automated scripts.

It also provides several ways to customize and enhance your test procedure to fit your application’s context. These include keyword-driven testing, page object model testing, data-driven testing, and TDD/BDD Testing.

It provides support for the command line and other execution environments. It also supports Groovy, a language that is Java domain syntax compatible.

Katalon Studios comes with a free version but it doesn’t provide support for API monitoring in any of its products. Moreover, its paid plans are prohibitively priced, with Runtime Engine and Studio Enterprise costing $1,499 USD per license/year and $1,899 USD per license/year respectively.

Sauce Labs is a comprehensive continuous testing cloud for web and mobile applications that allows you to complete both manual and automated testing through a variety of testing channels. The tool provides a real device cloud so you can test across multiple devices. Sauce Labs also offers enterprise security and a proprietary data center.

Sauce Labs offers a variety of automated and manual testing methods, ensuring full test coverage of your applications. The tool provides a cross browser testing feature, which allows you to test end-to-end on various browsers. Sauce Labs also offers the ability to complete automated mobile testing so you can write tests for various devices to ensure your application runs smoothly.

Sauce Labs offers integrations with platforms such as Github, Jenkins and Bamboo, as well as chat applications such as Slack.

The cost of Sauce Labs starts at $39/month for the Live Testing package. The tool also offers a 28-day free trial.

Smartbear is a simple, yet scalable GUI test automation tool that focuses on desktop, web, and mobile testing. These modules allow you to recreate repeatable tests easily across various platforms, environments, and multiple devices.

Smartbear’s TestComplete feature offers automated UI Testing works across a diverse range of desktop applications, whether they’re built on Windows, or designed with WPF, Java, .Net, or other software languages. It makes continuous testing a breeze by enhancing your ability to run automated tests with test scripts, along with providing record and replay capabilities.

Smartbear’s Cross Browser Testing provides an all-in-one web testing platform for cross-browser compatibility. So, when it comes to web applications, Smartbear allows you to design reusable tests and run parallel execution tests for several platform browser configurations like chrome, including JavaScript frameworks like Angular and React.

Its ReadyAPI solution allows test engineers to accelerate API quality through web services like GraphQL, RESTful, and SOAP.

To add to its strong suite of test products, Smartbear acquired the open-source Cucumber, thereby merging the latter’s leadership in a behavior-driven development (BDD), especially among agile teams, with its expertise in test automation.

Smartbear’s TestComplete and ReadyAPI modules are expensive.

TestComplete Base offers Desktop, Mobile, and Web options; and it allows users to mix and match these according to their needs and affordability. Choosing the Desktop option alone starts at $5,438 USD. Mobile alone costs $6,158 USD, while the Web option by itself starts at $5,438 USD.

Hoppscotch is a free, open-source tool and API request builder. Hoppscotch provides REST API testing via a GUI API client to make HTTP requests and validate API request responses.

Incidentally, it was built as an alternative to Postman. And compared to other API frameworks, Hoppscotch has a more minimalistic, less distracting interface. Hence, Hoppscotch enables you to write test scripts with minimal distraction so requests are created faster.

For instance, Hoppscotch has a feature called Collections, which allows testers to group and save all the HTTP requests belonging to a single API endpoint together in a logical, organized manner.

Hoppscotch is an asset to API development environments because it allows developers to create HTTP requests in a logical, step-by-step manner. Especially when the API contains request objects with many layers of nested arrays and HTML objects.

Along with pre-request scripts, DevOp teams save precious time on their API development efforts. In addition to the REST services it provides, Hoppscoth also incorporates GraphQL to enable developers to retrieve descriptive data queries along with their API tests.

Therefore, Hoppscotch benefits resource-driven apps by ensuring the API is reliable and highly secure.

Hoppscotch is free but it accepts donations through PayPal and Patreon.

Subject7 makes becoming an automation expert accessible to anyone through its codeless automation. Thereby, leveling the playing field when it comes to API testing.

It is an exceptional automation tool for both technical and non-technical users in addition to reducing maintenance for QA engineers and testers. You can create easily create robust test flows with widget definitions, AJAX calls, and configuration templates across a library of over 100 hundred platforms, android, and iOS devices.

Whether it’s web or native app testing, Subject7 simplifies the process by enabling test authoring and running of sophisticated API automation tests a breeze. It incorporates a wide range of end-to-end test capabilities that encompass desktop, web applications, web services, mobile, security, load testing, and much more.

Subject7 is capable of delivering robust testing capabilities that scale adequately while providing enterprise-grade security, whether it’s on-premises or in the cloud.

The adaptability of Subject7 lies in its ability to provide GUI interfaces to interact with a wide range of automated commands, at a minimum, eliminating the need to write java codes. In addition, it provides several in-built commands to perform interactions for web and desktop applications.

It uses both open APIs and native to seamlessly facilitate integration with existing Agile tooling and DevOps ecosystems.

Unfortunately, Subject7 doesn’t provide any free version or free trials for users to test out its features before deciding to make a purchase. Its Professional plan is reasonably priced, although it requires an annual subscription of $250 USD per user/month. Both its Enterprise and Private Cloud plans provide customized pricing upon request.

Postman’s abundant resources make it easy to build, test, and debug APIs together. It allows QA and DevOp teams to stay committed to favorable short release cycles in the spirit of Agile methodology and continuous testing/integration.

Postman provides templates for testers to easily create test suites by reducing the amount of time spent on coding test scripts. Its schema editor makes it possible to work with files of various sizes and formats.

Equipped with an API client that automatically detects the contents of an HTTP response body – from its format, language, and links, Postman provides a streamed and effective environment to work and accelerate API test and development.

In addition to supporting all HTTP methods, it is also possible to define complex API requests for Websockets, GraphQL, OpenAPI, and SOAP formats.

Although Postman’s vast structure can be a challenge to implement for beginners, it more than makes up for this in several ways. It saves work progress by automatically storing all your API calls in your cloud-based system. Hence, you can easily reuse them to quickly create a prototype API workflow.

In addition to all these benefits, Postman is incredibly affordable. It comes with a free version that allows you to do run-of-the-mill stuff like designing and testing APIs. Postman’s other pricing tiers are Basic, Professional, and Enterprise. These are priced at $12, $29, and $99 respectively; all are charged in USD per user/month but billed annually. However, the prices are higher when billed monthly.

Apache JMeter is a desktop application that allows you to measure test performance of applications across browsers and mobile OSs. The tool focuses on loading testing and provides an intuitive user interface. Apache JMeter is also capable of carrying out other testing types such as functional testing.

Apache JMeter can turn on/off variables depending on your target testing environment, which allows you to configure your test cases easily. The tool allows you to identify the issues in your performance by scaling your tests and rerunning existing scripts.

Apache JMeter also allows you to run stress tests so you are able to find breaking points in your systems, ensuring their reliability.

Apache JMeter is fully open source and free to use.