Compare the Top Free API Testing Tools as of April 2025

What are Free API Testing Tools?

API testing software is used to test and validate the functionality, performance, security, and reliability of Application Programming Interfaces (APIs). These tools help ensure that APIs perform as expected under various conditions and meet the required business and technical requirements. Features typically include automated testing, request/response validation, load testing, security testing (e.g., for vulnerabilities and authentication), and performance testing. API testing software often supports integration with continuous integration/continuous deployment (CI/CD) pipelines to facilitate automated testing as part of the software development lifecycle. Compare and read user reviews of the best Free API Testing tools currently available using the table below. This list is updated regularly.

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    Postman

    Postman

    Postman

    The collaboration platform for API development. Simplify each step of building an API and streamline collaboration so you can create better APIs—faster. Postman is a collaboration platform for API development. Postman's features simplify each step of building an API and streamline collaboration so you can create better APIs—faster. Quickly and easily send REST, SOAP, and GraphQL requests directly within Postman. Automate manual tests and integrate them into your CI/CD pipeline to ensure that any code changes won't break the API in production. Communicate the expected behavior of an API by simulating endpoints and their responses without having to set up a backend server. Generate and publish beautiful, machine-readable documentation to make your API easier to consume. Stay up-to-date on the health of your API by checking performance and response times at scheduled intervals. Provide a shared context for building and consuming APIs, and collaborate in real-time.
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    Starting Price: $12 per user per month
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    Cerberus Testing

    Cerberus Testing

    Cerberus Testing

    Cerberus Testing is a low-code software testing automation enabling continuous testing at scale. Using the solution you can remove years of implementing an internal testing framework. The product enables you to quickly iterate through your testing lifecycle, from test repository, execution, reporting and analytics. The solution allows the collaboration of the teams from the use-cases definition to the test case execution on the variety of browsers, devices, apps and APIs. You can leverage your own or external robots infrastructure to execute your test at scale, enabling you to focus on your business value. It supports various integrations for speed of implementation such as Jenkins, Bitbucket, Slack, Kafka. It is available and maintained in open-source by various digital and retail players such as La Redoute, Decathlon, Adeo, and Norauto.
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    Starting Price: €0
  • 3
    Fiddler

    Fiddler

    Progress Software

    Capture all HTTP(S) traffic between your computer and the Internet with Telerik Fiddler HTTP(S) proxy. Inspect traffic, set breakpoints, and fiddle with requests & responses. Fiddler Everywhere is a web debugging proxy for macOS, Windows, and Linux. Capture, inspect, monitor all HTTP(S) traffic between your computer and the Internet, mock requests, and diagnose network issues. Fiddler Everywhere can be used for any browser, application, process. Debug traffic from macOS, Windows, or Linux systems and iOS or Android mobile devices. Ensure the proper cookies, headers, and cache directives are transferred between the client and server. Supports any framework, including .NET, Java, Ruby, etc. Mock or modify requests and responses on any website. It’s a quick and easy way to change the request and responses to test websites without changing code. Use Fiddler Everywhere to log all HTTP/S traffic between your computer and the Internet.
    Starting Price: $12 per user per month
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    ZAPTEST

    ZAPTEST

    ZAPTEST Inc.

    ZAPTEST is a leading Free and Enterprise software test automation and RPA tool. Offerings include Computer Vision technology that allows for Cross-Platform digital interface automation for UI, API, Load testing, and RPA in a seamless process. Combine that with our 1SCRIPT methodology, seamless automation, parallel execution, and unlimited licenses– you get an efficient testing suite that generates up to 10X ROI. We promise that if you can perform a procedure via any digital interface (live application or mockup) manually, ZAPTEST can automate this procedure As-Is! With ZAPTEST’s Enterprise Solution subscription program, you receive unlimited licenses across the entire organization. Regardless of whether your automation needs increase, your cost remains fixed. FARM allows ZAPTEST users to manage all of their devices so you can remotely control cross-environments and projects from any location. ZAPTEST uses many practical applications to enhance its software testing software capabilities
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    Ambassador

    Ambassador

    Ambassador Labs

    Ambassador Edge Stack is a Kubernetes-native API Gateway that delivers the scalability, security, and simplicity for some of the world's largest Kubernetes installations. Edge Stack makes securing microservices easy with a comprehensive set of security functionality, including automatic TLS, authentication, rate limiting, WAF integration, and fine-grained access control. The API Gateway contains a modern Kubernetes ingress controller that supports a broad range of protocols including gRPC and gRPC-Web, supports TLS termination, and provides traffic management controls for resource availability. Why use Ambassador Edge Stack API Gateway? - Accelerate Scalability: Manage high traffic volumes and distribute incoming requests across multiple backend services, ensuring reliable application performance. - Enhanced Security: Protect your APIs from unauthorized access and malicious attacks with robust security features. - Improve Productivity & Developer Experience
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    Alithya GoTest
    Alithya GoTest is a collaborative test hub that is easy and quick to master and integrate, ensuring the quality of any professional digital solutions for companies requiring reliability without compromises. Ensure the quality of your application without sacrificing speed or agility with an easy-to-use, GUI test automation tool. Whether using scripts or not, our flexibility is unmatched, letting you create manual, automated or hybrid test suites for every desktop, web, and mobile application with ease including .Net, Java, WPF and Windows 10, modern JavaScript frameworks like React and Angular and iOS or Andoid with 2050+ browser and platform configurations. No need to jailbreak your devices. Alithya GoTest comes with a keyword library of over 1500 keywords, so you can ensure your GUI and API tests are scalable, robust, and easy to maintain. Alithya also offers consulting, coaching and training to ensure the success of your teams.
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    HttpMaster
    HttpMaster is a debugging and testing tool for various HTTP applications with special focus on web APIs and RESTful web services. Key features: - HttpMaster project to store complete definition of HTTP calls in one single place. - Broad set of HTTP properties (HTTP headers, URL encoding, etc.). - Dynamic parameters to simulate variations of input data or create global API values. - Response data validation with logical expressions. - Request chaining to use data from previous request with the next request. - Extensive data upload support, including 'multipart/form-data'. - Request data builder for creating request body with an optional dynamic parameters. - Request item execution with detailed progress monitoring. - Execution groups to create batches of requests. - Comprehensive execution data review and management. - Basic request tool for ad-hoc execution. - Command line interface. - PDF reports. - Support for cURL commands.
    Starting Price: Starting from $69
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    Telepresence

    Telepresence

    Ambassador Labs

    Telepresence streamlines your local development process, enabling immediate feedback. You can launch your local environment on your laptop, equipped with your preferred tools, while Telepresence seamlessly connects them to the microservices and test databases they rely on. It simplifies and expedites collaborative development, debugging, and testing within Kubernetes environments by establishing a seamless connection between your local machine and shared remote Kubernetes clusters. Why Telepresence: Faster feedback loops: Spend less time building, containerizing, and deploying code. Get immediate feedback on code changes by running your service in the cloud from your local machine. Shift testing left: Create a remote-to-local debugging experience. Catch bugs pre-production without the configuration headache of remote debugging. Deliver better, faster user experience: Get new features and applications into the hands of users faster and more frequently.
    Starting Price: Free
  • 9
    Insomnia
    Design, debug, and test APIs like a human, not a robot. Finally, a workflow you'll love. The Collaborative API Design Tool for designing, testing and managing OpenAPI specifications. The Desktop API client for REST and GraphQL. Make requests, inspect responses. Quickly create and group requests, specify environment variables, authentication, generate code snippets, and more. Get all the details on responses. View the whole request timeline, status codes, body, headers, cookies, and more. Create workspaces, folders, environments, drag-and-drop requests, and easily import and export your data. Create, edit, lint, debug, preview, and manage all of your OpenAPI specs in one collaborative API design editor. Generate configuration for common API gateways such as the Kong API Gateway, and Kong for Kubernetes. Sync your API designs with source control such as Github / Gitlab, and deploy directly to API Gateways such as Kong with one click.
    Starting Price: $5 per month
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    REST Assured

    REST Assured

    REST Assured

    Testing and validating REST services in Java is harder than in dynamic languages such as Ruby and Groovy. REST Assured brings the simplicity of using these languages into the Java domain.
    Starting Price: Free
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    TestMace

    TestMace

    TestMace

    Test Mace is a modern powerful crossplatform tool for working with an API and creating automated API tests. Create requests and scenarios using variables, authentication, autocomplete feature and syntax highlighting. Build complex scenarios using our convenient and simple UI interface. Perform full regression testing with just one click. Assign a request result to a variable and get access from other nodes. Save authorization tokens, response headers or parts of a response body. Run your scenarios in different environment contexts. Use this to organize development, stage and production environments. Embedded authentication methods will help you to do authentication if you use one of the most popular types. You can use quick share feature to share your request with colleagues. Just press a button to copy a specific node's url. All that you need now is to send this url to your teammate.
    Starting Price: $4 per month
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    Pynt

    Pynt

    Pynt

    Pynt is an innovative API Security Testing platform exposing verified API threats through simulated attacks. We help hundreds of companies such as Telefonica, Sage, Halodoc, and more, to continuously monitor, classify and attack poorly secured APIs, before hackers do. Pynt's leverages an integrated shift-left approach, and unique hack technology using home-grown attack scenarios, to detect real threats, discover APIs, suggest fixes to verified vulnerabilities, thereby eliminating the API attack surface risk. Thousands of companies rely on Pynt to secure the no. 1 attack surface - APIs, as part of their AppSec strategy.
    Starting Price: $1888/month
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    Sparrow

    Sparrow

    Sparrow

    Sparrow offers a complete set of tools that facilitate the entire API lifecycle, directing R&D teams toward excellence in API design-first development. Use cURL to send API requests, and support methods like GET and POST. It simplifies interacting with APIs, handling headers, data, and authentication easily. A collaborative open source solution for API development, streamlining the creation of exceptional APIs. By collaborations, developers can shift their development practices earlier in the process, leading to higher-quality APIs and faster development. Experience effortless parallel testing across diverse environments so you get the insights on the go. Sparrow offers powerful tools for securing and managing your API data along with self-hosting capabilities, providing users with complete control over their testing environment. Stay updated with Sparrow's latest developments, insights, and resources.
    Starting Price: Free
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    Hoppscotch

    Hoppscotch

    Hoppscotch LTD.

    Hoppscotch makes it easy to create and test your APIs, helping you to ship products faster. Create APIs faster, test them instantly, document and share them automatically. From prototyping to production - develop without switching tabs. Hoppscotch got everything you need to make API development easy. Create workspaces for your teams. Control access to your workspaces. Work together with your team in real-time. Deploy Hoppscotch on your own servers. Organize your requests in collections or folders and share them with your team. Manage your environment variables and use them everywhere. View and manage your request history. Modify headers, authenticate requests, generate random data, and much more. Test your APIs and write assertions for the response. Use Hoppscotch in your native language. We support 30+ languages. Track all the activities in your workspace. Who did what and when. Use your existing SSO provider to login to Hoppscotch. Manage your users, workspaces, and more.
    Starting Price: $19 per user per month
  • 15
    Katalon Studio
    An all-in-one test automation solution Get started in no time, scale up with no limit, for any team, at any level. Katalon Studio Robust test generation on all platforms Productive IDE to generate automated tests easily for all platforms and OSs, regardless of application complexity. Powerful recording utility for effortlessly storing all UI elements to maximize reusability. Codeless experience for beginners. Infinite testing extension for experts. Set Up Projects Built-in project templates Start immediately with ready-made templates, test case libraries, keywords, and object repositories. All kinds of end-to-end testing in one place Uniquely perform web, mobile, API, and desktop testing – all in a single project.
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    BlazeMeter

    BlazeMeter

    BlazeMeter

    BlazeMeter’s open-source based, enterprise ready platform unifies all the functionality you need to shift testing left - and right. Use our intuitive UI to create tests or reuse your existing scripts and run them at scale as part of your continuous testing strategy. Test and generate detailed reporting and see historic trends. Spend more time innovating & less time maintaining your toolchain. Continuous testing is key to delivering with quality, volume, and velocity. But integrating, maintaining, learning and switching between multiple tools wastes valuable time and resources. BlazeMeter makes it easy with a super intuitive platform that does it all. BlazeMeter delivers complete shift left testing, so you can wow the marketplace with innovation. BlazeMeter provides all the components you need for shift left continuous testing. Work with CLIs, APIs, UI, open source tools, and more. Save HUGE time with setup, maintenance, learning, and day to day use.
    Starting Price: $149 per month
  • 17
    Eggplant

    Eggplant

    Keysight Technologies

    At Eggplant we empower organizations to create amazing digital experiences. We help businesses to test, monitor and analyze their end-to-end customer experience and continuously improve their business outcomes. Companies worldwide use Eggplant to surpass competitors, boost productivity, and delight customers. How? By dramatically enhancing the quality, responsiveness, and performance of their software applications across different interfaces, platforms, browsers, and devices - including mobile, IoT, and desktop — in agile, DevOps, and innovative application and data environments. As software release cycles accelerate, manual testing can't keep up. AI automatically discovers user journeys, hunts for bugs and performs image-based UI tests from the user POV. Build better software with fast, broad, accurate AI-powered testing. To keep up with DevOps, continuous testing is key, streamlining development and automating the testing process.
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    KeyRunner

    KeyRunner

    Launchiam

    The Platform to Build, Test & Secure APIs. Transform how you design, test, and manage APIs. Collaborate easily, run tests locally, and protect sensitive data every step of the way. No Signup or Login Get started instantly—no need for lengthy sign-ups or logins. VS Code Extension & Desktop Apps Work where you're comfortable! Our VS Code extension and desktop apps integrate seamlessly with your existing workflow. Local Storage & Execution Keep data secure with local storage and execution, ensuring sensitive information stays on your device. Run Unlimited Collections Test and manage unlimited API collections, enabling effortless scaling for all your projects. Mock Servers Streamline development by creating mock servers for fast testing and API response simulation. Scriptless Testing & Playground Simplify testing with our user-friendly interface—experiment with APIs without writing any code. Our enterprise features take it even further. Contact us!
    Starting Price: $39/month/user
  • 19
    Requestly

    Requestly

    RQ Labs, Inc.

    Requestly API Client offers a range of tools to help you design, manage, and test APIs effectively. With distinct combination of features Requestly acts as a companion to developers and QAs. 1. Design APIs: Requestly simplifies API Design by allowing you to create individual API requests, specify HTTP methods, headers, query parameters, and request bodies. 2. Send API Requests: Sending API Requests is at the core of API testing. Responses can be viewed in detail, including status codes, headers, and payloads. 3. API Collections: Collections allow you to group related API requests for better organization and collaboration. 4. Variables: Requestly simplify API testing and management by allowing you to replace hardcoded values with placeholders - Collection, Environment, and Global Variables. 5. Scripts (Pre & Post): Scripts allow you to add logic or modify requests before they are sent, or process responses and manipulate variables that can be used in subsequent API call.
    Starting Price: $0
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    JMeter

    JMeter

    Apache Software Foundation

    The Apache JMeter™ application is open source software, a 100% pure Java application designed to load test functional behavior and measure performance. It was originally designed for testing Web Applications but has since expanded to other test functions. Apache JMeter may be used to test performance both on static and dynamic resources, Web dynamic applications. It can be used to simulate a heavy load on a server, group of servers, network or object to test its strength or to analyze overall performance under different load types.
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