List of the Top 25 Free API Testing Tools in 2025

Designed for optimal performance and effective resource management, KrakenD is capable of handling an impressive 70,000 requests per second with just a single instance. Its stateless architecture promotes effortless scalability, eliminating the challenges associated with database maintenance or node synchronization. When it comes to features, KrakenD excels as a versatile solution. It supports a variety of protocols and API specifications, providing detailed access control, data transformation, and caching options. An exceptional aspect of its functionality is the Backend For Frontend pattern, which harmonizes multiple API requests into a unified response, thereby enhancing the client experience. On the security side, KrakenD adheres to OWASP standards and is agnostic to data types, facilitating compliance with various regulations. Its user-friendly nature is bolstered by a declarative configuration and seamless integration with third-party tools. Furthermore, with its community-driven open-source edition and clear pricing structure, KrakenD stands out as the preferred API Gateway for enterprises that prioritize both performance and scalability without compromise, making it a vital asset in today's digital landscape.

Simplified Testing Without Code Empower every member of your team, not just developers, to create and manage automated tests effortlessly. Address your testing needs efficiently, achieving comprehensive test coverage in mere days instead of several months. Our tests designed in natural language are highly resilient to changes in the codebase, and our AI swiftly fixes any test failures that may arise. Continuous Testing is essential for Agile and DevOps practices, allowing you to deploy features to production within the same day. Boozang provides various testing methods, including: - A Codeless Record/Replay interface - BDD with Cucumber - API testing capabilities - Model-based testing - Testing for HTML Canvas The following features streamline your testing process: - Debugging directly within your browser console - Screenshots pinpointing where tests fail - Seamless integration with any CI server - Unlimited parallel testing to enhance speed - Comprehensive root-cause analysis reports - Trend reports to monitor failures and performance over time - Integration with test management tools like Xray and Jira, making collaboration easier for your team.

Testim offers a rapid method for developing robust end-to-end test cases, accommodating both codeless and coded options. It empowers users to design stable, codeless tests utilizing advanced AI capabilities. Additionally, you can export your tests into code format, with access to Testim's JavaScript API for seamless integration with your development environment. This functionality enables you to easily debug, adjust, or refactor your tests as needed. To ensure consistency, you can store your tests in a version control system, allowing for execution with each code commit. Each month, millions of users, including notable companies like NetApp, Wix, and JFrog, rely on Testim for their testing needs. For further information, please visit our website to explore all that we offer.

Postman is a collaborative platform tailored for API development, aimed at streamlining the process of creating APIs while promoting teamwork, which leads to the quick production of high-quality APIs. Its various features support every stage of API development, thereby enhancing collaboration and expediting the process of building superior APIs. Users have the ability to rapidly and easily send requests for REST, SOAP, and GraphQL APIs right within Postman, which optimizes their workflow significantly. Moreover, it offers the capability to automate manual testing, integrating these tests into your CI/CD pipeline to prevent potential issues when new code is deployed. The platform also enables effective communication regarding API behavior by allowing users to simulate endpoints and their responses without needing a backend server. Additionally, you can create and publish visually appealing, machine-readable documentation, making your API more user-friendly and accessible. Regular monitoring of performance and response times keeps you updated on the health of your API, allowing for proactive management. Furthermore, Postman encourages a shared environment for both the creation and consumption of APIs, fostering real-time collaboration among team members, which can lead to more innovative solutions. This combination of features not only enhances productivity but also helps teams work more cohesively towards developing robust APIs. Postman’s AI Agent Builder is a comprehensive tool that accelerates the creation, testing, and deployment of AI agents by providing easy integration with APIs and LLMs. It allows users to quickly turn APIs into agent-ready tools, test LLMs’ performance and costs, and compare responses to choose the best model. The no-code platform features a visual canvas that lets developers design and configure agent workflows with ease.

Cerberus Testing streamlines continuous testing with a low-code software solution that scales efficiently. This innovative tool removes the necessity for establishing an internal testing framework for an extended period. It empowers users to swiftly navigate through the entire testing lifecycle, encompassing test repository management, execution, and report generation. Furthermore, the platform fosters collaboration among teams, enabling them to work together from the creation of use cases to the execution of test cases across various browsers and devices. To facilitate large-scale test execution, users can tap into either their own or third-party robotic infrastructures, allowing a stronger focus on delivering business value. The solution also offers numerous integrations, including Bitbucket and Slack, to enhance implementation speed. As an open-source initiative, it benefits from the contributions of several major digital and retail companies, such as La Redoute, Decathlon, Adeo, and Norauto, ensuring its continuous improvement and relevance in the industry. This collaborative effort not only enriches the software's features but also builds a robust community around it.

Tuskr is an intuitive and robust test management software that simplifies the testing process. This tool enables users to handle test cases, execute test runs, and enhance their testing efficiency. Additionally, it allows seamless integration with existing bug tracking and time management applications. A complimentary 30-day trial featuring sample data is available for those looking to evaluate its capabilities, alongside a generous free plan for users who want to continue using it. With such offerings, Tuskr makes testing management accessible to teams of all sizes.

API Tester is a versatile mobile application available for both iOS and Android platforms that facilitates the testing and utilization of APIs. This entirely free tool boasts a streamlined design while offering extensive functionality, enabling users to tackle complex tasks efficiently on smaller screens. - It supports testing for various API types including REST, GraphQL, WebSocket, SOAP, JSON RPC, XML, HTTP, and HTTPS. - Users can execute all HTTP request methods such as GET, POST, PUT, PATCH, DELETE, and HEAD. - The app allows API calls with diverse request data encodings and transfer methods, including query parameters, FormData, and raw data; advanced features permit users to bypass TLS, turn off redirects, and modify timeout settings. - Requests or collections can be imported effortlessly via cURL, links, or files from devices, with compatibility for Swagger, OpenAPI, Postman, and YAML collections. - Sharing requests is made easy with deep links and cURL commands for quick distribution. - It includes a robust GraphQL editor that provides a comprehensive experience featuring a body editor for Queries, Mutations, Subscriptions, and syntax highlighting, as well as a variables editor and documentation access. - Additionally, a WebSocket testing tool is integrated to manage connections and message exchanges through WS or WSS protocols. This means you can seamlessly engage with the APIs you need while on the go, leaving your laptop behind and enhancing your productivity wherever you are!

Leverage the capabilities of Telerik Fiddler HTTP(S) proxy to capture all web traffic flowing between your computer and external websites, which enables you to examine that traffic, establish breakpoints, and adjust both requests and responses as needed. Fiddler Everywhere acts as a flexible web debugging proxy that is compatible with macOS, Windows, and Linux operating systems. It allows for the capturing, inspection, and monitoring of all HTTP(S) communications, making it easier to mock requests and address network issues. This tool can be utilized with any browser or application, providing the ability to debug traffic on macOS, Windows, Linux, and mobile devices running either iOS or Android. It ensures the proper exchange of essential cookies, headers, and caching settings between the client and server. Supporting a variety of frameworks including .NET, Java, and Ruby, Fiddler Everywhere equips you with the tools to efficiently mock or modify requests and responses on any website. This user-friendly approach enables testing of website functionality without necessitating any code changes. With Fiddler Everywhere, you can comprehensively log and analyze all HTTP/S traffic between your machine and the broader internet, thereby enhancing your debugging efficiency and allowing for more in-depth inspection of network interactions. Ultimately, this tool streamlines the process of identifying and resolving issues that might affect your web applications.

Tyk is a prominent Open Source API Gateway and Management Platform, recognized for its leadership in the realm of Open Source solutions. It encompasses a range of components, including an API gateway, an analytics portal, a dashboard, and a dedicated developer portal. With support for protocols such as REST, GraphQL, TCP, and gRPC, Tyk empowers numerous forward-thinking organizations, processing billions of transactions seamlessly. Additionally, Tyk offers flexible deployment options, allowing users to choose between self-managed on-premises installations, hybrid setups, or a fully SaaS solution to best meet their needs. This versatility makes Tyk an appealing choice for diverse operational environments.

ZAPTEST stands out as a premier tool for both Free and Enterprise software test automation and Robotic Process Automation (RPA), leveraging advanced Computer Vision technology to facilitate seamless automation across various digital interfaces for both UI and API. Coupled with our unique 1SCRIPT methodology, ZAPTEST enables smooth automation, allows for parallel execution, and offers unlimited licenses, all of which contribute to a testing suite capable of delivering returns as high as 10X. The platform is versatile enough to automate any task achievable through any digital interface, whether it be a live application or a mockup. By choosing to collaborate with ZAPTEST, partners gain access to unmatched benefits that significantly enhance the software testing landscape and RPA methodologies. Our collaboration fosters innovation, allowing businesses to adopt cutting-edge automation solutions that elevate their efficiency and effectiveness. Moreover, ZAPTEST equips organizations with a cohesive automation platform designed to optimize both software testing and operational workflows, ensuring a streamlined approach to business processes. With our unlimited licensing model, scaling operations is not only simple but also enables businesses to evolve into agile and efficient entities in a competitive market.

Xano provides a comprehensive, managed infrastructure designed to support your backend needs with scalability. It allows you to rapidly establish the necessary business logic without needing to write any code, or alternatively, you can utilize our pre-designed templates for a swift launch that maintains both security and scalability. Creating custom API endpoints only requires a single line of code, streamlining the development process. With our ready-made CRUD functions, Marketplace extensions, and templates, you can significantly reduce your time to market. Your API comes prepped for immediate use, enabling you to connect it to any frontend while you focus on refining your business logic. Additionally, Swagger automatically generates documentation for seamless frontend integration. Xano incorporates PostgreSQL, offering the advantages of a relational database along with the capabilities required for big data, akin to a NoSQL solution. Enhancing your backend is straightforward, as you can implement new features with just a few clicks, or leverage existing templates and extensions to expedite your project. This flexibility ensures that developers can adapt quickly to changing requirements while maximizing efficiency.

Ambassador Edge Stack serves as a Kubernetes-native API Gateway that delivers ease of use, robust security, and the capability to scale for extensive Kubernetes environments globally. It simplifies the process of securing microservices by offering a comprehensive suite of security features, which encompass automatic TLS, authentication, and rate limiting, along with optional WAF integration. Additionally, it facilitates fine-grained access control, allowing for precise management of user permissions. This API Gateway functions as an ingress controller based on Kubernetes, and it accommodates an extensive array of protocols, such as gRPC, gRPC Web, and TLS termination, while also providing traffic management controls that help maintain resource availability and optimize performance. Overall, Ambassador Edge Stack is designed to meet the complex needs of modern cloud-native applications.

Alithya GoTest serves as an intuitive and efficient test hub that promotes teamwork and quick adoption, guaranteeing the dependability of digital solutions for businesses that demand uncompromising quality. Our user-friendly interface facilitates collaboration, execution, and resolution of tests while enabling communication across all team levels, ensuring that both test plans and results include the necessary details for effective analysis. Platform-agnostic in nature, Alithya GoTest enables seamless testing of desktop, web, and mobile applications, eliminating the need for extensive time and resources typically spent on building, maintaining, and integrating testing platforms into development workflows, thus empowering development teams to concentrate on adding value and enhancing quality. In contrast to traditional testing solutions, Alithya GoTest uniquely offers comprehensive end-to-end software testing through continuous testing within a DevOps framework. You can reach out to our exceptional bilingual support team or utilize our consulting, coaching, or online training resources to quickly familiarize yourself with the platform. Additionally, take advantage of our expanding catalog of pre-designed test suites tailored for major ERP platforms, such as Oracle Fusion Cloud, ensuring that software updates do not disrupt your existing solutions, thus enhancing overall operational resilience.

Apidog provides an all-encompassing array of tools aimed at optimizing the complete API lifecycle, allowing research and development teams to implement best practices centered around API design. Featuring a powerful visual editor, the platform enables users to efficiently design and troubleshoot their APIs. It improves user experience with support for JSON Schema, which makes describing and debugging APIs more straightforward. Apidog automates key components of the API lifecycle, such as generating tests from API specifications, performing visual assertions, validating responses, and integrating seamlessly with continuous integration and continuous deployment (CI/CD) processes. Moreover, it supports the creation of visually appealing API documentation that can be either shared securely among teams or published on a custom domain. With its local and cloud-based mock engine, Apidog generates realistic mock data that corresponds to field names and specifications, eliminating the necessity for writing scripts. The suite of high-quality tools allows your team to collaborate effectively while reducing repetitive tasks. You can easily describe your API during testing and generate JSON or XML schemas with a single click. Additionally, creating test cases from APIs, adding assertions visually, and developing complex test scenarios that include branches and iterations becomes a straightforward task. By utilizing Apidog, teams can significantly boost their productivity and enhance collaboration throughout the entire development lifecycle, leading to more innovative solutions and improved project outcomes.

HttpMaster is a specialized tool designed for debugging and testing HTTP requests, particularly for web API applications and RESTful web services. Key features include the ability to create HttpMaster projects that encapsulate the full definition of request items. It offers a wide range of HTTP properties such as headers and URL encoding to ensure thorough testing. Users can leverage dynamic parameters to mimic different input scenarios or establish global API values for consistency. The tool also allows for response data validation using logical expressions, which enhances the accuracy of testing outcomes. Additionally, request chaining enables users to carry over data from one request to the next, facilitating more complex testing scenarios. HttpMaster supports extensive data upload options, including formats like 'multipart/form-data', which is crucial for testing file uploads. Furthermore, it includes a request data builder that allows users to customize the request body with optional parameters, enhancing flexibility. Users can monitor the execution of request items in detail and can organize requests into execution groups for batch processing. The tool also features a comprehensive review and management system for execution data, making it easier to analyze results. Ad-hoc execution is simplified with a basic request tool, and a command line interface is provided for automation purposes. Finally, HttpMaster supports generating PDF reports and executing cURL commands, making it a versatile choice for developers and testers alike.

SyncTree aims to serve as a comprehensive "Super Connecting Platform" designed to seamlessly link any desired services. By incorporating SyncTree STUDIO, a tool that enables users to construct backend business logic through block coding, alongside Block Store, which functions as a marketplace for trading pre-designed backend function blocks similar to an App Store, users can effectively harness data and interconnect services, paving the way for boundless service growth. This innovative approach allows for enhanced flexibility and creativity in service integration.

You have the option to utilize your preferred debugging software to address issues with your Kubernetes services on a local level. Telepresence, an open-source solution, facilitates the execution of a single service locally while maintaining a connection to a remote Kubernetes cluster. Originally created by Ambassador Labs, known for their open-source development tools like Ambassador and Forge, Telepresence encourages community participation through issue submissions, pull requests, and bug reporting. Engaging in our vibrant Slack community is a great way to ask questions or explore available paid support options. The development of Telepresence is ongoing, and by registering, you can stay informed about updates and announcements. This tool enables you to debug locally without the delays associated with building, pushing, or deploying containers. Additionally, it allows users to leverage their preferred local tools such as debuggers and integrated development environments (IDEs), while also supporting the execution of large-scale applications that may not be feasible to run locally. Furthermore, the ability to connect a local environment to a remote cluster significantly enhances the debugging process and overall development workflow.

Introducing Treblle: a dynamic Software Development Kit (SDK) specifically designed to accelerate the development of REST-based APIs. This innovative toolkit provides deep insights into the complex metadata associated with each API request, along with the ability to monitor API traffic in real time. Leverage the strength of powerful analytics while enjoying a complete suite of API governance features. Experience the advantages of automated API documentation, which significantly enhances the efficiency of your projects. Treblle goes beyond the conventional by offering automated security audits for each request, allowing you to refine your workflows effectively. With support for over 18 languages and frameworks, you can ensure smooth integration across your organization while strengthening security measures. Empower your teams to create, deploy, and maintain APIs with remarkable speed, ultimately transforming how your organization approaches API development and management. Additionally, Treblle fosters a collaborative environment where developers can easily share insights and best practices, further enhancing overall productivity.

Experience a cohesive testing journey that encompasses diverse test categories. With our platform, you can apply the same testing scripts whether you're evaluating a web application across a variety of browsers, operating systems, and devices, verifying your APIs' functionality, or performing comprehensive load testing. Our enterprise-ready SaaS solution, provided by Testable and hosted in the cloud, allows you to run tests either in the cloud environment or on-premises using your favorite open-source tools, all while we take care of the test execution, offer real-time reporting, conduct in-depth analysis, and ensure secure cloud storage. Moreover, you can opt to deploy our testing platform on your own infrastructure, safely shielded behind your firewall. With advanced, scalable, and adaptable packaging options—including a user-friendly one-click Kubernetes Helm package—you can conduct functional tests across multiple browsers, operating systems, and devices simultaneously. In addition, you will receive a real-time report featuring live interactive sessions, videos for every virtual user, screenshots, assertions, performance metrics, trend analysis, and a plethora of other insights aimed at refining your testing approach. This all-encompassing strategy guarantees that you possess all the essential tools to elevate your testing initiatives efficiently, ultimately leading to improved software quality.

Monitoring and testing your web services has reached an unprecedented level of simplicity. Assertible provides automated quality assurance tools that safeguard the dependability of your critical infrastructure by thoroughly checking and observing web services across different deployments and environments. Acting as a reliable first line of defense against potential web service breakdowns, Assertible offers clear and effective assertions tailored for your APIs and websites. By reducing the incidence of false positives in automated quality assurance tests, you can be confident in the well-being of your APIs. While it may appear challenging to keep your tests up to date, Assertible simplifies this task by enabling automatic synchronization of your API tests with the latest updates to your specifications. As you adjust responses, parameters, headers, and other components, refreshing your Assertible API tests becomes an effortless endeavor that only requires a single click to sync. Moreover, Assertible integrates smoothly with your existing tools, allowing for functionalities such as executing your web application tests when code is pushed to GitHub or sending notifications to Slack in the event of any failures, thus enhancing your workflow. Consequently, by utilizing these powerful features, development teams can boost their efficiency while ensuring they uphold high-quality standards in their work. The ease of integration and synchronization offered by Assertible encourages teams to adopt a proactive approach to maintaining the health of their web services.

Develop, troubleshoot, and assess APIs with a personal touch instead of an automated one. Finally, a workflow that you'll truly value. Presenting the Collaborative API Design Tool, a platform designed for crafting, validating, and managing OpenAPI specifications. This desktop client supports interactions with both REST and GraphQL, allowing you to effortlessly send requests and review responses. You can easily generate and organize your requests, configure environment variables, handle authentication, create code snippets, and much more. Delve into the details of responses—analyze the complete request timeline, encompassing status codes, body content, headers, cookies, and additional insights. Structure your project with workspaces, folders, and environments while utilizing a user-friendly drag-and-drop interface for requests, accompanied by simple data import and export functionalities. Within a unified collaborative API design editor, you can create, edit, lint, troubleshoot, preview, and oversee your OpenAPI specifications. Moreover, generate configurations for well-known API gateways like the Kong API Gateway and Kong for Kubernetes. Seamlessly synchronize your API designs with version control platforms such as GitHub or GitLab, and deploy straight to API gateways like Kong with a single click, greatly enhancing your development workflow. This tool not only boosts efficiency but also encourages teamwork among members in designing effective APIs, ultimately leading to a more innovative development environment.

Assessing and validating REST services in Java often presents more difficulties than with dynamic languages such as Ruby and Groovy. Nonetheless, REST Assured offers a user-friendly experience similar to those languages, which simplifies the process for developers working within the Java environment. By utilizing REST Assured, Java developers can effectively optimize their testing workflows, resulting in a notable boost in productivity. This tool not only mitigates complexity but also allows for a more efficient approach to service verification.

Loader.io provides a free load testing tool aimed at assessing how well your web applications and APIs perform by mimicking numerous concurrent connections. Registration for testing can be done effortlessly via the web interface or API. Throughout the testing phase, we will create connections to your application, enabling you to monitor the process live. Once the test concludes, you have the option to easily share the results with your team for in-depth analysis and conversation. This service is essential for verifying that your application can manage heavy traffic efficiently. Additionally, utilizing this tool can help you identify potential bottlenecks before they become a significant issue.

RapidAPI Testing provides a well-rounded solution for both functional API testing and monitoring, featuring an intuitive interface that accommodates all API types and integrates smoothly with the RapidAPI Marketplace and Enterprise Hub. This tool enables users and organizations to validate the reliability of their APIs through advanced functional tests crafted for comprehensive assessment. Additionally, it facilitates centralized monitoring of API tests from various geographical locations, boosting overall productivity by integrating with CI/CD pipelines and promoting teamwork among different departments. Moreover, RapidAPI Testing aids users in developing customized functional test flows that guarantee thorough validation of REST, SOAP, and GraphQL APIs. The platform's user-friendly interface offers three unique methods for creating tests, allowing both developers and non-developers to easily produce visual, automated, or code-oriented tests tailored to their specific requirements. In summary, RapidAPI Testing simplifies the API testing workflow, ensuring that all users can effectively verify their APIs' functionality while fostering innovation and collaboration in the process. This makes the tool an invaluable asset for teams striving for excellence in their API management practices.

Test Mace is a modern and versatile cross-platform tool specifically designed for engaging with APIs and automating tests related to them. It empowers users to create requests and scenarios while offering features like variable management, authentication options, an autocomplete function, and syntax highlighting for ease of use. The interface is intuitive, making it easier to develop complex testing scenarios. With just a single click, users can run extensive regression tests, and the results from those tests can be conveniently saved in variables accessible from multiple nodes. Authorization tokens, response headers, and selected parts of response bodies can also be stored, which significantly boosts testing efficiency. Scenarios can be executed in various environmental contexts, facilitating effective management across development, staging, and production environments. Moreover, the tool includes built-in authentication methods that support the most common authentication types, simplifying the setup process for users. A key feature is the quick share functionality, which allows users to effortlessly share requests with team members by simply clicking a button to copy the URL of a specific node, thus fostering easy distribution among colleagues. This streamlined collaboration is vital for successful teamwork, ultimately enhancing productivity throughout the API testing process. Test Mace not only simplifies individual tasks but also cultivates a more cohesive working environment among teams.