List of the Top 25 Free API Design Software 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.

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.

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.

Effortlessly manage APIs across both cloud-based and on-premises environments: In addition to utilizing Azure, establish API gateways that work in tandem with APIs deployed across various cloud services and local infrastructures to optimize API traffic flow. It is crucial to uphold security and compliance standards while ensuring a unified management experience and full visibility over all APIs, both internal and external. Speed up your operations through integrated API management: Modern businesses are increasingly adopting API frameworks to drive their growth. Streamline your workflows in hybrid and multi-cloud environments by using a centralized platform to oversee all your APIs effectively. Protect your resources diligently: Exercise the option to selectively grant access to data and services for employees, partners, and clients by implementing measures for authentication, authorization, and usage limitations. This approach not only helps maintain tight control over access but also fosters collaboration and efficient interactions, thereby enhancing overall operational effectiveness. Ultimately, a robust API management strategy can be a key driver of innovation and efficiency within an organization.

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.

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.

BuildShip serves as a user-friendly low-code platform that allows for the visual assembly of backend solutions, making it easy to deploy APIs, set up scheduled tasks, develop AI-driven workflows, and create cloud functions quickly. The platform integrates smoothly with multiple databases, tools, and AI models, enabling users to construct detailed backend logic flows tailored to their needs. Users can choose to work with existing nodes or tap into AI capabilities to develop custom logic nodes that fit their specifications perfectly. By balancing the ease of no-code development with the extensive flexibility offered by low-code, BuildShip delivers a scalable approach to backend development that can adapt to various needs. It caters to an array of powerful applications, such as processing payments and managing subscription services through platforms like Stripe, RevenueCat, and Lemon Squeezy. Moreover, it supports the automation of AI workflows essential for enhancing backend functionalities in AI applications, facilitating the creation of APIs for efficient data manipulation and CRUD operations across different databases. Users can easily transfer form submission data to external applications, integrate AI-driven chatbots with services like OpenAI, Azure, Claude, and Groq, and manage email communications effectively to boost user engagement and lead generation. With BuildShip, the potential for innovation knows no limits, empowering users to explore new ideas and solutions freely. In a landscape where technology evolves rapidly, BuildShip stands out as a versatile tool that adapts to meet the ever-changing demands of developers and businesses alike.

A single platform enables the construction, integration, and exposure of your digital services as managed APIs across cloud, on-premises, and hybrid environments, thereby facilitating your digital transformation strategy. You can seamlessly integrate with your current identity access and key management solutions to enforce industry-standard authorization protocols, including OAuth Connect, OpenID Connect, or JWTs. This platform allows for the creation of APIs utilizing existing services, offers management capabilities for APIs sourced from both third-party providers and internally developed applications, and provides insights into their usage, performance metrics, and decommissioning processes. Furthermore, to enhance support for developers, elevate your services, and encourage broader adoption, you can deliver real-time statistics on API usage and performance, enabling informed decision-making among stakeholders. Such comprehensive functionality makes it an invaluable tool for organizations aiming to stay competitive in a rapidly evolving digital landscape.

With the cutting-edge IBM API Connect, organizations can efficiently secure and oversee every element of their API ecosystem across various cloud infrastructures. This platform enhances both socialization and monetization initiatives, enabling businesses to thrive in the digital landscape. IBM API Connect®, recognized for its comprehensive, user-friendly, and scalable nature, empowers users to develop, securely share, and administer APIs across diverse cloud environments. By doing so, it enables businesses and their clients to drive innovation and develop digital applications effectively. Additionally, IBM API Connect can integrate with other tools as part of an IBM Cloud Pak®, aiding organizations in achieving their application modernization objectives during their cloud transition. Security within IBM API Connect is fortified by the sophisticated IBM® DataPower® Gateway, which features a single, signed, and encrypted gateway, significantly mitigating the risk of cybersecurity threats. With a remarkable 22% market share, it surpasses all competitors, establishing itself as a reliable API solution that safeguards services and data throughout various cloud settings. This comprehensive approach not only enhances security but also empowers companies to innovate and adapt to the rapidly evolving technological landscape.

Directus serves as an Open Data Platform, enabling the management of content across various SQL databases. It boasts a robust API for developers while providing an easy-to-navigate application for users without technical expertise. Built entirely in JavaScript, mainly utilizing Node.js and Vue.js, Directus is both modular and adaptable, allowing for customization to fit unique project requirements. This versatility enables the platform to function effectively as a headless CMS, a database client that promotes information accessibility, or even a standalone web application designed for managing back-office tasks such as CRM, inventory tracking, business intelligence, and project management, thus enhancing overall operational efficiency. With its wide range of applications, Directus empowers organizations to streamline their processes and optimize their digital experiences.

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.

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.

DreamFactory serves as a comprehensive platform for managing REST APIs, enabling the automatic generation of these interfaces. This robust solution can be deployed either in the cloud or on-premises, ensuring it meets enterprise-level standards. By facilitating instant creation of database APIs, it accelerates application development, allowing projects to be completed in weeks rather than months. The platform effectively removes significant delays commonly faced in contemporary IT environments. DreamFactory delivers a fully documented, secure, standardized, and reusable live REST API. It provides integration capabilities with a variety of SQL and NoSQL storage systems as well as SOAP services. The platform generates REST APIs complete with Swagger documentation, user roles, and additional features right out of the box. Each API endpoint benefits from comprehensive security measures, including User Management, Role-Based Access Control, and SSO Authentication, all accompanied by Swagger documentation. Developers can swiftly build mobile, web, and IoT applications using REST-based APIs. Furthermore, DreamFactory includes sample applications for platforms like iOS, Android, and Titanium, making it easier for developers to get started. This extensive support fosters innovation while streamlining the development process.

Gravitee.io stands out as an exceptionally affordable and high-performing Open Source API Platform that empowers organizations to securely publish, analyze, and protect their APIs. With its certified OAuth2 OpenID Connect (OIDC) and Financial-grade API (FAPI) servers, Gravitee.io enables effective identity management. The platform's API management features allow for precise control over who can access your APIs, as well as the timing and manner of that access. Its lightweight design, combined with flexibility and impressive speed, makes it an ideal choice for developers. Gravitee.io also offers comprehensive tools for managing, monitoring, deploying, and securing APIs, complemented by robust governance features such as API reviews and quality assessments. Additionally, the Gravitee.io portal enhances the engagement experience for API consumers, fostering meaningful interactions and ensuring that organizations thrive in the digital landscape. By leveraging Gravitee.io, businesses can significantly elevate their API strategy and achieve superior operational efficiency.

Stoplight serves as a comprehensive platform for API design, development, and documentation. The Stoplight Platform fosters consistency, reusability, quality, and simplicity throughout the API lifecycle. Here’s how the Stoplight Platform can benefit your team: With Stoplight Studio's intuitive visual designer, crafting APIs becomes a straightforward task. The Stoplight Prism tool enables the automatic generation of mock API designs, enhancing your workflow. You can invite both internal and external collaborators to provide feedback and engage in the design process. This leads to the creation of APIs that are not only faster but also more robust. Additionally, by utilizing Stoplight Spectral, you can thoroughly test and uphold style guidelines. Automated documentation for both internal and external APIs ensures a seamless experience for all stakeholders. To efficiently scale API initiatives that are well-governed and collaborative, integrating design-first workflows is essential. This approach not only streamlines the process but also enhances overall productivity and collaboration among teams.

SwaggerHub serves as a versatile platform that merges API design with documentation, intentionally designed for teams to uphold consistency and structure during the API development journey. By utilizing a robust Editor that complies with the latest Swagger (OpenAPI) specifications, your team can boost design efficiency while ensuring quality and a consistent organizational style. This advanced Editor offers smart error feedback along with automatic syntax completion, simplifying the coding experience significantly. It also features Style Validators to ensure that design consistency is maintained across different APIs. Moreover, the API Mocking capability allows teams to simulate operations without needing the actual code, facilitating testing and development. The Domains feature is particularly useful as it enables the storage, reuse, and referencing of common OAS syntax across various APIs, driving efficiency in the development process. Centralizing API design and development within one platform fosters seamless collaboration among team members on new projects and simplifies the discovery of existing APIs. Managing the complete API lifecycle through a single, cloud-hosted internal repository not only improves accessibility but also enhances coordination among team members. By adopting SwaggerHub, teams can greatly elevate their workflow, stimulate creativity, and drive innovation in the realm of API development, resulting in more effective and cohesive projects.

StepZen provides an innovative low-code approach to creating GraphQL APIs that can seamlessly connect with a variety of data sources such as REST, SQL, NoSQL, SOAP/XML, and even other GraphQL APIs. By issuing a straightforward command, users can specify their backend, which StepZen then automatically introspects to generate the required schema. After this initial creation, the schema can be easily customized with minimal coding, leveraging powerful directives like @rest and @dbquery, or users can opt to construct a schema from scratch. Additionally, the @materializer directive allows for the integration of multiple graphs, promoting the scalable adoption of GraphQL across various teams and domains. This functionality streamlines operations by reducing the need to tackle complexities across subgraphs, thus avoiding issues related to type stubs and other complications. Whether you need an independent graph or a federated graph-of-graphs, deploying it to StepZen's robust cloud infrastructure can be achieved with a single command. Moreover, the platform boasts built-in capabilities for automatic parallel execution, enhanced security and oversight of APIs and data, as well as optimizations for improved performance and reliability. As a result, StepZen guarantees that your GraphQL infrastructure remains secure and stable, enabling you to focus on achieving your business goals without interruptions. With these extensive features, StepZen is well-equipped to significantly enhance the efficiency of your API development process, making it a valuable tool for developers.

Develop modular APIs using a zero-trust framework and deploy them in a serverless manner, irrespective of any existing legacy systems. Constructing a reliable infrastructure presents significant challenges; even highly skilled teams may struggle to follow architectural designs due to the fast-evolving requirements and the intricacies of modern technology. Typegraphs function as programmable virtual graphs that encapsulate all aspects of your system architecture, allowing for the seamless integration of APIs, storage solutions, and business logic while maintaining type safety. Typegate serves as a distributed HTTP/GraphQL query engine that efficiently compiles, optimizes, executes, and caches queries on typegraphs, simultaneously managing authentication, authorization, and security protocols on your behalf. You can effortlessly incorporate third-party dependencies and leverage existing components, facilitating a smoother development experience. The Meta CLI boosts your productivity by offering live reloading capabilities and enabling one-command deployment to Metacloud or any personal environment you choose. Additionally, Metatype fills a significant void in the technological landscape by introducing an innovative approach to creating agile, developer-focused APIs that can adapt to increasing demands. By harnessing these cutting-edge tools, you can not only enhance your development efficiency but also respond more rapidly to the dynamic shifts in the tech ecosystem. This adaptability is essential in a world where technology is constantly evolving, ensuring your solutions remain relevant and effective.

Enjoy effortless navigation through a clean and structured interface that allows you to focus on crucial elements for efficiently testing and collaborating on APIs. Firecamp boasts a user-friendly design complemented by a broad array of powerful features that streamline the API development process and enhance collaboration among team members. You have the flexibility to dynamically set variable values across the platform, promoting consistency and simplifying access. Moreover, you can craft visually appealing API documentation to share not just with your team, but also with the larger community. Perform API Collection Tests directly from the terminal or seamlessly integrate them into your CI/CD pipeline, all while testing and troubleshooting your authentication endpoints with support for various authentication methods. This holistic approach not only enhances productivity but also nurtures a collaborative atmosphere for API development, ensuring that all team members can contribute effectively. Furthermore, the platform continually evolves to incorporate user feedback, making it an ideal choice for developers seeking to improve their workflow.

Testfully provides a wide range of features, including a powerful API client and advanced testing and monitoring tools. Users benefit from flexible storage options, both in the cloud and offline, which facilitate smooth collaboration among teams and enable easy migration, all through a single, comprehensive multi-platform solution. The platform enhances the process of moving data from Postman or Insomnia for effortless integration into Testfully. With an emphasis on adaptability and security, it allows users to define global, environment, and folder variables that can be customized for specific workspaces or individual accounts. Furthermore, users have the ability to tailor authentication methods, parameters, headers, and body content easily, making it simple to craft any HTTP request. Team collaboration is seamless as members can be invited, assigned distinct roles, and folder permissions can be effectively managed. Testfully accommodates major authorization protocols like OAuth2, providing secure access management capabilities. This makes it suitable for users tackling both simple tasks and complex scenarios, as the tool simplifies the testing process without necessitating any programming knowledge, making sophisticated API testing more accessible and user-friendly. Users also have the option to execute requests in a folder simultaneously, sequentially, or in random order with just one click, which significantly boosts efficiency. In addition, it supports response validation and contract testing using a declarative format, further reducing the need for coding and enhancing the overall testing experience. Ultimately, Testfully is crafted to serve both beginners and seasoned professionals, ensuring that all users can effectively harness its powerful features. Moreover, its intuitive interface allows for a quick learning curve, making it easier for newcomers to get started.

Discover exceptional API documentation that is admired by teams and users alike. At last, you have the opportunity to craft API documentation that your whole team can take pride in. Within seconds, you can launch visually striking API reference documents and make customizations in just a few minutes. Developers will be instantly pleased with crucial features, including three-panel layouts, an interactive try-it console, automatically generated code snippets, SEO enhancements, and a user-friendly search function. It's common knowledge that outdated documentation and scope creep may lead to dissatisfaction. Keep your API documentation current by seamlessly integrating your preferred source control with our cloud-based workflows. Our platform accommodates a diverse array of choices, from on-premise solutions to various API management systems. You can establish a comprehensive developer portal in minutes, utilizing your API definitions as valuable resources. Amplify the user experience with tutorials, quick-start guides, and developer tools, all while enjoying extensive customization capabilities. Ensure your API definitions undergo validation, linting, and seamless bundling, enabling the creation of consistently on-spec OpenAPI documents. Connect your API reference and meticulously adjust every detail to captivate your API consumers, ultimately nurturing a more engaging and productive environment for developers. With these features, your documentation will not only fulfill its intended purpose but also evolve into a crucial asset for fostering long-term collaboration and innovation. Embrace these tools to elevate your API documentation to new heights of excellence.

Leverage the benefits of contract-driven development to speed up the creation and deployment of your microservices and micro frontends with assurance. By adopting a left-shift strategy and eliminating the reliance on conventional integration tests, you can employ API specifications as actionable contracts that highlight compatibility issues among your microservices early on in the development cycle. This methodology facilitates simultaneous development, drastically cutting down cycle times and empowering you to introduce products to the market faster than ever. As integration testing progresses, the likelihood of encountering integration challenges is significantly diminished, resulting in a smoother, more resilient, and efficient workflow. Encourage teamwork between your frontend and backend teams by effortlessly aligning on API designs and specifications. Quickly convert your API specifications into tests without incurring additional costs or writing any code, allowing you to run them against your services to proactively identify integration issues. Furthermore, our cutting-edge “no code” technique enables you to detect backward-incompatible changes simply by comparing two versions of the API specification, which further streamlines your development process. This approach not only improves collaboration among team members but also fosters a more nimble and adaptable development ecosystem, ultimately enhancing the overall quality of your projects. With these tools at your disposal, you can ensure that your development team is always aligned and ready to tackle new challenges effectively.

Sparrow offers a robust suite of tools aimed at optimizing the entire API lifecycle, assisting research and development teams in achieving superior outcomes in design-first API creation. Users can leverage cURL to effortlessly send API requests while utilizing vital methods like GET and POST. The platform enhances API interactions by effectively handling headers, data, and authentication processes. As an open-source collaborative platform for API development, Sparrow facilitates the efficient creation of exceptional APIs. With teamwork at the forefront, developers can enhance their methodologies early in the development timeline, leading to stronger APIs and quicker delivery times. Additionally, users benefit from smooth parallel testing across multiple environments, enabling them to collect crucial insights in real-time. Sparrow also provides powerful tools for securing and managing API data, along with self-hosting options that allow full control over testing environments. Moreover, developers can stay updated with the latest enhancements, insights, and resources offered by Sparrow, enriching their overall development experience. This dedication to ongoing improvement guarantees that developers have access to the most effective practices and cutting-edge innovations in the realm of API development, fostering a culture of continuous learning and adaptation.

Flowcode combines the simplicity of visual programming with the powerful functionality of conventional coding, allowing users to swiftly create applications while overseeing the essential infrastructure. This integration helps developers focus on resolving intricate logical problems. Featuring a user-friendly drag-and-drop interface, the platform provides robust logic-driven nodes that simplify the process of visually tracing API calls, which aids in faster bug identification. In addition, Flowcode supports easy management of versions, rollbacks, and updates, ensuring a smooth user experience throughout. The platform also allows for the integration and orchestration of multiple AI models, enabling the development of customized AI APIs. Built on Flyde, which is an open-source visual programming language, Flowcode works within VS Code and integrates seamlessly with existing TypeScript code, web browsers, and Node.js environments. Users can tackle simple tasks using visual flows while exploring complex logic through custom code nodes. Furthermore, it offers options for exporting data and APIs for deployment on private servers, providing both independence and flexibility. Managing database tasks is simplified with abstracted PostgreSQL connections, and users have the capability to connect to other databases to meet specific needs, creating a dynamic programming environment. Ultimately, the synergy of these features empowers users to enhance their creativity and optimize their workflows in an effective manner. This comprehensive approach ensures that developers can adapt to changing requirements while maintaining high productivity levels.

Hoppscotch streamlines the creation and testing of APIs, allowing for faster product launches and enhanced efficiency. You can build APIs rapidly, perform instant tests, and automatically document and share your projects with ease. Whether you're working on initial prototypes or preparing for final production, everything you need for smooth API development is conveniently provided by Hoppscotch, eliminating the need to switch between multiple tabs. The platform allows for the establishment of dedicated workspaces tailored for your teams, offering customizable access controls as necessary. Real-time collaboration with colleagues is facilitated, leading to improved teamwork and productivity. Additionally, you have the option to deploy Hoppscotch on your own servers, providing you with greater flexibility and control. Organizing requests into collections or folders makes it easy to share with team members, while managing environment variables ensures consistency throughout your projects. You can also maintain a comprehensive record of your request history for quick reference. With the ability to modify headers, authenticate requests, generate random data, and explore an array of other features, thorough API testing is easily achievable, including writing assertions to verify responses. Hoppscotch accommodates over 30 languages, making it accessible in your preferred language. You can monitor all activities within your workspace, noting who performed actions and when, enhancing accountability. The integration of your existing SSO provider simplifies login processes, allowing for efficient user, workspace, and resource management. Moreover, the platform’s user-friendly interface ensures that both beginners and seasoned developers can navigate it without difficulty, making API development a more enjoyable experience overall. This comprehensive suite of features, combined with its adaptability, truly makes Hoppscotch a valuable tool for any development team.