Best Free API Documentation Tools

Compare the Top Free API Documentation Tools as of January 2025

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What are Free API Documentation Tools?

API documentation tools are software tools that help developers create, maintain, and publish documentation for their Application Programming Interfaces (APIs). These tools streamline the process of explaining how to use an API, providing code examples, and outlining endpoints, parameters, and response formats. Many API documentation tools automatically generate docs from the codebase or integrate with frameworks to keep documentation up to date with API changes. They often include interactive features, like live testing or sandbox environments, allowing developers to experiment with API requests directly from the documentation. Ultimately, these tools improve the developer experience by making it easier to understand and use APIs effectively. Compare and read user reviews of the best Free API Documentation tools currently available using the table below. This list is updated regularly.

1

Docsie

Docsie

Docsie is an award-winning digital documentation and knowledge management platform based in Ontario, Canada. You can access Docsie through a SaaS web application to create & edit documentation from any location. Then, you can publish content to a dynamic knowledge portal that users can access whenever they need information! Docsie offers powerful business-grade features to write & manage product documentation: - Docsie Pilot onboarding - Custom portal design & optional training for paid plans - Internal & external portal for employees & end-users - Workspaces - Knowledge base analytics & user feedback collection - Free custom domain - Markdown import & export - WYSIWYG Editor - iFrame embed - SwaggerAPI import - Snippet, fragment, document & topic templates - Help center & in-app help interface - Guided tour builder - Version & language management - Webhooks - AI translation & content generation - Project management - RBAC/JWT/SSO for security

Starting Price: $39 per month (annual)

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2

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.

25 Ratings

Starting Price: $12 per user per month

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3

Zuplo

Zuplo

We’re reinventing API management for everybody, from startups to enterprises. Add authentication, analytics, rate-limiting, and developer documentation to your APIs in minutes. Protect your API by adding rate-limiting with Zuplo in minutes, and add over 50 available plugins like authentication to your API with a single click. Zuplo was built on the edge and deployed to +300 data centers in the world, which makes multi-cloud deployments first-class. With Zuplo you can run different workloads in different clouds while enforcing a unified set of API policies. Zuplo is the only API gateway that runs your OpenAPI spec directly. Leverage the OpenAPI ecosystem to build your API, and then deploy it to Zuplo without additional configuration. Zuplo automatically generates beautiful docs for your API. You can customize the docs with markdown and devs can self-serve API Keys directly from your docs.

1 Rating

Starting Price: $0 per month

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4

Contentrain

Contentrain

Contentrain is the first scalable content management platform combining Git and Serverless platforms. Harness the power of Git Architecture and the scalability of Serverless Platforms to streamline content management and collaboration on various digital platforms for developers and content creators. With the GIT version control system, collaboration is streamlined, while the integration of Serverless Platforms ensures real-time updates and scalability. Contentrain is the best solution for Markdown based content rich websites and also serves as a versatile solution for different use cases: - Document-driven web projects - Internal or external API Documentation - API references - Product overviews - Engaging marketing campaign websites - Modern startup landing pages - Jamstack websites - Multi language websites - RFP portals & Knowledge bases - PWA's - E-commerce websites - Blogs & Publishing platforms - Mobile application contents

1 Rating

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5

Apidog

Apidog

Apidog is a complete set of tools that connects the entire API lifecycle, helping R&D teams implement best practices for API Design-first development. Design and debug APIs in a powerful visual editor. Describe and debug easily with JSON Schema support. Automate API lifecycle with Apidog's test generation from API specs, visual assertion, built-in response validation, and CI/CD. Generate visually appealing API documentation, publish to custom domain or securely share with collaborative teams. Local and cloud mock engine generate reasonable mock data according to field names and specifications without writing scripts. Quality tools have the power to unite your entire team, while ensuring that no task is needlessly repeated. Effortlessly describe your API as you test it, and generate JSON/XML schemas with a simple click. Generate test cases from APIs, add assertions visually, and create test scenarios with branches and iterations easily.

1 Rating

Starting Price: $9 per user per month

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6

Archbee

AiurLabs

Documentation tool for high-performing teams. Archbee is the place to centralize your company's information. Unify knowledge in product, engineering, support, marketing, sales. Usecases: • Manage team knowledge • Developer & API docs • Documentation sites • Document internal processes • Collaborate on documents • Onboard & train teammates • Create documentation for your customers • Bring your own domain Integrations: Slack, Airtable, Loom, Trello, Lucidchart, Typeform, Mindmeister, Prezi, Miro, Google Docs, Google Sheets, Google Slides, Figma, Invision, Framer, Abstract, Marvel, Github, GraphQL, Swagger/Open API, Numeracy, Mode Analytics, Codepen, Intercom, Google Analytics.

Starting Price: $30 per month

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7

Treblle

Treblle

Treblle: A lightweight SDK for accelerated REST-based API development, see metadata for every API request with real-time API traffic monitoring, get powerful analytics and API governance features alongside API automated docs, and automated API security audits for every single request. Simplify workflows, enhance security with support for 18+ languages and frameworks for seamless integration. Empower your teams to build, ship, and maintain APIs faster.

Starting Price: $99 per month

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8

Bump.sh

Bump.sh

Bump.sh is the place for API developers to centralize all of their API documentation. Working with REST, Event-Drivent Architecture, or a mix of API technologies? Bump.sh is the only tool on the market that supports OpenAPI/Swagger, AsyncAPI, and soon more (such as GraphQL, SOAP, and gRPC). Plug Bump.sh into your CI, use our CLI, or upload your specification files manually, and benefit from a stunning UI that definitely contrasts with the legacy tools on the market. Enjoy all of the nifty UX details: we know devs will like it, as they were imagined by devs. Unique on the market: every time you publish a new version of your API documentation, Bump.sh automatically detects changes, publishes a changelog, and sends alerts to subscribe readers if the changes break anything.

Starting Price: $149 per month

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9

Docuo

Spreading

Docuo is an All-in-one tool documentation platform. It is a SaaS platform that helps you to build a great self-service knowledge base for your customers and internal users (public or private knowledge bases). It can Elevate your team's capabilities with one powerful documentation tool. Eliminate fragmented workflows, consolidate tasks, and supercharge efficiency. Benefits of using Docuo: —AI-Assisted Writing：Docuo Copilot automates documentation writing so developers can focus on coding, not writing. —Cross-Team Collaboration: Enable seamless collaboration so your developers and tech writers can co-create stellar documentation with ease. —Easy-to-use Editor: Intuitively embed images, videos, code and more. Customizable blocks make rearranging content effortless. —Hassle-Free Doc Management: Centralize docs for all products enabling effortless version control. —Publish Docs Sites: Docuo handles optimizations for responsiveness, mobile-friendliness and SEO

Starting Price: $31/month/team

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10

Read the Docs

Read the Docs

Spend your time on writing high quality documentation, not on the tools to make your documentation work. Read the Docs simplifies software documentation by automating building, versioning, and hosting of your docs for you. We will host your documentation for free, forever. There are no tricks. We help over 100,000 open source projects share their docs, including a custom domain and theme. Whenever you push code to your favorite version control service, whether that is GitHub, BitBucket, or GitLab, we will automatically build your docs so your code and documentation are never out of sync. We build and host your docs for the web, but they are also viewable as PDFs, as single page HTML, and for eReaders. No additional configuration is required. We can host and build multiple versions of your docs so having a 1.0 version of your docs and a 2.0 version of your docs is as easy as having a separate branch or tag in your version control system.

Starting Price: $5 per month

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11

Stoplight

Stoplight

Stoplight is an API Design, Development, and Documentation platform. Use Stoplight Platform to enable consistency, reusability, and quality in your API lifecycle, all with an easy, enjoyable developer experience. Here's what you can do with Stoplight Platform: - Design APIs with our easy visual designer, Stoplight Studio - Mock API designs automatically with Stoplight Prism mocking - Collaborate on your designs and invite internal and external users to provide feedback - Develop faster and better APIs - Test and enforce against style guides with Stoplight Spectral - Document both internal and external APIs automatically to create a delightful experience Utilize and integrate design-first workflows to quickly scale up standardized, collaborative, and well-governed API programs.

Starting Price: Free

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12

Mintlify

Mintlify

Stop wrestling with outdated documentation. Integrate documentation into your CI/CD to move faster as you scale. Link your documentation with relevant code snippets and owners. Detect when documentation is out of date from code changes or user engagement. Configure alerts to be notified when documentation requires maintenance. Whether it is internal docs on Notion or external docs on ReadMe, we have integrations to support it. Be notified when documentation is out of date or resolve alerts when it has been properly updated. Detect how users engage with your documentation to improve its readability and clarity. Improve code readability without clustering your codebase with comments. Tag documentation ownership to those responsible of the code - or have it automatically detected.

Starting Price: $40 per month

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13

Hashnode

Hashnode

Create and grow your developer blog, newsletter, or team engineering blog effortlessly with Hashnode. Level up your writing using powerful AI features. Blogging platform optimized for software developers and technical writers. Super-fast and SEO-optimized blogs built for developers and tech enthusiasts. Hashnode blogs are fast, up-to-date with SEO techniques, and score above 90 on all Lighthouse parameters. They're simple, elegant, and user-friendly. Own your traffic. Blog for free on a custom domain! Don't blog on rented URLs. Map your custom domain to your Hashnode blog for free and own your traffic. True content ownership. Automatic GitHub backup and publishing. Publish articles from your GitHub repository to your Hashnode blog and backup your Hashnode articles to GitHub like a pro. Create and scale developer documentation and API references that are as dynamic as your code. Built for teams that need full control, customization, and Stripe-level quality.

Starting Price: $199 per month

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14

Theneo

Theneo

Unlock the full potential of AI-powered API documentation. Create stunning, low-maintenance, and engaging docs with a single upload. Import your API collection manually or automatically with a little help from our integration tools for your favorite platforms like Postman. Whether you're building a REST, GraphQL or any other API, we've got you covered. Generates detailed descriptions and summaries for superior API documentation. Ensures flawless, up-to-date documentation. Effortless content search and auto code generation. Automatically update documentation when code changes. Extensions are available for Github, Gitlab, Bitbucket, VS Code, Postman, and more. Customize the appearance of your API docs. Adjust colors and visual elements to match your branding. Make documentation look like part of your website. Effortlessly create and maintain beautiful API docs with simple commands, right from your favorite development tools and source code editors.

Starting Price: $120 per month

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15

SwaggerHub

SmartBear

SwaggerHub is an integrated API design and documentation platform, built for teams to drive consistency and discipline across the API development workflow. Accelerate your team’s design process without any loss in quality or organizational style consistency with a powerful Editor that’s fully compliant with the latest Swagger (OpenAPI) standards. A Powerful Editor equipped with smart error feedback and syntax auto-completion. Style Validators for ensuring design consistency across multiple APIs. API Mocking to virtualize operations without any code. Domains for storing, reusing and referencing common OAS syntax across multiple APIs. Have your API design and development centralized on a single location, allowing your teams to seamlessly collaborate on new APIs, or discover existing APIs on a centralized platform. Coordinate your entire API lifecycle from a central internal repository, hosted on the cloud.

Starting Price: $90 per month

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16

Dash

Kapeli

Dash gives your Mac instant offline access to 200+ API documentation sets. Dash is an API documentation browser and code snippet manager. Dash instantly searches offline documentation sets for 200+ APIs, 100+ cheat sheets, and more. You can even generate your own docsets or request docsets to be included. Dash comes with 200+ offline documentation sets. You can choose which documentation sets to download and Dash will take care of the rest, making sure they are kept up to date. You can also generate your own docsets, request docsets or download docsets from third-party sources. All documentation sets have been generated and are maintained with the utmost care. Dash integrates with package managers to generate documentation sets for anything you might need, as well as provide custom documentation sources of their own. Store snippets of code. Easily reuse snippets. Expand snippets in any app. Organize snippets with tags, syntax highlighting, and variable placeholders.

Starting Price: Free

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17

Alphadoc

Alphadoc

Your open API spec is at the core of Alphadoc, create tutorials and intuitive sequence diagrams on top of it. Always in sync with your OAS spec through versioning. We will help you document your SDKs, long code snippets, and entire demo applications. Easily create code walkthroughs, combining API references, variables and more. Interactive docs let developers try out API calls with real data, and from your documentation and guides. With auto-updating endpoints on your pages, you can effortlessly describe API calls without the need for manual copying and pasting. We provide you with the building blocks to create intuitive documentation. You can also embed endpoints, diagrams and code walkthroughs in websites, blogs, or wherever you want.

Starting Price: €150 per month

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18

Redocly

Redocly

Beautiful API documentation loved by teams and API consumers. At last, API documentation your whole team will be proud of. Publish beautiful API reference docs in seconds and style them in minutes. Tick every developer's favorite box right out of the box, three panels, a try-it console, generated code samples, SEO-friendly, even friendlier search. Nobody likes outdated docs and scope creep. Maintain API documentation with your favorite source control integrated with our cloud app workflows. We support them all, including on-premise and API management providers. Launch a developer portal in minutes reusing your API definitions as assets. Add tutorials, quick-start guides, and developer tooling with incredible customization. Validate, lint, and bundle multi-file API definitions. Write always on-spec OpenAPI documents. Plug in your API reference and customize every nook & cranny to wow your API consumers.

Starting Price: $69 per month

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19

Writerside

JetBrains

The most powerful development environment, now adapted for writing documentation. Use a single authoring environment, eliminating the need for a wide array of tools. With the built-in Git UI, an integrated build tool, automated tests, and a ready-to-use and customizable layout, you can focus on what matters most, your content. You can now combine the advantages of Markdown with those of semantic markup. Stick to one format, or enrich markdown with semantic attributes and elements, Mermaid diagrams, and LaTeX math formulas. Ensure documentation quality and integrity with 100+ on-the-fly inspections in the editor as well as tests in live preview and during build. The preview shows the docs exactly as your readers will see them. Preview a single page in the IDE, or open the entire help website in your browser without running the build. Reuse anything, from smaller content chunks to entire topics or sections of your TOC.

Starting Price: Free

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20

DapperDox

DapperDox

DapperDox is open source, and provides rich, out-of-the-box, rendering of your OpenAPI specifications, seamlessly combined with your GitHub flavoured Markdown documentation, guides, and diagrams. Publish your API Swagger specifications like never before. Document multiple API specifications as a suite of products, and cross-reference as required. The built-in API explorer enables API experimentation from within the documentation pages, and can seamlessly integrate into your authentication and API key model. DapperDox can proxy your developer platform, allowing full integration of API key generation and management alongside your specifications and guides. Change themes and present your documentation in the style you like. DapperDox was created by API documentation authors for one purpose, to improve the quality and usability of the API documentation they were providing for other developers.

Starting Price: Free

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21

RapiDoc

RapiDoc

Free of any frameworks, setups, configs, build steps, or packaging. Can be used with any framework or just with vanilla Javascript. Style it to your heart's content. Change font, logo, colors, and theme. Inject external HTML or embed it into another HTML document. Create beautiful, customizable, interactive API documentation from OpenAPI specification. Use It just like any other HTML tag, Change its attribute using JavaScript and see it react to those changes. Basic knowledge of HTML is all that's required. Minimal dependencies, no runtime, and no virtual DOM ensure the lowest memory consumption, Just the native and raw speed of modern browsers. Loved by tech writers, designers, dev-ops, testers, and developers alike, due to its simplicity, interoperability, and powerful features. No special build-steps, runtime, or framework are required. Comes with built-in console to Try out the APIs. Supports authentication mechanism. No validation ensures you can test negative cases.

Starting Price: Free

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22

Swagger Codegen

SmartBear

Swagger Codegen can simplify your build process by generating server stubs and client SDKs for any API, defined with the OpenAPI (formerly known as Swagger) specification, so your team can focus better on your API’s implementation and adoption. Moving from design to development has never been easier with Swagger Codegen in SwaggerHub. API Definition files can be used to create stubs in popular languages, like Java, Scala, and Ruby, with just a few clicks.

Starting Price: Free

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23

NSwag

Rico Suter

NSwag is a comprehensive Swagger/OpenAPI 2.0 and 3.0 toolchain for .NET, .NET Core, ASP.NET Core, and TypeScript, written in C#. It enables developers to generate OpenAPI specifications from existing API controllers and create client code from these specifications. NSwag combines functionalities similar to Swashbuckle (for OpenAPI/Swagger generation) and AutoRest (for client generation) into a single toolchain, eliminating the need for both. Key features include the ability to generate Swagger 2.0 and OpenAPI 3.0 specifications from C# ASP.NET (Core) controllers, serve these specifications via ASP.NET (Core) middleware with integrated Swagger UI or ReDoc, and generate C# or TypeScript clients/proxies from the specifications. NSwag offers multiple usage methods, including a user-friendly Windows GUI (NSwagStudio), command-line interfaces compatible with Windows, Mac, and Linux, and integration into C# code via NuGet packages.

Starting Price: Free

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24

REST United

REST United

REST United is a platform that simplifies the process of generating Software Development Kits (SDKs) for REST APIs across multiple programming languages, including PHP, Python, Ruby, ActionScript (Flash), C#, Android, Objective-C, Scala, and Java. In just five simple steps, users can create SDKs accompanied by highly customizable documentation featuring easy-to-follow example code, enhancing developer engagement. The platform also leverages the Postman Chrome plug-in to facilitate testing and debugging of REST APIs, streamlining the development workflow. For those designing their own REST APIs using frameworks like Node.js, Ruby Sinatra, Scala Scalatra, or Java JAX-RS, REST United offers assistance in generating server-side code. Support is readily available, with the promise of responses within 12 hours to any inquiries. Overall, REST United aims to make REST API development more accessible and efficient by providing tools that bridge the gap between API design and implementation.

Starting Price: $1 per month

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25

Apiary

Oracle

Write an API in 30 minutes. Share it with your teammates or customers. Let them use the API mock to take your API for a spin--without writing any code. Iterate, rinse & repeat. Coding can wait until you know what your developers really need. DNA for your API, powerful, open sourced and developer-friendly. The ease of Markdown combined with the power of automated mock servers, tests, validations, proxies, and code samples in your language bindings. It's often hard to see how an API will be used until you have the chance to code against it. What wireframes are for UI design, a server mock is for API design. A quick way to prototype an API - even before you start writing code. Two clicks will link Apiary to a repository of your choice. It’s up to you whether you make the API Blueprint private or public and let the community contribute. We update API docs every time you commit, and we push commits to the repo whenever you update your documentation at Apiary. It's a virtuous cycle.

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26

Penify

Penify

Penify automates the software documentation process for Git repositories. Every time a code modification is merged into "main", Penify uses a Large Language Model to generate documentation for the updated code. This automation covers multiple documentation layers, including InCode Documentation, API Documentation, Architectural Documentation, and PR documentation, each designed to improve different aspects of the development process. By taking over the entire documentation process, Penify tackles the common problem of documentation becoming outdated as the code evolves.

Starting Price: ₹835 per month per repository

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27

OpenAPI Generator

OpenAPI Generator

OpenAPI Generator is an open-source tool that automatically generates client libraries, server stubs, API documentation, and configuration files from an OpenAPI Specification (OAS) document. It supports a wide range of programming languages and frameworks, making it easier for developers to integrate APIs into their applications. By automating the creation of boilerplate code, OpenAPI Generator reduces development time and ensures consistency in API interactions. It allows teams to focus on implementing business logic rather than dealing with repetitive tasks like data serialization, deserialization, and HTTP request handling. The tool is widely used in API-driven development, enabling seamless integration of third-party services and simplifying the process of keeping API consumers and providers in sync.

Starting Price: Free

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28

liblab

liblab

Reduce your customers' API integration time by offering SDKs in languages they are familiar with. Our SDK Code Generator creates language-specific SDKs in under a minute and integrates into your CI/CD pipeline for no-touch maintenance with every API update. Generate SDKs in multiple languages with built-in best practices in less than a minute. Integrate them into your CI/CD pipeline to keep SDKs and documentation synchronized with every API update, with no additional engineering effort required. Autogenerate SDKs in Python, Java, Typescript, C#, Go, and PHP with language best practices built in. Easily integrate SDK deployments into your CI/CD pipeline without extra work. liblab automates the process for PyPI, Maven, NuGet, Go, Packagist, and npm.

Starting Price: $120/month

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