10 Best API Documentation Tools of 2026

Mintlify ranks first because its free Starter plan covers what most developer relations teams need to launch: 5 editor seats, a custom domain, a web editor, Git sync, an API playground and an MCP server that lets AI agents read the docs. Writers can work in the browser while engineers edit the same content in Git. Pro, at $450 a month billed annually or $540 billed monthly, removes the seat cap and adds preview deployments, Admin APIs, platform and agent analytics, user feedback and the AI Assistant, which uses 25 credits per answer from a 10,000 credit monthly allowance. Enterprise adds SSO, SCIM, RBAC, audit logs, white labeling and self-hosting. The gap between free and Pro is the main drawback: a team that needs analytics or preview deployments jumps straight to a $5,400 yearly bill. Teams that want per-seat pricing at a lower entry point should compare GitBook.

GitBook places second because it combines a visual block editor that product managers and support staff can use with GitHub and GitLab sync that engineers expect. API reference pages are generated from your spec and are interactive, and every published site gets an MCP server. The Free plan is for individuals but already includes Git sync, API docs and preview deployments. Essential costs $65 per site a month billed annually plus $12 per user, and adds team collaboration, a custom domain, analytics, user feedback, redirects and reusable content. Ultimate at $249 per site adds the AI Assistant chat, AI insights, GitBook Agent, adaptive content and authenticated access, with $100 of AI credits included. The pricing model rewards small writing teams and penalizes large ones, because every editor adds $12 a month. SAML SSO and Git Sync IP allowlisting sit in Enterprise.

ReadMe ranks third because it is built specifically for API companies and links docs to how developers use the API. The free Starter plan includes a custom domain, bi-directional sync with your repository, an interactive API reference, usage analytics, LLMs.txt and an MCP server. Pro costs $250 a month billed annually and adds multiplayer editing, branching and reviews, private docs, a landing page, changelog, recipes and forums, custom MDX components and reusable content, plus AI tools such as the ReadMe Agent, AI Linter and AI Writer. The Developer Dashboard keeps 24 hours of API request history, with extended history at $100 a month. Costs add up: Ask AI is a $150 a month add-on, and SAML, audit logs and removing ReadMe branding are reserved for Enterprise. Starter limits doc metrics to 7 days and one published version.

Fern offers the most generous free plan in this comparison for teams publishing API docs. The Free plan covers 10 team members, 1,000 pages, 2,000 page generations a month, a custom domain and subpath, guides, API references and changelogs, an API explorer, a web editor, version and product switching, and Ask Fern, Fern Agent and an MCP server with 250 AI credits a month. It reads OpenAPI, OpenAPI Overlays, Arazzo, AsyncAPI, gRPC, GraphQL and OpenRPC. Fern also generates SDKs, and its site states that Fern is a Postman company. The catch is the jump from Free to Enterprise: there is no published middle plan, so custom CSS, JavaScript and React components, multiple repos, advanced analytics, SSO, SCIM and RBAC all need a sales conversation. Teams that want a priced upgrade path should compare Mintlify or Scalar.

Scalar earns its place because one OpenAPI document drives hosted reference docs, an API client, an SDK and hosted MCP servers. Pro costs $125 a month billed yearly or $150 monthly and includes 5 editor seats, up to 15 APIs, one SDK up to 100 endpoints, custom domains, Git Sync, Markdown and MDX pages, access groups, a full developer portal and 500 Agent Scalar credits. Business at $500 a month billed yearly raises the limits to 25 APIs and 10 editor seats and adds SSO and subpath hosting. Every plan includes one SDK, and extra SDKs cost $150 a month each up to 100 endpoints. The Free plan lists hosted OpenAPI docs and landing pages for up to 3 APIs with 1 editor seat, but Scalar states that after the 7-day trial, publishing a Docs site needs a paid plan. For DevRel teams that also ship client libraries, the combined price is low next to buying docs and SDK tools separately.

Redocly suits teams that treat docs as code. Pro costs $249 a month billed annually and includes unlimited seats, readers and Git contributors, 3 projects, unlimited pages, protected docs, interactive reference docs from OpenAPI, GraphQL and AsyncAPI, a mock server, a custom domain and per pull request previews from GitHub, GitLab, Bitbucket or Azure DevOps. Guides can be written in Markdown or Markdoc, with React for custom pages. Scale at $729 a month billed annually adds SSO, platform RBAC, multi-product sites, an API catalog with scorecards, SDK generation in early access and removes Redocly attribution. The open source Redocly CLI lints and bundles API descriptions, and Redoc CE renders reference docs for free. The trade-off is entry price: there is no free hosted plan, and the browser editor is less central than in GitBook or Mintlify, so it fits teams already comfortable with Git.

Bump.sh focuses on API reference rather than general guides. It publishes doc portals and hubs from OpenAPI, AsyncAPI, OpenAPI Overlays and Arazzo documents, with a CLI and GitHub integration to deploy from CI. Basic costs $50 a month for 10 API docs, 5 MCP tools, 3 internal users and 20 guests, plus a custom domain and logo. Pro at $120 a month raises limits to 30 API docs, 50 MCP tools, 5 internal users and 40 guests, and adds the API Explorer, branches, full CI integration, release rollback, private MCP servers and an automatic changelog. Custom plans add SSO, a reverse proxy and embed mode and a 99.99% SLA. Bump.sh says every plan gets full human support. The limits suit API-first teams with several specs, but teams that need long-form tutorials and a rich editor will want a broader docs platform.

Stoplight approaches documentation from the design side. Its visual OpenAPI and JSON Schema designer lets teams define an API, check it against style guides, mock it and publish interactive docs with a try-it console from the same project. Basic costs $44 a month billed annually with the first 3 users included and $11 for each additional user. Startup at $113 a month adds private projects, multi-branch support, custom domains, theming and Google Analytics, with 8 users included. Pro Team at $362 a month adds shared style guides, self-hosted Git providers, LDAP and SAML SSO and removes Stoplight branding. The editor is aimed at API designers more than writers, so guide-heavy DevRel sites may find GitBook or Mintlify easier. Stoplight also maintains the open source Spectral, Prism and Elements projects.

Theneo covers more API formats than most tools here: REST, AsyncAPI, SOAP, GraphQL and gRPC. Its free Starter plan includes 1 public project, 2 private projects, up to 20 team members, an advanced API explorer, automated changelog generation, project analytics and reader feedback, plus up to 100 AI search results for readers. Business costs $120 a month per workspace billed annually or $150 monthly and adds up to 7 projects, 50 team members, unlimited AI search and TheneoAI, custom branding and SEO, a custom domain and one developer portal. Growth at $400 a month billed annually adds custom CSS, custom AI prompts, up to 20 developer portals, IP allowlisting and Slack or Teams support. Enterprise adds self-hosting and SAML SSO. The free plan suits evaluation, but a branded public docs site needs Business.

Archbee is a general documentation portal that includes API documentation, which suits teams that publish user guides, developer docs and internal process docs in one place. Growing starts at $80 a month billed annually and includes unlimited readers and project spaces, public and private portals, a custom domain and branding, custom JavaScript, password protection, GitHub integration and API documentation. Scaling, from $350 a month, adds complete branding control, a review system, reusable content and variables, versioning and localization and finer reader access control. Enterprise adds SAML and OIDC SSO and AI-assisted translations. Readers are free but extra team members are charged, and there is no free plan. Early-stage companies can apply for 50% off any plan for 2 years. For an API-first DevRel team, versioned docs on Scaling cost more than Mintlify's free tier or Stoplight Basic.