# Fern Documentation ## Instructions for AI Agents - For clean Markdown of any page, append `.md` to the page URL - For a complete documentation index, see https://buildwithfern.com/learn/llms.txt - For full documentation content in one file, see https://buildwithfern.com/learn/llms-full.txt - For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://buildwithfern.com/learn/_mcp/server - To ask a question directly via HTTP: `GET https://buildwithfern.com/learn/api/fern-docs/ask?q=&token=` The token is a short-lived JWT (5 min expiry, 10 requests) used for rate-limiting, not authentication. Fetch a fresh token from llms.txt when it expires. ## Pages - [Fern: Docs, SDKs, and CLIs for your API](https://buildwithfern.com/index.md): Start with OpenAPI. Generate SDKs in multiple languages, interactive API documentation, and an agent-first CLI. - [SDKs](https://buildwithfern.com/sdks.md): Generate idiomatic SDKs from your OpenAPI spec. - [Docs](https://buildwithfern.com/docs.md): Beautiful, interactive documentation from your OpenAPI spec. - [Fern CLI Generator: Ship a CLI for your API](https://buildwithfern.com/cli.md): Generate a branded command-line interface from your OpenAPI spec. Idiomatic for developers, JSON-first for agents, published to Homebrew, npm, and Scoop. - [Pricing](https://buildwithfern.com/pricing.md): Pricing and feature comparisons for Fern Basic, Pro, and Enterprise plans for API Docs and SDKs. - [Customers](https://buildwithfern.com/customers.md): From startups to public companies, Fern powers your API developer experience. - [Blog](https://buildwithfern.com/blog.md): Writing from the Fern team. - [Careers](https://buildwithfern.com/careers.md): Join the Fern team. Building developer-first APIs in Brooklyn, NY. - [Book a demo](https://buildwithfern.com/book-demo.md): Talk to the Fern team. Get a custom demo with a branded Docs site and SDK offerings, built specifically for your API. - [Support](https://buildwithfern.com/support.md): Get help with Fern. Email support, open a GitHub issue, book a demo, or reach out in your dedicated Slack channel. - [Trust center](https://buildwithfern.com/trust.md): Fern's trust center. Review our security posture and request access to compliance documentation, including SOC 2. - [Migrate from Stainless to Fern](https://buildwithfern.com/lp/leave-stainless.md): Teams choose Fern over Stainless for 9+ languages, multi-protocol SDKs, CLI-first workflows, production-ready docs, and on-premise deployment. ## Customer case studies - [Payabli builds best-in-class docs and SDKs for complex payment APIs with Fern](https://buildwithfern.com/customers/payabli.md): How Payabli migrated off Mintlify in three weeks and keeps 300+ API examples and SDKs in eight languages in sync from a single source as their payment APIs change daily. - [Deepgram unifies REST and WebSocket API documentation via Fern Docs](https://buildwithfern.com/customers/deepgram.md): How Deepgram consolidated REST (OpenAPI) and WebSocket (AsyncAPI 3.0) documentation into a single developer experience and opened contribution to PMs across the company. - [Frame.io drives API adoption through streamlined docs and SDKs](https://buildwithfern.com/customers/frame.md): How Adobe's Frame.io team shipped SDKs alongside synced documentation and turned auth questions from 90% of their support load into self-serve answers. - [Unleash scales AI-ready documentation with Fern Docs](https://buildwithfern.com/customers/unleash.md): How Unleash migrated 300+ pages off Docusaurus in two weeks and made every doc AI-ready as half their traffic shifted to LLM tools. - [ElevenLabs scales voice AI infrastructure with Fern Docs & SDKs](https://buildwithfern.com/customers/elevenlabs.md): How ElevenLabs unified developer documentation and SDK generation on Fern as their API surface scaled to over a billion end users. ## Blog posts - [Why Fern takes a developer-first approach to SDK generation and API documentation June 2026](https://buildwithfern.com/post/fern-developer-first-sdk-generation-api-documentation.md): Learn why Fern takes a developer-first approach to SDK generation and API documentation in June 2026. Generate SDKs and docs from one spec automatically. - [How to generate a CLI from your OpenAPI spec (June 2026)](https://buildwithfern.com/post/generate-cli-from-openapi-spec.md): Learn how to generate a CLI from your OpenAPI spec in June 2026. Keep commands synchronized with your API automatically without manual coding or drift. - [How 2 designers and AI rebuilt Fern's marketing site](https://buildwithfern.com/post/building-fern-site.md): How we leveraged AI in our design process. We set the creative direction up front and refined the final details ourselves; AI handled the middle of the process. - [The best API documentation platforms for enterprise teams in May 2026](https://buildwithfern.com/post/best-api-documentation-platforms-enterprise.md): Compare the best API documentation platforms for enterprise teams in May 2026. SDK generation, private deployment, and Git-native workflows included. - [Best developer portal platforms for HR tech partner ecosystems (May 2026)](https://buildwithfern.com/post/developer-portal-platforms-hr-tech-partner-ecosystems.md): Compare developer portal platforms for HR tech partner ecosystems. Review SDK generation, compliance controls, and documentation tools for HRIS integrations. May 2026. - [How insurance carriers should build API partner portals in 2026](https://buildwithfern.com/post/insurance-carriers-build-api-partner-portals.md): Learn how insurance carriers should build API partner portals in May 2026 with self-service onboarding, OAuth 2.0, typed SDKs, and sandbox environments. - [Workday, ADP, and Rippling API documentation: A partner-side comparison (May 2026)](https://buildwithfern.com/post/workday-adp-rippling-api-documentation-comparison.md): Compare Workday, ADP, and Rippling API documentation for partner developers. Learn authentication, rate limits, and costs. May 2026 analysis. - [Revamping our website](https://buildwithfern.com/post/revamping-website.md): Investing in the future of developer and agent experience tooling. - [Introducing Fern Replay](https://buildwithfern.com/post/fern-replay.md): Replay reapplies SDK customizations on top of every regeneration, automatically. Available across all SDK languages. - [Migrate from Stainless today](https://buildwithfern.com/post/fern-vs-stainless-sdk-generator.md): Compare Fern vs Stainless SDK generators in January 2026. Fern offers 9+ languages, WebSockets, gRPC, CLI workflow, and on-premise deployment vs Stainless dashboard approach. - [How I'm making our documentation agent-friendly (and how I'm not)](https://buildwithfern.com/post/agent-friendly-docs.md): Writing docs that AI agents can actually use means doing content work and relying on platform scaffolding. Here's what I do, and what I can't. - [API governance and documentation: How enterprise teams stay in sync (May 2026)](https://buildwithfern.com/post/api-governance-documentation-enterprise-sync.md): Learn how enterprise teams keep API governance and documentation synchronized in May 2026. Prevent spec drift with contract-driven development strategies. - [What is an API catalog: Definition and implementation guide (May 2026)](https://buildwithfern.com/post/what-is-api-catalog.md): Learn what an API catalog is, why organizations need one, and how to implement it. Complete definition and implementation guide for May 2026. - [We built a CLI generator for agents and humans](https://buildwithfern.com/post/cli-generator.md): Generate a CLI from the same API spec that powers your Fern Docs and SDKs. Now in early access. - [Different types of APIs guide (April 2026)](https://buildwithfern.com/post/different-types-of-apis-guide.md): Learn different types of APIs including REST, GraphQL, gRPC, and WebSocket. Complete guide for developers covering protocols and access levels in April 2026. - [Add AI chat to documentation (April 2026)](https://buildwithfern.com/post/how-to-add-ai-chat-to-documentation.md): Learn how to add AI chat to your documentation site in April 2026. RAG architecture, vector search, and citation enforcement for trusted developer answers. - [API docs for non-technical users (April 2026)](https://buildwithfern.com/post/api-documentation-for-non-technical-users.md): Learn how to make API documentation accessible for non-technical users with plain language, visual hierarchy, and interactive tools. April 2026 guide. - [Visual editors for technical docs (April 2026)](https://buildwithfern.com/post/visual-editors-technical-documentation.md): Learn how visual editors for technical documentation help teams manage API docs, guides, and tutorials through Git workflows. April 2026 guide. - [From Fern customer to Fern contributor ](https://buildwithfern.com/post/from-fern-customer-to-fern-contributor.md): Barry previously worked at Square for four and a half years, starting on the public-facing GraphQL API platform for external developers. Over time, he moved into the SDK pipeline, which is how he started working with Fern. - [Fern vs ReadMe: Which is better? (April 2026)](https://buildwithfern.com/post/fern-vs-readme.md): Compare Fern vs ReadMe for API documentation in April 2026. See which platform offers better SDK generation, pricing, and developer experience. - [How we built Agent Score to improve Fern Docs](https://buildwithfern.com/post/agent-score.md): Fern built a Lighthouse-style benchmark for AI-agent readiness, ran it on our own docs, and shipped the fixes in public. Here's what we found. - [How to build an API: Complete guide April 2026](https://buildwithfern.com/post/how-to-build-an-api.md): Learn how to build an API with this complete April 2026 guide covering architecture, protocols, endpoints, auth, testing, and documentation best practices. - [What Is an API Endpoint? Guide April 2026](https://buildwithfern.com/post/what-is-api-endpoint.md): Learn what API endpoints are, how they work, and best practices for building and testing them. Complete guide for developers updated April 2026. - [API design best practices guide (March 2026)](https://buildwithfern.com/post/api-design-best-practices-guide.md): Learn API design best practices and principles in this complete guide for March 2026. Covers REST, GraphQL, authentication, versioning, and designing for AI agents. - [API development guide [March 2026]](https://buildwithfern.com/post/api-development-tools-guide.md): Learn API development tools and best practices including spec-first workflows, testing strategies, and SDK generation. Updated March 2026 with latest techniques. - [Why I keep rebuilding the same docs pages](https://buildwithfern.com/post/rebuilding-docs-pages.md): Fern's technical writer, Devin, maintains 500+ pages of documentation for Fern Docs and SDKs, with new features shipping daily. Every time a page needs updating, the content is the obvious part — the components underneath it are the editorial decision most writers don't revisit. - [API Testing Guide for Developers 2026](https://buildwithfern.com/post/api-testing-complete-guide-developers.md): Complete API testing guide for developers in March 2026. Learn automation strategies, testing types, and tools to catch integration issues before users do. - [Prepare APIs for AI agents - March 2026](https://buildwithfern.com/post/prepare-apis-documentation-ai-agent-consumption.md): Learn how to prepare your APIs and documentation for AI agent consumption in March 2026 with OpenAPI specs, llms.txt files, and machine-readable formats. - [API docs with MDX & components (March 2026)](https://buildwithfern.com/post/api-documentation-platforms-mdx-component-support.md): Compare API documentation platforms with MDX and React component support. See which tools offer interactive components, SDK generation in March 2026. - [Best API docs for enterprise security March 2026](https://buildwithfern.com/post/enterprise-security-api-documentation-platforms.md): Compare the best API documentation platforms for enterprise security and access control in March 2026. Features include SSO, RBAC, and self-hosting options. - [Write LLM-friendly docs in March 2026](https://buildwithfern.com/post/how-to-write-llm-friendly-documentation.md): Learn how to write LLM-friendly documentation in March 2026. Serve markdown to AI agents, reduce token use 80-90%, and keep docs accurate with llms.txt files. - [The AI-assisted solo technical writer ](https://buildwithfern.com/post/ai-assisted-technical-writer.md): Fern’s technical writer, Devin, uses AI tools to ship 20,000 new lines of documentation per month about Fern, an open source tool that generates API documentation and SDKs. - [API documentation platforms WYSIWYG March 2026](https://buildwithfern.com/post/api-documentation-writing-platforms-wysiwyg-editors.md): Compare top API documentation writing platforms with WYSIWYG editors in March 2026. See which tools offer visual editing, SDK generation, and Git integration. - [API documentation best practices guide Feb 2026](https://buildwithfern.com/post/api-documentation-best-practices-guide.md): Learn API documentation best practices with real examples. Complete guide for February 2026 covering OpenAPI, AsyncAPI, and spec-first tools to prevent drift. - [API docs with Git integration (Feb 2026)](https://buildwithfern.com/post/api-documentation-platforms-git-integration.md): Compare the best API documentation platforms with version control and Git integration. Updated February 2026 guide to Git-native docs and SDK generation tools. - [API Docs for AI & ML Companies Feb 2026](https://buildwithfern.com/post/api-documentation-platforms-ai-ml-companies.md): Compare the best API documentation platforms for AI and ML companies in February 2026. See which tools support streaming, SDK generation, and AI features. - [Sweating the small stuff in Fern Docs](https://buildwithfern.com/post/ui-fixes.md): Frontend engineer Sarah shares six UI fixes that improved Fern Docs, from smooth arrow animations to flickering sidebar icons. Small transitions matter when developers are trying to focus on your API. - [Docs-as-Code Needs Client Libraries (Feb 2026)](https://buildwithfern.com/post/why-docs-as-code-needs-client-libraries.md): Learn why docs-as-code workflows need client library automation. February 2026 guide to SDK generation, version control, and API documentation synchronization. - [Info Architecture for Docs: February 2026](https://buildwithfern.com/post/information-architecture-best-practices-documentation.md): Learn information architecture best practices for documentation in February 2026. Master nested products, switchers, and navigation patterns for developer docs. - [API Docs for AI Agents: llms.txt Guide May 2026 | Fern](https://buildwithfern.com/post/optimizing-api-docs-ai-agents-llms-txt-guide.md): Learn how to optimize API documentation for AI agents using llms.txt in May 2026. Complete guide to llms.txt implementation for better AI code generation. - [Fern's Rust SDK generator](https://buildwithfern.com/post/rust-sdk-generator.md): Generate production-ready Rust client libraries from your API spec, built for performance-critical applications. - [API Docs Platforms: Style Guide Enforcement 2026](https://buildwithfern.com/post/api-documentation-platforms-style-guide-enforcement.md): Compare API documentation platforms with built-in style guide enforcement. See which tools automate Vale linting and Microsoft/Google style checks in February 2026. - [Generated vs manual docs: Jan 2026 guide](https://buildwithfern.com/post/generated-vs-manual-documentation-which-approach.md): Compare generated vs manual documentation approaches in January 2026. Learn which method keeps your API docs synchronized and prevents drift. - [GitBook Reviews & Alternatives (February 2026)](https://buildwithfern.com/post/gitbook-reviews-pricing-alternatives.md): Compare GitBook pricing, read reviews, and find alternatives. See why teams switch from GitBook to Fern, Mintlify, ReadMe, and Stoplight in February 2026. - [Stainless vs GitBook vs Speakeasy (Jan 2026)](https://buildwithfern.com/post/stainless-vs-gitbook-vs-speakeasy-api-docs-sdk-comparison.md): Compare Stainless, GitBook, and Speakeasy for API documentation and SDK generation in January 2026. See language support, protocols, and deployment options. - [Evergreen SDKs Developer Guide (January 2026)](https://buildwithfern.com/post/evergreen-sdks-developer-guide.md): Learn how evergreen SDKs auto-sync with API specs to eliminate drift and manual maintenance. Automate SDK generation, versioning, and publishing in January 2026. - [Self-Hosted Documentation Tools January 2026](https://buildwithfern.com/post/self-hosted-documentation-tools-enterprise-security.md): Compare self-hosted documentation tools for enterprise security, SOC 2, HIPAA compliance in January 2026. Docker deployment, offline search, SDK generation options. - [Docs Linting Guide - January 2026](https://buildwithfern.com/post/docs-linting-guide.md): Learn docs linting best practices in January 2026. Automate quality checks with Vale, link checkers, and CI/CD integration to prevent broken links and style violations. - [From Fern Customer to Fern Engineer](https://buildwithfern.com/post/fernie-sandeep.md): Sandeep joined Fern as an engineer in Nov '25 after being a Fern customer. He walks you through the conviction you need to make that jump. - [Documentation Maintenance Guide November 2025](https://buildwithfern.com/post/documentation-maintenance-best-practices.md): Learn documentation maintenance best practices for November 2025. Automate API docs, reduce maintenance costs, and keep developer documentation current with proven strategies. - [API Developer Portals for Enterprise (Jan 2026)](https://buildwithfern.com/post/api-developer-portal-enterprise-branding.md): Compare top API developer portal platforms for enterprise branding in January 2026. Features include custom domains, SSO, RBAC, and automated SDK generation. - [Docs-as-Code Solutions for APIs | January 2026](https://buildwithfern.com/post/docs-as-code-solutions-api-teams.md): Compare the best docs-as-code solutions for API teams in January 2026. Review Git-native workflows, SDK generation, and automated API documentation tools. - [Stainless Pricing & Alternatives (January 2026)](https://buildwithfern.com/post/stainless-pricing-alternatives.md): Compare Stainless pricing, reviews, and alternatives in January 2026. Find SDK generators with WebSocket, gRPC support, and multi-language coverage for production APIs. - [Best llms.txt Platforms January 2026](https://buildwithfern.com/post/best-llms-txt-implementation-platforms-ai-discoverable-apis.md): Compare top llms.txt implementation platforms for AI-discoverable APIs in January 2026. Fern, Mintlify, Scalar, ReadMe, and Fumadocs reviewed for automated generation. - [Delivering world-class developer experiences with Postman](https://buildwithfern.com/post/postman-acquires-fern.md): We’re excited to share that Fern has joined Postman. Together, we'll help teams deliver better APIs and better developer experiences. Fern will continue to operate as an independent product. - [Fern vs Speakeasy SDK Generator (May 2026) | Fern](https://buildwithfern.com/post/fern-vs-speakeasy-sdk-generator.md): Compare Fern vs Speakeasy SDK generators in May 2026. Fern supports 9 languages including Swift and Ruby, on-premises deployment, and synchronized docs vs Speakeasy's 5 languages. - [Interactive API Docs with Live Testing Dec 2025](https://buildwithfern.com/post/interactive-api-documentation-tools-live-testing.md): Compare the best interactive API documentation tools with live testing in December 2025. Features include auto-populated auth, WebSocket support, and SDK generation. - [API-First Development Platforms January 2026](https://buildwithfern.com/post/api-first-development-platforms.md): Compare the best API-first development platforms in January 2026. Review SDK generation, documentation tools, and workflows for TypeScript, Python, and more. - [Multi-Audience API Platforms (December 2025)](https://buildwithfern.com/post/multi-audience-api-platform-solutions.md): Compare multi-audience API platforms for public, partner, and internal users. SDK generation, RBAC, and automated publishing solutions reviewed (December 2025). - [AI Agents for Technical Writing (January 2026)](https://buildwithfern.com/post/technical-writing-ai-agents-devin-cursor-claude-code.md): Learn how AI agents like Devin, Cursor, and Claude Code automate technical writing in January 2026. Compare features, workflows, and style enforcement for docs. - [Developer docs metrics that matter Jan 2026](https://buildwithfern.com/post/developer-documentation-metrics.md): Learn which developer documentation metrics actually matter in January 2026. Track time-to-first-API-call, zero-result searches, AI bot traffic, and analytics that improve API adoption. - [API Docs & SDK Generation Tools (May 2026) | Fern](https://buildwithfern.com/post/api-documentation-sdk-generation-tools.md): Compare API documentation platforms that generate SDKs in May 2026. Fern, Speakeasy, Stainless, ReadMe, and more - find tools that automate client libraries and docs. - [MCP Servers for Documentation Sites April 2026 | Fern](https://buildwithfern.com/post/mcp-servers-documentation-sites.md): Learn why MCP servers matter for API documentation sites in April 2026. Understand how they make your docs AI-accessible for Claude, Cursor, and other AI coding assistants developers use daily. - [Open Source vs Closed Source SDK Generators 2025](https://buildwithfern.com/post/open-source-vs-closed-source-sdk-generators.md): Compare open source, closed source, and open-core SDK generation platforms in December 2025. Learn about OpenAPI Generator, Speakeasy, Stainless, and Fern for API SDKs. - [RBAC Guide: Role-Based Access Control December 2025](https://buildwithfern.com/post/rbac-role-based-access-control-guide.md): Learn how RBAC (Role-Based Access Control) secures documentation portals and APIs by granting access based on user roles. Complete implementation guide December 2025. - [Introducing Fern Autorelease: hands-off SDK releases](https://buildwithfern.com/post/fern-autorelease.md): Fern Autorelease automatically detects updates to your API specification, regenerates SDKs, determines version bumps, and publishes new packages. - [Fern vs Mintlify: Which API Tool Wins (2026)](https://buildwithfern.com/post/fern-vs-mintlify.md): Compare Fern vs Mintlify for API documentation and SDK generation in January 2026. Learn which tool offers better client libraries, self-hosting, and access control. - [OpenAPI code generation for enterprise (Nov 2025)](https://buildwithfern.com/post/openapi-code-generation-enterprise.md): Compare the best OpenAPI code generation platforms for enterprise teams in November 2025. Learn about SDK generation, breaking change detection, and compliance features. - [On-prem hosting security benefits November 2025](https://buildwithfern.com/post/on-prem-hosting-security-data-governance-benefits.md): Learn why enterprises choose on-prem hosting for API documentation and SDK generation. Security, compliance, and cost benefits explained for November 2025. - [Best SDK generation tools 2026 | Multi-language APIs | Fern](https://buildwithfern.com/post/best-sdk-generation-tools-multi-language-api.md): Compare the best SDK generation tools for 2026. Build type-safe client libraries for TypeScript, Python, Go, Java & more. Save hundreds of hours. April 2026. - [Best API documentation chat tools May 2026 | Fern](https://buildwithfern.com/post/best-conversational-api-documentation-platforms.md): Compare the best conversational API documentation platforms in May 2026. AI-powered chat interfaces help developers find answers instantly with citations. - [Introducing the Fern Editor - Edit Developer Docs in the Browser, Powered by Git](https://buildwithfern.com/post/fern-editor.md): The Fern Editor makes writing developer documentation accessible to everyone. Non-technical teammates can edit docs in the browser while developers keep Git-backed workflows for review and version control. - [Improved developer docs Agents: Full API specs, traffic analytics, & markdown for LLMs](https://buildwithfern.com/post/llms-txt-improvements.md): See how Fern's improved llms.txt support helps you serve complete API specifications, track AI bot traffic, and reduce token costs by 90% with automatic Markdown serving. - [Multiple products, one docs site: Webflow case study](https://buildwithfern.com/post/webflow-product-switcher.md): See how Webflow scaled from one to five products with a single docs site using Fern's product switcher. Real documentation example with implementation details. - [Fern's Swift SDK Generator: Build idiomatic iOS client libraries](https://buildwithfern.com/post/swift-sdk-launch.md): Fern’s Swift SDK generator is live. Instantly provide iOS developers with an idiomatic Swift client for your API. - [Ask Fern now sits in your documentation's sidebar](https://buildwithfern.com/post/ask-fern-sidebar.md): Three improvements to Ask Fern, the AI assistant for documentation. - [Why we’re launching Fern Self-Hosted Docs and SDKs ](https://buildwithfern.com/post/self-hosted-launch.md): Fern Self-Hosted Docs and SDKs lets enterprises deploy on their own infrastructure, delivering a best-in-class developer experience with the security and compliance they require. - [ Internal documentation at scale: SPS Commerce case study](https://buildwithfern.com/post/sps-commerce-internal-documentation.md): Learn how SPS Commerce built out an internal documentation platform with Fern, allowing their developer team to improve productivity, reduce operational risk, and accelerate delivery. - [Why documentation is now the most important part of your API](https://buildwithfern.com/post/why-is-documentation-important.md): Developer docs are taking off. But why? We dive into the key tailwinds—from the rise of APIs and microservices to the surprising new role docs are playing in an agent-powered world. - [Docs-as-code: What is it, how it works, and ways to start](https://buildwithfern.com/post/docs-as-code.md): Learn about the history of docs-as-code tooling and how it will play a part in the future of AI-powered documentation. - [How Payabli reduced API docs maintenance by 80% with Fern](https://buildwithfern.com/post/payabli-fern-api-docs-case-study.md): Payabli's documentation team reduced API specification management from ~30% to ~5% of their total effort—an 80% reduction that freed them to focus on creating better developer experiences. - [How to generate a TypeScript SDK for your API spec](https://buildwithfern.com/post/generate-typescript-sdk.md): Learn how to deliver a TypeScript SDK that’s lightweight, fully type-safe, and works across all JavaScript runtimes with Fern. - [How we built the Fern site, an honest-take](https://buildwithfern.com/post/fern-site.md): It’s not just a website — it’s a testament to how much we care about craft at Fern. - [Fern raises a Series A to meet the growing demand for SDKs and API Docs](https://buildwithfern.com/post/series-a.md): Today we’re announcing our $9M Series A, led by Bessemer Venture Partners with participation from Y Combinator, bringing our total funding to $13M. - [Announcing WebSocket Support with AsyncAPI v3](https://buildwithfern.com/post/announcing-websocket-support-with-asyncapi-v3.md): With full AsyncAPI support in Fern SDKs and Docs, you can now document your WebSocket endpoints with ease. You can add AsyncAPI next to your OpenAPI for a complete API reference. - [The first autogenerated SDK with gRPC and REST](https://buildwithfern.com/post/pinecone.md): Fern breaks new ground by launching the first generated SDK supporting both gRPC and REST in a single package. Partnering with Pinecone, they delivered an idiomatic C# SDK that streamlines development by combining performant gRPC data operations with REST-based control features, now integrated into Microsoft's Semantic Kernel. - [From handwritten to generated—Cohere's SDK journey](https://buildwithfern.com/post/cohere.md): Cohere partnered with Fern to transform their SDK development from manual TypeScript and Go implementations to automated generation. By centralizing their API spec and leveraging Fern's language-specific code generation, Cohere eliminated SDK maintenance overhead while delivering idiomatic features like TypeScript's discriminated unions and Go's context primitives, reducing GitHub issue resolution time from months to days. - [How Merge uses Fern to ship SDKs](https://buildwithfern.com/post/merge.md): Merge streamlined their SDK development by switching from OpenAPI to Fern, enabling cleaner APIs and automated workflows across six programming languages. The rapid 4-week implementation delivered enhanced documentation and compatibility, earning praise from developers for its simplified integration process. - [How Candid sped up API development by 50% by going schema first](https://buildwithfern.com/post/candid.md): Fern transforms API development at Candid by centralizing API definitions in YAML and automating code generation. This eliminates manual boilerplate across backend (95,000 lines) and frontend (30,000 lines), ensuring consistency between Pydantic models, FastAPI routes, TypeScript clients, and upcoming documentation. The schema-first approach prevents drift bugs through a single source of truth, with plans to extend into customer-facing SDKs.