Generate beautiful Docs and idiomatic SDKs from your OpenAPI spec. Always in sync as your API evolves.
Your API deserves infrastructure that keeps up with it. Fern generates everything, so nothing ever falls behind.
Fern SDKs handle pagination automatically — list endpoints return an async iterator you can loop over directly.
An AI assistant trained on your content lives on every page. Developers ask questions, get accurate answers instantly — no digging, no support tickets.
Your docs ship as LLM-friendly Markdown, llms.txt, and MCP servers — so every agent and IDE can reason about your API.
Push a spec change. Fern generates updated, idiomatic clients in every language and opens a PR. Your SDK stays current without anyone touching it manually.
SSO, RBAC, private registries, and air-gapped deployment. The compliance and access control your team requires — without a custom implementation.
SDKs, docs, and MCP servers all derive from the same spec. Change one thing upstream and the entire surface regenerates. Nothing drifts, nothing falls out of sync.
When your API powers mission-critical products, the infrastructure around it has to match. Fern gives enterprise teams the reliability, controls, and support they need — without the implementation overhead.
Fern is a mission-critical part of Candid's API. Keeping our docs, SDKs, and server implementation in sync was a nightmare. Fern enabled us to adopt API-first development — our engineers update the spec, run
fern generate, and everything stays perfectly aligned.
The Fern team helped us offer a top-tier developer experience. They embedded with our docs team, migrated over 700+ pages of content, and created an intuitive information architecture across API reference, guides and SDK reference.
Fern automated SDK maintenance, allowing us to support all popular programming languages without needing dedicated engineering resources. Working with the Fern team is like having “McKinsey for APIs” — they bring expert-level guidance in OpenAPI and SDK design.
We used an alternative SDK generator, OpenAPI Generator, for years, and customers constantly complained. Since adopting Fern, customers have migrated rapidly to our new SDKs and have been blown away by the quality.
Partnering with Fern made SDK generation effortless — idiomatic libraries, great docs, and zero maintenance.
Fern is absolutely elite. Fern made it easy for us to single-source our developer resources — from code examples in the docs to our Postman Collection and SDKs. Migrating to Fern was the smoothest migration I've ever experienced, and we were live in under a month.
Fern has been instrumental in delivering an incredible onboarding experience to our customers. We often get compliments in sales calls and during new pilot onboardings about the quality of our docs.
