aid: fern-api url: https://raw.githubusercontent.com/api-evangelist/fern-api/refs/heads/main/apis.yml name: Fern kind: company description: >- Fern is a developer-tools platform that turns a single API specification into idiomatic client SDKs, beautiful API documentation, and MCP servers. Given OpenAPI, AsyncAPI, gRPC/Protobuf, or Fern's own Fern Definition as input, Fern generates type-safe SDKs in TypeScript, Python, Go, Java, C#, PHP, Ruby, Swift, and Rust, publishes them to registries like npm, PyPI, and Maven, and builds a hosted docs site with an interactive API reference, API playground, and an AI-powered "Ask Fern" search. The primary interface is the open-source `fern` CLI (Apache-2.0, github.com/fern-api/fern) driving a hosted platform - the fern-api catalog documents Fern's SDK-generation, documentation-generation, and Fern Definition capability surfaces as capability areas, plus the one hosted public REST API Fern exposes to customers, the Ask Fern API. Fern is open-core: the CLI and generators are open source, and Docs and SDKs are sold on Hobby (free), Team, and Enterprise plans. image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg tags: - API Lifecycle - SDK Generation - Client Library - API Documentation - Developer Tools - OpenAPI - CLI - Open Source - Developer Experience created: '2026-07-11' modified: '2026-07-11' specificationVersion: '0.19' apis: - aid: fern-api:fern-api-sdk-generation name: Fern SDK Generation tags: - SDK Generation - Client Library - Developer Tools - API Lifecycle image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg humanURL: https://buildwithfern.com/learn/sdks/overview properties: - url: https://buildwithfern.com/learn/sdks/overview type: Documentation - url: https://buildwithfern.com/learn/cli-api-reference/cli-reference/commands type: APIReference - url: https://github.com/fern-api/fern type: SourceCode description: >- Capability area (CLI/platform, not a hosted REST API) that generates idiomatic, type-safe client SDKs in TypeScript, Python, Go, Java, C#, PHP, Ruby, Swift, and Rust from OpenAPI, AsyncAPI, gRPC, or Fern Definition input. Driven by `fern generate`; SDKs are published to GitHub and registries (npm, PyPI, Maven). Endpoints are modeled from the CLI surface rather than a public REST API. - aid: fern-api:fern-api-documentation name: Fern API Documentation tags: - API Documentation - Developer Portal - Docs as Code - Developer Experience image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg humanURL: https://buildwithfern.com/learn/docs/getting-started/overview properties: - url: https://buildwithfern.com/learn/docs/getting-started/overview type: Documentation - url: https://buildwithfern.com/learn/docs/api-references/generate-api-ref type: APIReference - url: https://github.com/fern-api/fern type: SourceCode description: >- Capability area (CLI/platform) that builds a hosted documentation website with a generated API reference, interactive API playground, changelogs, versioning, keyword search, and docs-as-code (Markdown + git) authoring. Driven by `fern generate --docs` and `fern docs dev`. Endpoints are modeled from the CLI and platform surface rather than a public REST API. - aid: fern-api:fern-api-definition-cli name: Fern Definition and CLI tags: - CLI - API Design - API Lifecycle - Developer Tools image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg humanURL: https://buildwithfern.com/learn/cli-api-reference/cli-reference/commands properties: - url: https://buildwithfern.com/learn/cli-api-reference/cli-reference/commands type: Documentation - url: https://buildwithfern.com/learn/api-definitions/openapi/authentication type: APIReference - url: https://github.com/fern-api/fern type: SourceCode description: >- Capability area covering Fern's open-source (Apache-2.0) command-line interface and the proprietary Fern Definition API-description format. Core commands include `fern init`, `fern check`, `fern generate`, `fern login`, `fern token`, `fern export`, and `fern docs dev`. Endpoints are modeled from the CLI surface, not a hosted REST API. - aid: fern-api:fern-api-ask-fern-api name: Ask Fern API tags: - AI - Search - REST API - Developer Tools image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg humanURL: https://buildwithfern.com/learn/docs/ai-features/ask-fern/api-reference/overview baseURL: https://fai.buildwithfern.com properties: - url: https://buildwithfern.com/learn/docs/ai-features/ask-fern/api-reference/overview type: Documentation - url: https://buildwithfern.com/learn/docs/ai-features/ask-fern/api-reference/website/get-website-status type: APIReference - url: openapi/fern-api-openapi.yml type: OpenAPI - url: collections/fern-api.postman_collection.json type: PostmanCollection - url: collections/fern-api.opencollection.json type: OpenCollection description: >- Fern's hosted public REST API for the AI-powered "Ask Fern" documentation search. Index a documentation website, poll indexing job status, and query the indexed content for grounded, hallucination-resistant answers to build your own support integrations. Authenticated with a Bearer token from `fern token`; available on Team and Enterprise plans. The website index/status endpoints are grounded in the published reference; the /ask query shape is modeled. common: - type: AgenticAccess url: agentic-access/fern-api-agentic-access.yml - type: Authentication url: authentication/fern-api-authentication.yml - type: GitHubOrganization url: https://github.com/fern-api - type: LinkedIn url: https://www.linkedin.com/company/buildwithfern - type: Website url: https://buildwithfern.com - type: Documentation url: https://buildwithfern.com/learn/home - type: Plans url: plans/fern-api-plans-pricing.yml - type: RateLimits url: rate-limits/fern-api-rate-limits.yml - type: FinOps url: finops/fern-api-finops.yml - url: https://buildwithfern.com/blog type: Blog maintainers: - FN: Kin Lane email: kin@apievangelist.com