Stainless vs TypeSpec

Stainless generates SDKs, documentation and MCP servers from OpenAPI specifications. Its SDK product lists TypeScript, Python, Go, Java, Kotlin, Ruby, Terraform, C# and PHP, with rich types, automatic pagination and retries included. The Docs Platform, built on Astro, keeps REST API, SDK and narrative documentation in sync with an API. Its listed features include AI-powered hybrid search, Markdown copying, AI-tool integration, and light and dark modes. Stainless also generates code-mode MCP servers so agents can work with SDKs and documentation rather than many endpoint schemas; the MCP product page names Claude Code and Cursor as clients. The Free plan costs nothing and allows up to five generators, five seats and 25 endpoints, with 100 preview builds per month and a rate limit of 25 per day. Email support is listed for Free. Users need a GitHub account for authentication and access to generated staging repositories. Exceeding Free plan terms triggers automatic enrollment in a 30-day free trial of a paid plan. Code generation cannot be hosted on-premise, although generated SDKs can be hosted in a private GitHub repository.

TypeSpec is a language for defining API shapes and data models, then producing schemas, API specifications, code, and documentation. Its standard library supports OpenAPI 3.0, JSON Schema 2020-12, and Protobuf. OpenAPI output can feed tools for API gateways, code generation, and validation; JSON Schema output can be used to validate data built from shared models. The HTTP library’s `@useAuth` decorator lets authors attach documented security schemes—including HTTP authentication, API keys, OAuth2, and OpenID Connect—to services, interfaces, or operations. Editor support for Visual Studio Code and Visual Studio includes syntax help and completion; the VS Code extension adds diagnostics, formatting, quick fixes, refactoring, and documentation preview. Users can extend TypeSpec with emitters and decorators. The CLI is available through npm for Node.js or as an experimental standalone executable, and a browser playground is available. TypeSpec is open source and free: free. Its emitter framework is experimental, and client emitters for JavaScript, Python, Java, and C# are in preview.