Stainless
A platform that generates hand-crafted-feeling SDKs, docs, a CLI, and MCP servers automatically from an OpenAPI spec — the same generator behind OpenAI's, Anthropic's, and Cloudflare's official client libraries.
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Description
Publishing an API is only half the job — developers also expect a proper SDK in their language of choice (Python, TypeScript, Go...), and hand-maintaining SDKs across half a dozen languages every time the API changes is a losing battle most teams eventually give up on, letting SDKs go stale. Stainless takes over that maintenance work: feed it an OpenAPI spec, and it keeps idiomatic SDKs in sync automatically, the way a good build pipeline keeps compiled binaries in sync with source code.
Stainless generates SDKs, always-current documentation, a CLI, and MCP servers directly from an OpenAPI specification, across languages including TypeScript, Python, Go, Java, Kotlin, Ruby, C#, PHP, and Terraform. It's notably the generator behind the official SDKs for OpenAI, Anthropic, and Cloudflare — a strong quality signal, since those companies could have built or bought anything. In 2026, the Stainless team joined Anthropic, tying its future roadmap closely to Anthropic's own developer-tooling priorities. There's no public pricing; it targets platform and DevEx teams at companies maintaining APIs across multiple language ecosystems who want SDK quality without the multi-language maintenance burden.
💬 Our review
The short version: Stainless already generates the SDKs for OpenAI and Anthropic, which is about as strong a quality endorsement as this category gets — worth strong consideration if you're maintaining APIs across several language SDKs and tired of them drifting out of sync.
The join-Anthropic move in 2026 mirrors what happened with Bridge and Stripe: strong signal of technical quality and staying power, but it also means Stainless's roadmap now likely prioritizes Anthropic's own needs (MCP servers, agent-facing tooling) alongside general customers, rather than being purely independent. That's arguably good news if your priority is AI-agent-facing SDKs and MCP servers, since that's where Anthropic's interests point. Compared to Fern, its closest direct competitor in the OpenAPI-to-SDK space, the differentiator is real-world validation from OpenAI/Anthropic/Cloudflare rather than a fundamentally different technical approach — get a quote and a side-by-side generated-SDK comparison from both before committing, since neither publishes pricing.
💰 Pricing
📊 Global score
🤖 AI-enriched data
Aucune tarification publique visible.
Pros
Génère les SDKs officiels d'OpenAI, Anthropic et Cloudflare — validation de qualité forte
Couvre SDKs, documentation, CLI et serveurs MCP depuis une seule spec OpenAPI
Support de nombreux langages (TypeScript, Python, Go, Java, Kotlin, Ruby, C#, PHP, Terraform)
Équipe rejointe par Anthropic en 2026 — priorité probable sur l'outillage agent-facing
Cons
Aucune tarification publique
Roadmap désormais liée aux priorités d'Anthropic post-rapprochement
Différenciation technique vs Fern à valider par une comparaison directe des SDKs générés