Directory / Stainless
Stainless
Verified
Typed SDK generation from OpenAPI specifications.
Stainless generates and maintains typed SDKs from an OpenAPI specification. The specification is the contract and the output is code. Factories use it so agents and humans do not hand-write client libraries.
- Model support
- Multi-model
- Deployment
- Cloud
- Open source
- No
- License
- Proprietary
- Pricing model
- Enterprise
- Added / updated
- 19 Aug 2026 / 19 Aug 2026
Assessment
Stainless is a deterministic generator for typed clients from OpenAPI specifications. Generated clients avoid hand-written SDK work; the product remains a narrow enterprise tool. Fern is the closest comparison.
Strengths
- OpenAPI as the source of truth.
- Generated clients beat improvised agent code for public APIs.
- Fits API-first companies.
Limitations
- Narrow SDK-generation job; no general agent.
- Generated quality depends on a complete, consistent specification.