Stainless
Stainless is an API developer experience platform that generates best-in-class SDKs, interactive documentation, production-ready CLI tools, MCP servers, and Terraform providers directly from an OpenAPI specification. Trusted by Anthropic, Cloudflare, Google, and OpenAI, Stainless automates the boilerplate of client library development including HTTP requests, retries with exponential backoff, streaming, and pagination. The platform supports TypeScript, Python, Go, Java, Kotlin, Ruby, C#, PHP, and Terraform, with Rust and Swift in development.
Stainless publishes 12 API contracts indexed on the APIs.io network, including Build Target Outputs API, Builds API, Orgs API, and 9 more. Tagged areas include Code Generation, Documentation, Developer Experience, MCP, and Platform.
The Stainless catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.
Stainless’ developer surface includes CLI, support, API reference, getting-started guide, authentication, developer portal, documentation, and 34 more developer resources.
What this lets a business do 1
Business capabilities this provider's published APIs can perform, derived from its own contracts. Browse all capabilities →
Kin Score
What adopting Stainless moves on the Kin Score 11
Stainless is an area vendor: providers adopt it to run part of their developer surface. This is the Kin Score checks its features can move for a provider that adopts it, what each one really earns, and what it earns nothing for.
Stainless reaches the most Developer Ergonomics surface of the SDK generators: SDKs in eight or more languages, a generated CLI, and a static, server-light docs platform with an API reference, per-page Markdown and an llms.txt. Each counts once the provider declares it. Its MCP servers expose the same two Code Mode tools for every customer, so they score as platform (0.25 of 12). Its generated SKILL.md files are the derived class (0.25). The decorated OpenAPI adds SDK snippets, not request/response examples, and is not an Overlay document, so neither examples_present nor overlay_published moves. Unless the provider uses the docs platform or a default-hosted MCP server, Stainless output looks like the provider’s own work.
| Check | Earns | Through |
|---|---|---|
| MCP Serverplatform Agent ReadinessCode Mode exposes the same two tools (docs search, execute code) for every Stainless customer. That shared tool shape is what 0.22.0 grades platform (0.25). There is a fair argument that the SDK behind the executor is the provider’s own. It belongs in the… |
3.0 of 12 | MCP server generation (Code Mode) |
| Request/Response Examplespartial Agent ReadinessThe added snippets are SDK calls, not request/response examples. The dimension reads examples first, so Stainless reaches only the Code Samples link fallback (0.25). |
1.8 of 7 | Decorated OpenAPI with SDK code samples |
| Agent Skillsdiscounted Agent ReadinessGenerated from the spec rather than written by the provider, so the derived class. |
1.3 of 5 | Generated SKILL.md for the customer's API |
| Three or more SDKs Developer ErgonomicsPublish three or more language SDKs and declare each as its own SDK entry. |
4.0 of 4 | SDK generation |
| Documentationsaturated Developer Ergonomics95% of providers with a contract, docs and a reference already earn this; the vendor cannot move it for most of its buyers. |
4.0 of 4 | Stainless Docs Platform |
| Publishes llms.txt DiscoverabilityThe file is added by the provider from its own docs content on its own domain, which format rule 2 credits in full. |
4.0 of 4 | Per-page Markdown and llms.txt |
| Published example corpus Contract QualityDeclare the page or repository carrying the generated snippets as a CodeSamples entry. |
4.0 of 4 | Decorated OpenAPI with SDK code samples |
| At least one SDK Developer ErgonomicsPublish a generated SDK and declare it as an SDK entry in apis.yml. |
3.0 of 3 | SDK generation |
| Command-line interface Developer ErgonomicsRelease the generated CLI and declare it as a CLI entry. |
3.0 of 3 | CLI generation |
| API referencesaturated Developer Ergonomics94% of providers with a contract, docs and a reference already earn this; the vendor cannot move it for most of its buyers. |
3.0 of 3 | Stainless Docs Platform |
| Agent Skilldiscounted Developer ErgonomicsDeclare the published skill as an AgentSkill entry. |
0.8 of 3 | Generated SKILL.md for the customer's API |
What Stainless ships that earns nothing (4)
- Decorated OpenAPI with SDK code samples — x-codeSamples and x-stainless-snippets are SDK snippets. The check counts request or response examples.
- Decorated OpenAPI with SDK code samples — The decorated spec is a full copy of the OpenAPI with snippets added, not an OpenAPI Overlay document.
- Stainless CLI skill (stl skills) — The stl skill teaches an agent to drive Stainless and says nothing about the customer’s API.
- SDK generation — SDK retries do not add an idempotency key to the contract, and the dimension reads the contract.
A model, not a score. Adopting this vendor changes a provider's Kin Score only when the provider publishes the resulting artifacts on its own surface; nothing here writes a score, and no sponsorship or partnership can. The rating is not for sale → · Full vendor facets artifact
Standards implemented 2
Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.
APIs 12
Individual APIs this provider publishes, each with its own machine-readable definition.
Stainless SDK Generator
Generate production-ready SDKs in TypeScript, Python, Go, Java, Kotlin, Ruby, C#, PHP, and Terraform from an OpenAPI specification. Stainless handles HTTP requests, retries with...
Stainless Docs Platform
The Stainless Docs Platform combines your API reference, usage examples, and narrative guides into a single, cohesive experience that evolves with your API. Go from an OpenAPI s...
Stainless MCP Servers
Stainless generates production-ready MCP (Model Context Protocol) servers optimized for agentic coding and context limits directly from an OpenAPI spec. Production-grade capabil...
Stainless CLI
The Stainless CLI generates production-ready command-line interfaces from an OpenAPI specification. Generated CLIs provide a consistent, typed interface for interacting with any...
Stainless Terraform Providers
Stainless generates production-ready Terraform providers from an OpenAPI specification, enabling infrastructure-as-code access to any REST API without manual Terraform provider ...
Stainless Build Target Outputs API
The Build Target Outputs API from Stainless — 1 operation(s) for build target outputs.
Stainless Builds API
The Builds API from Stainless — 4 operation(s) for builds.
Stainless Orgs API
The Orgs API from Stainless — 2 operation(s) for orgs.
Stainless Projects API
The Projects API from Stainless — 9 operation(s) for projects.
Stainless User API
The User API from Stainless — 1 operation(s) for user.
Stainless Spec API
The Spec API from Stainless — 1 operation(s) for spec.
Stainless Open API
The Open API API from Stainless — 1 operation(s) for open api.
Scroll for all 12
Open Collections 6
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
Stainless Platform Build Target Outputs API
OPEN COLLECTIONStainless Platform Build Target Outputs Builds API
OPEN COLLECTIONStainless Platform Build Target Outputs Orgs API
OPEN COLLECTIONStainless Platform Build Target Outputs Projects API
OPEN COLLECTIONStainless Platform Build Target Outputs User API
OPEN COLLECTIONStainless Platform API
OPEN COLLECTIONAgent Skills 2
Packaged agent skills for driving this provider's APIs from an AI assistant.
stainless-builds-diagnostics
AGENT SKILLstainless-create-and-list-projects
AGENT SKILLStainless API pricing
Prices published by Stainless, read 2026-10-28 from www.stainless.com/pricing/.
| Plan | Price |
|---|---|
| Free | $0 Includes: Up to 5 generators; 5 seats; ≤25 endpoints incl.; preview builds in CI 100/mo free |
| Starter | Starter |
| Pro | Pro |
| Enterprise | Enterprise |
Plan details, limits and sources →
Rate limits
- Free Tier Default: 10 requests per minute
- Free Tier Monthly Quota: 1000 requests per month
- Professional Tier Default: 100 requests per minute
Compiled by API Evangelist, not yet checked against Stainless's documentation. All 5 limits →
Billed by: generator · FinOps profile →
Pricing Plans 1
Published pricing tiers and plan structures.
Rate Limits 1
Documented rate limits and quota policies.
Stainless Rate Limits
RATE LIMITSFinOps 1
Cost, billing, and metering signals for API financial operations.
Stainless Finops
FINOPSSemantic Vocabularies 1
JSON-LD contexts and semantic vocabularies used across these APIs.
Stainless Context
JSON-LDSpectral Rules 1
Spectral governance rulesets for linting and validating these APIs. Counts are the severity each rule declares, not results of running them.
Stainless API Rules
SPECTRALOpenAPI Overlays 1
Overlays applied on top of this provider's contracts. Each card says who wrote it: a document the provider publishes, or one API Evangelist derived or generated.
Stainless Openapi Overlay
DERIVEDJSON Schema 9
Standalone JSON Schema definitions for this provider's data models.
BuildDiagnostic
JSON SCHEMABuild
JSON SCHEMAFileInput
JSON SCHEMAOrg
JSON SCHEMAProjectBranchMinimal
JSON SCHEMAProjectBranch
JSON SCHEMAProject
JSON SCHEMATarget
JSON SCHEMAUser
JSON SCHEMAScroll for all 9
Examples 1
Example request and response payloads for these APIs.
Security Posture 3
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access (API Evangelist recommendations) 1
Recommended x-agentic-access execution contracts for AI agents.
Resources
Get Started 3
Portal, sign-up, and the first successful call
Documentation 3
Reference material describing how the API behaves
Agent Surfaces 4
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 6
Pagination, idempotency, versioning, errors, and events
Build 2
SDKs, sample code, and the tooling you integrate with
Access & Security 7
Authentication, authorization, and security posture
Scroll for all 7
Operate 3
Status, limits, changes, and where to get help
Commercial 4
Pricing, plans, and the legal terms of use
Company 4
The organization behind the API
Other 5
Properties that don't map to a standard resource type
Source (apis.yml)
Stainless API — frequently asked questions
Does Stainless have an API?
Yes. APIs.io lists 12 APIs from Stainless, including Stainless SDK Generator, Stainless Docs Platform and Stainless MCP Servers, and 9 more.
Is there an OpenAPI specification for the Stainless API?
Yes. APIs.io indexes 7 OpenAPI specifications for Stainless, each linked for download from this page.
How do I authenticate with the Stainless API?
Stainless uses bearer-token authentication (http · 1 scheme). The details are profiled on APIs.io as Stainless Authentication.
How much does the Stainless API cost?
Stainless publishes its prices; its Free plan is $0 as of 2026-10-28. APIs.io lists 4 pricing plans for Stainless, with each plan's price, limits and inclusions under Pricing on this page.
Is the Stainless API ready for AI agents?
Stainless has a Kin Score of 53.6 out of 100 (developing) and an Agent Readiness score of 23.2 (agent-aware), scored by API Evangelist on 2026-11-13.
Work with this as data
Every provider here is available over the APIs.io API and to AI agents over MCP.