> For the complete documentation index, see [llms.txt](/llms.txt) # Glotto — SDKs, docs, and MCP from one API spec **Spec → SDKs · Docs · MCP** **Spec in. Best-in-class SDKs, docs, and an MCP server — out.** Glotto keeps your entire developer surface — idiomatic SDKs in 13 languages (mobile-first), a docs site you own, and a multi-mode MCP server — provably correct and in lockstep with your spec, forever. The authored input is `petstore.openapi.yaml`: `operationId: listPets` names the call, and `nextCursorPath: next_cursor` tells the generated paginator where to find its next cursor. ## Built for what the others skip **The wedge** Where Stainless, Speakeasy, and Fern stop, Glotto keeps going. ### Machine-guaranteed correctness Every regeneration is compile-verified and contract-tested across each language, drift-gated, and preserves your custom code — provably in lockstep with your spec. ### Mobile-first SDKs A React Native / Expo spearhead plus Kotlin Multiplatform and native Android/iOS — the mobile targets no rival ships first-class. ### Deploy on your terms Self-host or single-tenant, with managed release PRs across GitHub, GitLab, and Bitbucket — not a GitHub-cloud-only box. ## Three things, from one spec **The output** Every push regenerates all three, in lockstep with your API. ### SDKs 13 languages, mobile-first, with a hand-crafted feel and machine-guaranteed correctness — not generated boilerplate. ### Docs A standalone Astro docs site you own — multi-language snippets, search, and an MCP-ready index. ### MCP server Dual-mode (Code Mode + per-operation) so AI agents can drive your API safely. ## Push a spec. Merge to publish. Then keep being right. **How it works** Five steps take your spec to published SDKs. The sixth is the one that matters: every push after the first re-runs the whole pipeline, proves the result still compiles and still honours your contract in every language, and preserves the code you wrote by hand. 1. **API spec** — Point Glotto at an OpenAPI, AsyncAPI, or GraphQL document — a file, a URL, a git ref in another repo, or your own exporter command. 2. **Glotto IR** — Your spec normalizes to one canonical, byte-stable intermediate representation, so every language generates from the same reading of your API rather than from its own. 3. **Codegen** — Every declared target emits at once — SDKs across 13 languages, your docs site, and the MCP server — from that single IR. 4. **Verify** — Before anything opens, each SDK is compiled in its own real toolchain and run against a shared contract suite, so "it generated" and "it works" are not the same claim. 5. **Release PR** — A reviewable pull request lands on GitHub, GitLab, or Bitbucket — your repos, your review, your history. Nothing is force-pushed and nothing publishes itself. 6. **Every push after** — The loop. Regeneration is drift-gated against the committed output, your hand-written code survives via a three-way merge, and a breaking change is reported before it ships, not after. ## Migrating from Stainless? **Switching costs, near zero** Stainless is winding down its hosted platform. Glotto picks up where it leaves off — a superset of its SDK languages, the same Astro docs approach, and a multi-mode MCP server including Code Mode and dynamic tools. One command converts your `stainless.yml`. - [Read the migration guide →](/docs/migrate-from-stainless) ## Ship the SDKs your users deserve. One spec. 13 languages. Docs and MCP included. - [Get started](/docs/getting-started) - [Read the docs](/docs) ## Auto-paginated, typed, retried — in the idiom of each language. This page renders emitted samples for every supported language. They are reproduced in full — emitted bytes, not hand-written prose — on [pagination](/docs/pagination/). ## What Codegen emits — authentication, in every language This page renders emitted samples for every supported language. They are reproduced in full — emitted bytes, not hand-written prose — on [authentication](/docs/authentication/). ## What Verify catches — drift between your spec and the committed SDK This page renders one artifact Glotto's own machinery emitted — one word changed in the spec — `summary: List pets` became `summary: List every pet`. It was emitted by renderDriftReport (@glotto/core-vcs) over packages/cli/tests/fixtures/drift-gate (files compared 81, out of sync 11), and is reproduced in full — real output, not hand-written prose — on [drift-detection](/docs/drift-detection/). ## Sections - [Documentation](/docs/): Configuration reference, generated SDK guides, and the glotto.yml schema. - [Changelog](/changelog/): Customer-facing changes to the generated SDKs, docs, and MCP server. - [Engineering blog](/blog/): How the correctness engine is built, and what we learned building it.