API-first development, contract before code, versioned without breaking partners.
The API isn't a side door to your product, for an API-first SaaS, the API is the product. We design the contract first, generate typed clients from it, version it so partners don't churn on a renamed field, and treat the docs as a real surface, not a wiki page.
What we build
OpenAPI as the source of truth
We write the OpenAPI spec before the handlers, not after. The spec drives the typed server, the client SDK, the docs site, and the test suite. Renaming a field in the spec propagates everywhere; you don't end up with drift between what the docs say and what the API does.
Typed clients in every language you ship
Generated TypeScript, Swift, and Python clients from the same spec. Your customers and your internal teams use the same shapes. A field that's required in the spec is required in the IDE; nullable is nullable; enums are enums.
Versioning that doesn't burn partners
Breaking changes go behind a new version. Additive changes (new fields, new endpoints) stay on the current version. We publish a deprecation calendar, send notices to integration partners, and keep prior versions running for the documented window.
Rate limits, idempotency, and pagination as defaults
Every write endpoint accepts an idempotency key. Every list endpoint paginates with cursors. Every API key gets a documented rate limit. Production-grade defaults; partners don't discover them by breaking their integration in week three.
Docs that engineers actually read
Generated docs from the spec, with runnable examples in each client language, real-shaped sample payloads, and an embedded API playground. Stripe-style developer experience, not a static reference that's six months stale.
Webhooks that survive the partner's downtime
Signed webhook payloads, exponential-backoff retries, and a replay endpoint for the inevitable partner-side outage. Failed deliveries don't disappear; partners can fetch the events they missed.
Where this fits
You're shipping a product that other developers will integrate against, and the API can't be an afterthought of your internal data model.
You have partner integrations and every release cycle breaks at least one of them because there's no versioning discipline.
Your docs site is a wiki page that nobody trusts because it's always behind what the API actually does.
Tech stack
- TypeScript
- OpenAPI
- tRPC
- Elysia
- Drizzle
Want this for your team?
30 minutes with a founder or senior engineer. We'll scope what you need and tell you straight whether Stacklane fits.
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