Documentation

Everything you need to plug your SaaS into Letter: report users and events from your backend, then drive onboarding sequences off of them.

Getting started

Agent setup Hand this to your coding agent: install, authenticate, instrument in one pass Read → Initial import Bulk-load existing users and accounts from your SaaS in one shot Read →

API

Ingestion API identify · group · track · batch · auth · rate limits Read →

SDKs

SDKs Official server-side clients for Node, Python, and Ruby. Same ingestion API, idiomatic in each language, with batching, retries, and idempotency built in. Read → Node SDK Auto-batching client for Node.js with retries and idempotency Read → Python SDK Auto-batching client for Python with retries and idempotency Read → Ruby SDK Auto-batching client for Ruby with retries and idempotency Read →