trpc-fullstack

# tRPC Full-Stack ## Overview tRPC lets you build fully type-safe APIs without writing a schema or code-generation step. Your TypeScript types flow from the server router directly to the client — so every API call is autocompleted, validated at compile time, and refactoring-safe. Use this skill when building TypeScript monorepos, Next.js apps, or any project where the server and client share a codebase. ## When to Use This Skill - Use when building a TypeScript full-stack app (Next.js, Remix, Express + React) where the client and server share a single repo - Use when you want end-to-end type safety on API calls without REST/GraphQL schema overhead - Use when adding real-time features (subscriptions) to an existing tRPC setup - Use when designing multi-step middleware (auth, rate limiting, tenant scoping) on tRPC procedures - Use when migrating an existing REST/GraphQL API to tRPC incrementally ## Core Concepts ### Routers and Procedures A **router** groups related **procedures** (think: endpoints). Procedures are typed functions — `query` for reads, `mutation` for writes, `subscription` for real-time streams. ### Input Validation with Zod All procedure inputs are validated with Zod schemas. The validated, typed input is available in the procedure handler — no manual parsing. ### Context `context` is shared state passed to every procedure — auth session, database client, request headers, etc. It is built once per request in a context factory. **Important:** Next.js ...