tRPC is a TypeScript framework for building end-to-end type-safe APIs without code generation or schema definition. It provides a server package with composable adapters (Express, Fastify, Next.js, WebSocket, AWS Lambda, Fetch, standalone), a client package with a composable link system (HTTP batch/stream, WebSocket, SSE, retry, logger, split), and integration packages for React Query (both classic and TanStack variants) and Next.js (Pages and App Router). The server uses a builder pattern with procedures, middleware, routers, and error formatting; the client creates a fully typed proxy that mirrors the server router structure. tRPC also supports data transformers (SuperJSON, etc.), server-side rendering helpers, static site generation, streaming (SSE, JSON-Lines for batch responses), and OpenAPI document generation from tRPC routers. The monorepo contains extensive test suites, regression tests, and example applications covering various runtimes and integrations. Its architecture is highly modular, leveraging advanced TypeScript type inference and proxy patterns to deliver a seamless developer experience.