Nestia
A set of helper libraries for NestJS that generate fast runtime validators, a typed client SDK with a mockup backend simulator, automatic Swagger docs and end-to-end test functions from pure TypeScript types, plus an LLM function-calling library.
Nestia is a collection of libraries that extend NestJS. Its core package provides decorators and WebSocket route helpers with a runtime validator the project reports as tens of thousands of times faster than class-validator and JSON serialization reported as hundreds of times faster than class-transformer, derived directly from a project's existing TypeScript types rather than separate schema definitions.
Its SDK generator produces a typed client library of fetch functions matching the server's routes, similar in spirit to tRPC, along with a mockup simulator that acts as an embedded backend for the client during development, comparable to a fully automated version of msw, and automatic end-to-end test function generation. A companion Swagger generator and an online TypeScript editor round out the API documentation side, while a separate agentic AI library, Agentica, adds LLM function-calling on top of the same typed definitions, and a vibe-coding agent called AutoBE can generate a NestJS application from a description.
It is written in TypeScript and released under the MIT license.