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Hedystia is designed for developers who are tired of the friction between backend logic and frontend consumption. By making your route definitions the "ultimate source of truth," Hedystia automates the most tedious parts of API development.
It features a unique "Built-in Route Testing" framework where you define your tests right next to your logic, ensuring your API works as expected without complex integration suites. With @hedystia/client, your frontend gets a fully-typed HTTP client automatically, removing the "validation gap" forever.
Hedystia is a TypeScript framework that lets you build type-safe APIs with built-in validation, real-time subscriptions and automatic client generation.
- for
- TypeScript developers building backend APIs who want end-to-end type safety.
- pricing
- open source
- license
- MIT
works withTypeScriptBunWebSockets@hedystia/client
Key features
6 features of Hedystia
- Unified Inference — Server schemas are mirrored to the client, providing fully typed requests and responses.
- Built-in Validation — Route schemas act as runtime validators without external parsers.
- Real-Time First — WebSocket and SSE subscriptions are defined like HTTP endpoints with type safety.
- Auto Client Generation — @hedystia/client creates a fully typed HTTP client from server definitions.
- Bun Optimized — Runs natively on Bun for fast cold starts and minimal overhead.
- Auto Swagger Docs — Typing directly generates an OpenAPI spec via a plugin for interactive docs.
Use cases
- Create a CRUD API with type-checked request bodies and responses.
- Add real-time data streams (WebSocket/SSE) with the same type safety as HTTP routes.
- Generate a typed client library for a frontend app without manual code generation.
Hedystia vs alternatives
.png?width=64) Hedystia |  Hono |  FastAPI |  Remix |  Next.js | |
|---|---|---|---|---|---|
| Best for | End-to-end type-safe API development | Small, fast web APIs | Python APIs with type hints | Full-stack React web apps | React SSR and static sites |
| Pricing | Open source | Free | Free | Free | Free |
| DevHunt upvotes | 2 | 0 | 0 | 0 | 0 |
| Launched | Oct 2026 | — | — | — | — |
- Hedystia vs Hono: Hono is a minimal web framework for any JS runtime, lacking built-in type-safe schemas and auto client generation.
- Hedystia vs FastAPI: FastAPI provides Python-based type-hinted APIs but does not offer automatic TypeScript client generation.
- Hedystia vs Remix: Remix focuses on full-stack React apps and web standards, not on end-to-end TypeScript API safety.
- Hedystia vs Next.js: Next.js is a React framework for server-rendered pages, not a TypeScript-first API framework with built-in validation.
Hedystia FAQ
How does Hedystia ensure type safety between server and client?+
Route schemas drive TypeScript inference, so the same types are exported to the client via @hedystia/client.
Do I need external validation libraries?+
No, Hedystia’s built-in schema builder validates requests at runtime without external parsers.
Can I use Hedystia with frameworks other than Bun?+
It is designed for Bun but can run on any JavaScript runtime that supports the same APIs.
How are real-time subscriptions defined?+
Subscriptions are declared like HTTP endpoints and are delivered over WebSockets or SSE with type-safe streams.
Is documentation generated automatically?+
Yes, a plugin can generate OpenAPI/Swagger docs directly from the TypeScript types.
Summarized by DevHunt from docs.hedystia.com · Oct 6, 2026. Details may change; check the official site.
