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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
Key features
- 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.
