CelsianJS

Backend framework built on Web Standard APIs. Multi-runtime server with plugin encapsulation, schema validation, type-safe RPC, background tasks, cron, and WebSocket support.

Install

npm install celsian

Or scaffold a new project:

npx create-celsian my-app
cd my-app
npm install
npm run dev

Quick Example

import { createApp, serve } from 'celsian'

const app = createApp()

app.get('/hello/:name', (req, reply) => {
  return reply.json({ message: `Hello, ${req.params.name}!` })
})

serve(app, { port: 3000 })

Features

• Plugin encapsulation -- Fastify-style scoped hooks and decorations. No accidental middleware leaks.
• Schema validation -- Auto-detects Zod, TypeBox, or Valibot. No config, no adapters.
• Type-safe RPC -- Define procedures with schemas, get end-to-end type safety via @celsian/rpc.
• Multi-runtime -- Runs on Node.js, Bun, Deno, Cloudflare Workers, AWS Lambda, Vercel.
• Background tasks -- Queue-based task processing with retries and timeouts.
• Cron jobs -- Schedule recurring tasks with cron expressions.
• WebSocket -- Built-in WebSocket support with broadcast and connection management.
• Security -- CORS, CSRF protection, Helmet-style headers, rate limiting, JWT auth.
• OpenAPI -- Auto-generated API documentation with Swagger UI.

What this package re-exports

celsian is a convenience meta-package. It re-exports @celsian/core and @celsian/schema only:

| Package | Re-exported here? | Contents | |---------|-------------------|----------| | @celsian/core | Yes, in full | Every export, including createApp, serve, cors, csrf, security, openapi, database, upload, createSSEHub, tasks and cron, WebSocket helpers, errors, logger, cookies, ETag, config | | @celsian/schema | Yes, in full | fromSchema, fromZod, fromTypeBox, fromValibot, coerceQueryParams, coerceString |

Both are re-exported with export *, so anything @celsian/core exports is reachable from celsian under the same name. Before 0.6.0 this was a hand-maintained list that had drifted to 33 of core's 65 exports, which is why upload and createSSEHub used to come back undefined here despite being documented in the core README.

Everything else is a separate install and is not available from celsian:

npm install @celsian/rpc          # type-safe RPC procedures
npm install @celsian/jwt          # JWT auth plugin
npm install @celsian/rate-limit   # rate limiting
npm install @celsian/cache        # response cache, session store
npm install @celsian/compress     # gzip/deflate
npm install -D @celsian/cli       # dev server, routes, build, deploy

// Correct: RPC comes from its own package.
import { createApp, serve } from 'celsian';
import { procedure, router, RPCHandler } from '@celsian/rpc';

Documentation

See the GitHub repository for full documentation:

• Quick Start
• Hooks Lifecycle
• Plugins and Encapsulation
• Deployment Guide

License

MIT