Cloudflare Worker Integration

What It Is

Experimental Cloudflare Worker adapter for Elysia.

Setup

Install Wrangler:

wrangler init elysia-on-cloudflare

Apply adapter + compile:

import { Elysia } from 'elysia'
import { CloudflareAdapter } from 'elysia/adapter/cloudflare-worker'

export default new Elysia({
  adapter: CloudflareAdapter
})
  .get('/', () => 'Hello Cloudflare Worker!')
  .compile()  // Required

Set compatibility date (min 2025-06-01):

// wrangler.json
{
  "name": "elysia-on-cloudflare",
  "main": "src/index.ts",
  "compatibility_date": "2025-06-01"
}

Dev server:

wrangler dev
# http://localhost:8787

No nodejs_compat flag needed.

Limitations

Elysia.file + Static Plugin don't work (no fs module)
OpenAPI Type Gen doesn't work (no fs module)
Cannot define Response before server start
Cannot inline values:

// ❌ Throws error
.get('/', 'Hello Elysia')

// ✅ Works
.get('/', () => 'Hello Elysia')

Static Files

Use Cloudflare's built-in static serving:

// wrangler.json
{
  "assets": { "directory": "public" }
}

Structure:

├─ public
│  ├─ kyuukurarin.mp4
│  └─ static/mika.webp

Access:

http://localhost:8787/kyuukurarin.mp4
http://localhost:8787/static/mika.webp

Binding

Import env from cloudflare:workers:

import { env } from 'cloudflare:workers'

export default new Elysia({ adapter: CloudflareAdapter })
  .get('/', () => `Hello ${await env.KV.get('my-key')}`)
  .compile()

AoT Compilation

As of Elysia 1.4.7, AoT works with Cloudflare Worker. Drop aot: false flag.

Cloudflare now supports Function compilation during startup.

pnpm

Manual install:

pnpm add @sinclair/typebox openapi-types

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