Blog ·

Introducing OpenWorkers

Self-hosted Cloudflare Workers in Rust.

OpenWorkers is an open-source runtime for executing JavaScript in V8 isolates. It brings the Cloudflare Workers programming model to your own infrastructure.

What works today

export default {
  async fetch(request, env) {
    const data = await env.KV.get("key");
    const rows = await env.DB.query(
      "SELECT * FROM users WHERE id = $1",
      [1]
    );
    return Response.json({ data, rows });
  }
};

Features

Bindings

  • KV storage (get, put, delete, list)
  • PostgreSQL database
  • S3/R2-compatible storage
  • Service bindings
  • Environment variables & secrets

Web APIs

  • fetch, Request, Response
  • ReadableStream
  • crypto.subtle
  • TextEncoder/Decoder, Blob
  • setTimeout, AbortController

Architecture

                         ┌─────────────────┐
                         │  nginx (proxy)  │
                         └────────┬────────┘
                                  │
         ┌───────────────┬────────┴──┬───────────────┐
         │               │           │               │
         │               │           │               │
┌────────┸────────┐ ┌────┸────┐ ┌────┸────┐ ┌────────┸────────┐
│   dashboard     │ │  api    │ │ logs *  │ │  runner (x3) *  │
└─────────────────┘ └────┬────┘ └────┰────┘ └────────┰────────┘
                         │           │               │
                         │           │               │
                ┌────────┸────────┐  │      ┌────────┸────────┐
                │   postgate *    │  └──────┥      nats       │
                └─────────────────┘         └────────┰────────┘
                                                     │
                                                     │
                ┌─────────────────┐           ┌──────┴───────┐
         * ─────┥   PostgreSQL    │           │ scheduler *  │
                └─────────────────┘           └──────────────┘
  • V8 Isolates: Sandboxing with CPU (100ms) and memory (128MB) limits per worker.
  • Cron Scheduling: Built-in support for 5 or 6-field cron syntax.
  • Compatibility: Cloudflare Workers syntax compatible.

Self-hosting

Deployment is designed to be simple. A single PostgreSQL database and a single Docker Compose file is all you need.

git clone https://github.com/openworkers/openworkers-infra
cd openworkers-infra && cp .env.example .env
docker compose up -d postgres
# Run migrations, generate token
docker compose up -d

Why I built this

This project has been evolving for about 7 years. I started experimenting with vm2 for sandboxing JS, then Cloudflare launched Workers and I got hooked on the model. When Deno came out, I switched to deno-core and ran on that for two years. Recently, with Claude’s help, I rewrote everything on top of rusty_v8 directly.

The goal has always been the same: run JavaScript on your own servers, with the same DX as Cloudflare Workers but without vendor lock-in.

  • Your Data - Never leaves your infrastructure
  • Predictable Costs - No per-request pricing
  • No Lock-in - Cloudflare Workers compatible

Next up: Execution recording & replay for deterministic debugging.

GitHub | Docs | Self-hosting Guide