Edge Deployment with Bun

🚀 Introduction to Edge Deployment with Bun

The modern web demands speed, proximity, and scalability — and that’s where edge deployment shines. Pairing the lightning-fast Bun runtime with edge platforms like Cloudflare Workers, Vercel Edge Functions, and Deno Deploy gives developers a killer combo for ultra-low latency applications.

In this tutorial, we’ll explore how to deploy Bun-based code to the edge, best practices, and tools to make it happen.

🌐 What Is Edge Deployment?

Edge deployment is the process of running your application closer to the end user by utilizing geographically distributed data centers (aka edge locations).

This reduces latency and improves performance significantly, especially for APIs, content delivery, and interactive apps.

âš¡ Why Use Bun at the Edge?

• âš¡ Ultra-fast startup time and low memory usage
• 📦 Zero-config TypeScript support
• 🛠️ Native ESM, no transpilation needed
• 🔥 Fast HTTP server, ideal for lightweight edge APIs

🧪 Option 1: Bun + Hono on Cloudflare Workers

While Bun isn’t natively supported on Cloudflare Workers, frameworks like Hono offer Bun-style routing and are compatible with edge runtimes.

Here's how to run a Bun-like experience at the edge:

// src/index.ts
import { Hono } from 'hono'

const app = new Hono()

app.get('/', (c) => c.text('âš¡ Hello from Bun at the edge!'))

export default app

Use Wrangler to deploy:

# wrangler.toml
name = "bun-edge-app"
compatibility_date = "2024-06-01"

Deploy with:

npx wrangler deploy

🏁 Option 2: Bun Logic in Vercel Edge Functions

Vercel doesn’t directly support Bun but allows TypeScript-based edge functions that emulate Bun’s structure.

Here’s a working edge function:

// /api/edge.ts
export const config = {
  runtime: 'edge'
}

export default async function handler(request: Request) {
  return new Response("🌍 Edge response with Bun-style code")
}

Keep dependencies minimal and make sure to avoid Node.js-specific APIs in your Bun code when targeting Vercel Edge.

📦 Deploying Bun with Deno Deploy

Since Deno Deploy supports TypeScript and ESM out of the box, it's a great place to port Bun projects by stripping Node-specific features.

You can build your app with Bun and then serve it in Deno:

// index.ts
import { serve } from "https://deno.land/std/http/server.ts"

serve(() => new Response("🦕 Bun logic running in Deno Deploy!"))

Deploy using deno deploy --project=my-bun-edge-app.

🐳 Bun + Docker on Fly.io Edge

Fly.io allows you to deploy Dockerized Bun apps close to users globally.

Create a Dockerfile like this:

# Dockerfile
FROM oven/bun

WORKDIR /app
COPY . .
RUN bun install
CMD ["bun", "index.ts"]

Configure with fly.toml:

# fly.toml
app = "bun-edge-app"

[env]
PORT = "3000"

[[services]]
  internal_port = 3000
  protocol = "tcp"
  [[services.ports]]
    handlers = ["http"]
    port = 80

Then launch and deploy:

fly launch
fly deploy

🧠 Best Practices for Edge-ready Bun Apps

• ⚖️ Keep your logic stateless — avoid local file reads or in-memory caching
• 🎯 Use minimal, fast dependencies compatible with edge runtimes
• 🛡️ Handle CORS and security headers properly
• 🧩 Split heavy logic or DB interactions to background APIs

🧰 Sample Edge-Friendly Bun Project Structure

bun-edge-app/
├── src/
│   └── index.ts
├── public/
├── fly.toml or wrangler.toml
├── Dockerfile
├── bun.lockb
└── package.json

✅ Conclusion: Is Bun Ready for the Edge?

Absolutely. While Bun is still evolving in terms of native support on serverless edge platforms, using Docker, ESM-compatible libraries, and smart routing frameworks like Hono makes edge deployment fast, easy, and scalable. You get Bun’s performance plus the global reach of edge platforms. Win-win. 🌍⚡

Start with Cloudflare Workers, Vercel Edge, or Fly.io today — and let Bun turbocharge your edge-powered projects!

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