Backend·January 28, 2026·12 min read
Building Classio: A Serverless Deployment Platform
Classio is a lightweight, self-hosted alternative to Cloudflare Workers that lets you deploy serverless functions to your own infrastructure. Built with Bun, it demonstrates the core concepts of a serverless platform in under 1000 lines of code.
Introduction
System Architecture
API Server
Runtime Worker
CLI Tool
How Deployment Works
Each deployment is atomic—either everything succeeds or nothing changes.
What Could Be Better
Security Gaps
Scalability Bottlenecks
Developer Experience
Path to Production
Why This Matters
Conclusion
Filed under fieldnotesJanuary 28, 2026