DevOps Coach

Jan 8, 2026 · Backend Development

How a 300‑Line Go PDF Invoice API Generates $2K/Month with Zero Overhead

This article explains how a compact Go‑based PDF invoice generator for freelancers, built as a single‑binary API, evolved from a weekend prototype to a steady side‑business earning $1,500‑$2,000 monthly, detailing its architecture, performance gains, low‑cost hosting, and monetization model.