How to Build a Multi-Tenant SaaS on Cloudflare Workers for \/usr/bin/bash/Month

Most SaaS tutorials end with a $50+/month hosting bill before you even have your first customer. Let's fix that. In this guide, I'll show you how to build a production-ready SaaS backend that costs $0/month to host — with auth, multi-tenancy, Stripe billing, and email. All running on Cloudflare Workers. The Stack Layer Technology Cost Runtime Cloudflare Workers Free (100K req/day) Framework Hono Free (npm) Database Cloudflare D1 (SQLite) Free (5M rows) Auth JWT via Web Crypto API Free Payments Stripe 2.9% + $0.30/txn Email Resend Free (100 emails/day) Total $0/month No AWS. No Vercel. No Docker. Just wrangler deploy . Architecture Overview ┌──────────────────────────────────────────┐ │ Cloudflare Workers │ │ │ │ ┌──────┐ ┌──────┐ ┌────────┐ │ │ │ Auth │ │ Orgs │ │Billing │ Hono │ │ │Routes│ │Routes│ │ Routes │ Router │ │ └──┬───┘ └──┬───┘ └───┬────┘ │ │ │ │ │ │ │ ┌──┴─────────┴───────────┴────┐ │ │ │ D1 (SQLite Database) │ │ │ └──────────────────────────────┘ │ │ │ │ External: Stripe A