Building a Clojure/Datomic SaaS from Scratch

A hands-on, chapter-by-chapter guide to building a production-grade SaaS application in Clojure and Datomic — from a reproducible development environment all the way to automated CI/CD deployment.

Each chapter is self-contained but builds on the last. Use the sidebar to navigate, or the arrow keys to move between chapters. Press s or click the magnifier to search the full text.

What's covered

• A reproducible devcontainer dev environment (Docker, Caddy, Mailpit, TLS)
• Strict compilation to catch reflection and boxed math early
• A web server with Ring, http-kit, and Reitit
• Live reload, DOM-morphing hot reload, and a Hiccup source inspector
• Datomic schema and queries, i18n, and Tailwind styling
• Server-rendered views with Hiccup and E2E testing with Playwright
• Passwordless auth with single-use, HMAC-signed magic links
• An admin dashboard, a hardened asset pipeline (hashing, SRI, CSP), Lighthouse audits, and CI/CD

Start with the primer for what we are building and why, or jump to any topic from the table of contents.