The latest articles on DEV Community by Mooktakim Ahmed (@mooktakim). https://dev.to/mooktakim https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F402496%2Fd296bd07-5077-4030-b2d5-b7310dc114eb.jpg https://dev.to/mooktakim en Mooktakim Ahmed Tue, 31 Mar 2026 14:01:59 +0000 https://dev.to/mooktakim/building-multi-tenant-saas-with-rails-8-caddy-and-kamal-2fcn https://dev.to/mooktakim/building-multi-tenant-saas-with-rails-8-caddy-and-kamal-2fcn <p>After publishing the Kamal deployment guide, the most common question was: "How do I handle multiple tenant domains with automatic SSL?"</p> <p>kamal-proxy can't do it — every new domain means editing <code>deploy.yml</code> and redeploying. So I wrote a guide that solves it end-to-end.</p> <p><strong>What it covers:</strong></p> <ul> <li>Why kamal-proxy's SSL doesn't scale for multi-tenant apps</li> <li>Running Caddy as a Kamal accessory for on-demand TLS</li> <li>The <code>/internal/tls/verify</code> endpoint — Caddy asks Rails before issuing any cert</li> <li>Subdomain data model, validation, and auto-generation</li> <li>Constraint-based routing (<code>TenantConstraint</code> / <code>MainConstraint</code>)</li> <li>Resolving the current tenant from the request hostname</li> <li>Custom domain model with DNS instructions for users</li> <li>Full <code>Caddyfile</code> and <code>deploy.yml</code> configuration</li> <li>Why <code>config.hosts.clear</code> is safe when Caddy gates traffic</li> </ul> <p>The architecture is based on a real production app (<a href="https://dinehere.ai" rel="noopener noreferrer">Dinehere</a> — AI restaurant website builder) where each tenant gets a subdomain and can connect their own domain.</p> <p>This is Part 2 of the series. Part 1: <a href="https://mooktakim.com/blog/deploying-rails-with-kamal/" rel="noopener noreferrer">The Complete Guide to Deploying Rails 8 with Kamal on Hetzner</a></p> ruby rails saas devops Mooktakim Ahmed Wed, 25 Mar 2026 22:27:56 +0000 https://dev.to/mooktakim/the-complete-guide-to-deploying-rails-8-with-kamal-on-hetzner-586e https://dev.to/mooktakim/the-complete-guide-to-deploying-rails-8-with-kamal-on-hetzner-586e <p>I wrote the end-to-end deployment guide I wish existed when I first set up Rails 8 with Kamal.</p> <p>Most tutorials cover bits and pieces - here's one that covers everything from a bare server to production.</p> <h2> What it covers </h2> <ul> <li>Ordering and provisioning a Hetzner dedicated server</li> <li>Ansible provisioning with <a href="https://github.com/guillaumebriday/kamal-ansible-manager" rel="noopener noreferrer">kamal-ansible-manager</a> </li> <li>The production Dockerfile (jemalloc, Thruster, multi-stage build)</li> <li>Kamal <code>deploy.yml</code> — every section explained</li> <li>The full Solid stack: Solid Queue, Solid Cache, Solid Cable with 4 separate SQLite databases</li> <li>ActiveStorage in proxy mode for Cloudflare caching</li> <li>First deploy with <code>kamal setup</code> </li> <li>Cloudflare DNS, SSL (Full mode), and CDN caching</li> <li>Hetzner Storage Box for off-server backups via Samba/CIFS</li> <li>Netdata for server monitoring</li> <li>Litestream for continuous SQLite replication</li> <li>docker-volume-backup for daily storage snapshots</li> </ul> <h2> The stack </h2> <p>No Postgres. No Redis. No PaaS. Everything runs on a single server for ~36 EUR/month.</p> <p>Client → Cloudflare → kamal-proxy → Thruster → Puma → Rails 8</p> <p><strong>Read the full guide here:</strong> <a href="https://mooktakim.com/blog/deploying-rails-with-kamal/" rel="noopener noreferrer">The Complete Guide to Deploying Rails 8 with Kamal on<br> Hetzner</a></p> <p>Happy to answer any questions in the comments.</p> rails ruby docker kamal