Entra ID with Rails 8 and OmniAuth

Rails 8’s built-in authentication generator doesn’t support SSO itself, so the usual approach is to keep its session handling and add OmniAuth with the Entra ID strategy. After Entra verifies the person, you log them in through the same start_new_session_for that the generator created. ...

November 13, 2026 · 2 min · Markus Greiner

🤖 Integrate Swagger UI in Rails

You can add Swagger UI directly to app/views/layouts/application.html.erb using the CDN. No gem or npm package is required. The following uses the official Swagger UI distribution from unpkg and loads your Rails application’s OpenAPI specification. ...

November 7, 2026 · 2 min · Markus Greiner

Easily Host Multiple Rails Apps on One Machine with Caddy

Yes — very easily. Caddy is actually excellent for hosting multiple Rails apps on one machine. You simply: run each Rails app on a different internal port let Caddy route domains/subdomains to the correct app Example architecture Mac mini ├── Caddy ├── App 1 (Puma :3000) ├── App 2 (Puma :3001) ├── App 3 (Puma :3002) └── SQLite files Traffic: ...

November 3, 2026 · 2 min · Markus Greiner

Kamal on a Mac Mini

Kamal is built for Linux servers, so a Mac mini needs a few workarounds. It works because Kamal only needs SSH plus a working docker command on the target. Here’s the path: ...

November 3, 2026 · 3 min · Markus Greiner

Rails Engines

Rails engines An engine is a miniature Rails application that you plug into a host app. It can have its own models, controllers, views, routes, migrations, assets, and tests. In fact, a Rails app is an engine: Rails::Application inherits from Rails::Engine. That’s why everything you know about Rails carries over. ...

October 20, 2026 · 9 min · Markus Greiner

🤖 YARD Documentation in Ruby on Rails

🤖 YARD Documentation in Ruby on Rails YARD is the standard documentation tool for Ruby projects, including Rails apps. Here’s a quick rundown. ...

October 17, 2026 · 2 min · Markus Greiner

✨ Create Microsoft Action Items from Rails

🤖 How can I integrate Rails with Microsoft Graph Note: This was generated by ChatGPT ✨ Great — here’s a clean, production-ready Rails service object pattern for integrating your app with Microsoft Graph (for Outlook / Microsoft To Do / SharePoint). ...

February 12, 2026 · 3 min · Markus Greiner

Render deployment tips

Using private repository If you want to connect a private repository to render, proceed as follows: go to the Render Dashboard, on the top right click on + New and select Web Service you are redirected to a list with a tab Git Provider select Credentials (1) Under Select deployment credentials, pick you github repository Now do Configure in GitHub You are redirected to GitHub. _ Scroll down, until you see Repository Access Pick only select repositories, and pick the one you need. Voilà, you have now connected it to GitHub ...

February 12, 2026 · 3 min · Markus Greiner

🤖 OpenAI and Rails

🤖 Ruby on Rails integrated with OpenAI tool calling Below is a complete small Ruby on Rails example showing how to implement OpenAI tool calling end-to-end. ...

February 12, 2026 · 9 min · Markus Greiner

Rails app with Azure Entra-ID authentication

This post 1 demonstrates how to use Azure Entra-ID for authentication. According to What is Microsoft Entra ID?, Microsoft Entra ID is a cloud-based identity and access management service that your employees can use to access external resources. ...

February 9, 2025 · 4 min · Markus Greiner