Resize Observer API with Stimulus

Occasionally, parts of our application that depend on the size of the screen can break because of the user resizing the browser window. [more inside]

RSpec book update: Testing in isolation with mocks (and friends)

I just shipped a new chapter for the current edition of Everyday Rails Testing with RSpec. In this release, I’ve totally replaced my introduction to testing in isolation with mocks (and stubs, and fakes, and spies, and doubles, oh my). My beliefs on when and how to mock have changed a lot since the last major release of the book, and this updated chapter reflect my newer opinions. I hope you find it useful!

Reject Nested Attributes in Rails

A detailed write-up on using reject_if with accepts_nested_attributes_for to make nested associations optional in Rails forms

Running ruby on jupyter notebooks

You’ve maybe heard about Jupyter notebooks - an awesome web application which allows you to run python code in a browser. There are another similar project - Livebook which allow running Elixir code in browser. [more inside]

Heroku SSL Revisited (2025 Edition)

I thought I knew the “right” way to set up SSL with Heroku and a CDN like Cloudflare, and I was wrong. Here’s what I learned.

Three videos about Data objects in Ruby

I recorded three videos (one each week) about Using Data objects in Ruby and published them in a playlist. They correspond to the articles I published so far about this topic.

Beyond translations in Stimulus: formatting dates, time and currency

Exploring JavaScript’s Intl object that provides language-sensitive string comparison, number formatting etc. And creating a custom class for a better DX: https://railsdesigner.com/beyond-translations-in-stimulus/ [more inside]

More about how to create a Data class in Ruby

I wrote a short exploration about How to create Data classes in Ruby using block definition or inheritance definition and showed the differences between them

✨ Generate PDFs in pure Ruby using Chrome — no Selenium, Puppeteer, or Node required

Just published a new proof of concept gem: bidi2pdf — a pure Ruby tool for generating high-quality PDFs using Chrome’s new WebDriver BiDi protocol. 🛠 What it does: [more inside]

Demystifying Rails Generators: What I Wish I Knew

Rails generators, and their underlying Thor integration, can be surprisingly opaque — even for experienced developers. I recently found myself deep in this rabbit hole, frustrated by the lack of clear documentation and practical guidance. So I wrote the article I wish I’d found back then. If you’ve ever struggled to understand or customize Rails generators, this guide breaks it down in a way that’s approachable and practical. [more inside]

Migrate from importmap to esbuild

Importmap is a great tool, but unfortunately it isn’t a silver bullet for everything. I decided to move away from importmap to esbuild for one of my projects because of it was so tricky to setup it to use with flowbite. [more inside]

Create an Email Drip Campaign Using Rails Vault

Time Formatting with strftime Function in Ruby

Time Formatting with strftime Function in Ruby

Kamal Deployment: The Newest Form of Self-Torture

Struggling with Kamal 2 for Rails deployments? This detailed guide walks through common pitfalls and their solutions when setting up Kamal with Rails 8, Solid Stack, and multi-environment configurations. Learn practical workarounds for Docker permissions, credentials management, and Shrine file uploads that will save you days of frustration. [more inside]

Creating a Ruby Gem to Add AI Power to the Trix Text Editor – Trix-Genius v0.0.5 Germ

In my latest article, I’m diving deep into how to add AI power to your Rails application by creating a custom gem: trix-genius. Learn how I’ve integrated AI features into the Trix text editor, and how you can do the same for your applications! ✨ [more inside]

Vibe Coding

Time to stop hiring $100k/year developers and hire an intern for $10k/year and pay $100/year for an AI Agent. The intern doesn’t even need to understand the code it is generating and just help guide it to the solution.

Your Product Should Be Shiny. Your Stack Should Be Boring.

🚀 Supercharging Trix Editor with AI & Rails Generators! 🧠

Have you ever wanted to extend Trix Editor in Ruby on Rails and automate its setup? In my latest article, I share how I’m building Trix Genius, a gem that enhances Trix with AI-powered features. [more inside]

nanoc-webpack.rb adds webpack to nanoc :)

nanoc-webpack.rb is a nanoc filter that adds webpack support to nanoc. The filter connects nanoc to the JavaScript, TypeScript, and nodejs ecosystems.

Hotwire cheatsheet

I’ve tried to create a useful cheatsheet about Hotwire using AI, but I ended up with a final result that was almost like a book. [more inside]

🚀 Modularize Your Code, Improve Organization! 🚀

In my latest blog post, I dive into how you can modularize your code and improve your application’s structure by automating the creation of Ruby gems. 🛠️ [more inside]

2025 Reminder That DHH Is a Total Idiot!

2025 Reminder That DHH Is a Total Idiot!…

Implementing an Inventory Module in Ruby on Rails: Handling Concurrency with Database

When implementing an inventory module in a Ruby on Rails application, ensuring consistency in stock levels is crucial. If multiple users try to purchase the same item simultaneously, concurrency issues can lead to overselling. In this post, we’ll explore two approaches to handling inventory management: using a simple counter with database locks to prevent race conditions & improving performance and reliability using SKIP LOCKED for efficient inventory allocation. [more inside]

🚀 Mastering Rails Migrations: The Power of change_table 🚀

Are you handling database migrations efficiently in your Ruby on Rails projects? Many developers use add_column, rename_column, and remove_column separately—but did you know that change_table can streamline multiple modifications in a single block? [more inside]

Touch Events (swipe) using Stimulus

Create a touch-ready carousel + (Tinder-like) swipe functionality: