🔍 Debugging in Ruby: irb, pry, byebug, and debug — What You Should Know

May 21, 2025

If you’ve ever felt stuck trying to figure out why your Ruby code isn’t behaving as expected, you’re not alone. The good news? Ruby has several powerful tools to help you debug like a pro.

Here are 4 tools every Ruby developer should know — whether you’re a beginner or a seasoned dev:

🧪 irb — Interactive Ruby

The classic. irb is a simple REPL (Read–Eval–Print Loop) that comes built into Ruby. It’s great for quickly testing snippets of code.

$ irb
> 2 + 2
=> 4

📌 Perfect for quick math, method tests, or object inspection.

🔧 pry — Your Debugging Superpower

Think of pry as irb, but on steroids.

Add binding.pry to your code to pause execution and explore the state of your app in an interactive session.

def greet(name)
  binding.pry
  puts "Hello, #{name}!"
end

✨ Features:

• Syntax highlighting
• Method navigation
• Command history

🐞 byebug — Classic Step Debugging

Want to pause and step through your code line by line? Use byebug.

require 'byebug'

def sum(a, b)
  byebug
  a + b
end

You’ll get a console where you can:

• Step into methods (step)
• Go to next line (next)
• Continue execution (continue)
• Inspect variables (p some_var)

🐛 debug — The Official Ruby Debugger (>= 3.1)

Ruby 3.1+ ships with the new debug gem by default.

Add binding.break in your code and run with:

ruby -r debug your_script.rb

✅ Modern features:

• REPL integration
• Remote debugging
• VSCode integration
• Better performance

🚀 Summary

ToolBest ForBuilt-In?irbQuick testing & learning

✅ YespryIn-depth debugging & exploration

❌ InstallbyebugStepping through code

❌ InstalldebugFull-featured modern debugging

✅ Ruby ≥3.1

💬 Final Thoughts

Debugging doesn’t have to be painful. With tools like pry, byebug, and the official debug gem, Ruby gives you everything you need to investigate and solve problems efficiently.

🔧 Pro tip: Even seasoned devs drop binding.pry like breadcrumbs through their code.

👉 Which one do you use the most? Or is there a different trick you swear by? Let’s share tips in the comments ⬇️

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