Can I use Rails or external gems?

No. The playground runs single-file Ruby programs against the standard library only.

Do blocks, procs and lambdas work?

Yes. Standard Ruby language features run normally.

Is the Ruby playground free?

Yes, free with no account required.

main.rb

Input

Output

Become A Ruby Backend Engineer

All-in-one Ruby course for learning backend engineering with Ruby. This comprehensive course is designed for developers seeking proficiency in Ruby.

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Online Ruby Playground

Runs on Ruby 2.7.0 · Free · No signup required

A free online Ruby playground for backend engineers. Write Ruby, run it, and see output immediately — no rbenv, no bundle install, no signup. Ruby rewards experimentation, and this is the fastest way to try something: chaining enumerable methods to see what actually comes back, testing a block's return value, checking how a string method handles an edge case. Code runs server-side against a real Ruby interpreter, so results match what you would get from irb or a script rather than a simplified sandbox. Standard input is supported for programs that read from stdin. The environment runs single files against the standard library, which is enough for testing logic though not for gem-dependent code. If you are building real backends with Ruby and Rails, the playground sits alongside our backend projects and engineering courses.

Ruby Playground — Frequently Asked Questions

Can I use Rails or external gems?: No. The playground runs single-file Ruby programs against the standard library only.
Do blocks, procs and lambdas work?: Yes. Standard Ruby language features run normally.
Is the Ruby playground free?: Yes, free with no account required.

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Ready to build real backends rather than test snippets? Explore backend engineering courses and projects at MasteringBackend.