Fiddle Sites To Test Your Code


CC 2.0 image courtesy Judy Dean on Flickr

Fiddle sites have expanded lately and there’s a fiddle for most technologies. A fiddle site is a code playground or sandbox where developers can experiment with code without having to create sample projects in an IDE. Typically these websites feature:

  • a code window with syntax highlighting
  • a preview pane to see your results
  • code validation and code clean-up capabilities
  • the ability to save your work to your account or download it your machine
  • the ability to share your code snippets via short URL
  • free access (with some premium services requiring payment)


The following is a list of some of the major fiddle sites broken down by language:

C++ C++ Fiddle
C# C# Pad | .NET Fiddle
CSS CodePen | CSSDeck | Fiddle Salad | JS Bin |
CoffeeScript Fiddle Salad
F# .NET Fiddle
Go Go Playground
HTML CodePen | CSSDeck | Fiddle Salad | JS Bin |
JavaScript CodePen | CSSDeck | Fiddle Salad | JS Bin |
Markdown | Fiddle Salad
NodeJS | RunKit
PHP PHP Fiddle | PHP Tester
Python Python Fiddle
R R-Fiddle
Regex Refiddle | RegExr
Ruby Ruby Fiddle
Rust Rust Playground
SQL SQL Fiddle
Scala | | Scala Kata
Swift IBM Swift Sandbox
VB.NET .NET Fiddle

Multi-Language Sites

Some sites can perform checks against multiple programming languages at once. If you are also looking for one editor that has multi-language support, use the sites below:


The above tools allow you to test your code quickly and easily. You can tweak the source code on a site until you are happy with it and then incorporate it into your project. This allows you keep your developer machine free of projects created to just test and debug code.

Is there a web-based sandbox tool you use not listed here? Share it in the comments below.

About Ken Cenerelli
I am a technical writer/programmer writer/content developer, .NET developer, Microsoft MVP, public speaker, blogger, and Microsoft Azure nerd. I blog about technology at and am on Twitter via @KenCenerelli.

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