Is this Haskell Online Compiler free to use?

Yes, Haskell Online Compiler is 100% free to use online with no installation or account required.

How do I run code using Haskell Online Compiler?

Simply type or paste your source code into the editor and click the Run button to view the output in the console.

Can I use Haskell Online Compiler on mobile devices?

Yes, the compiler is fully responsive and compatible with Android, iOS, Windows, macOS, and Linux web browsers.

Haskell Online Compiler

Write, compile, and run Haskell code online directly from your browser with our free Online Haskell Compiler. Test functional programming concepts, pure functions, recursion, lists, and type-safe code without installing the Glasgow Haskell Compiler (GHC) or configuring a local Haskell development environment.

How to Use This Haskell Compiler

Write or paste your Haskell code
Enter your program in the Code Editor. You can test functions, lists, pattern matching, recursion, higher-order functions, and other Haskell features supported by the compiler environment.
Click the Run button
Select Run to compile and execute your Haskell program. If your code contains a syntax, type, or runtime error, review the compiler feedback and correct the relevant expression.
Check the Output screen
Your program result appears in the Output panel. Use the available controls to copy, download, or delete the output before testing another program.

Key Features

Free Online Haskell Compiler: Write and execute Haskell programs directly from a modern web browser.
Zero Installation: No need to install GHC, GHCup, Stack, or configure a local Haskell toolchain for supported programs.
Instant Execution: Click Run and quickly view program output or compiler feedback.
Standard Haskell Syntax: Practice functions, recursion, pattern matching, guards, list comprehensions, tuples, and other core Haskell concepts.
Functional Programming Practice: Experiment with immutable data, higher-order functions, function composition, and lazy evaluation concepts.
Prelude Support: Use commonly available standard functions such as map, filter, foldr, length, sum, and reverse when supported by the runtime.
Dark and Light Mode: Switch the Code Editor theme for comfortable coding in different lighting conditions.
Output Controls: Copy, download, or clear generated output directly from the Output panel.

1. How do I print output in this Haskell compiler using putStrLn?

Haskell commonly uses putStrLn to print a line of text.

Enter the code in the Code Editor, click Run, and view the result in the Output screen.

You can also print values with print:

2. Do I need to install GHC to use this compiler?

No. You can use this Online Haskell Compiler directly from your browser without installing GHC or setting up a local Haskell development environment for supported programs.

A local GHC setup may still be preferable for larger projects, package management, advanced debugging, Cabal or Stack workflows, and applications that require external dependencies.

3. Are standard Prelude functions supported in this environment?

Common Haskell functions provided through the standard Prelude can generally be used when they are available in the configured compiler environment.

For example:

Other commonly used functions include filter, sum, length, head, tail, reverse, and foldr. Support for external Haskell packages may vary.

4. Can I use recursion and pattern matching in this Haskell compiler?

Yes. Recursion and pattern matching are core Haskell programming techniques and can be used in standard Haskell code.

This makes the compiler useful for practicing functional programming, learning Haskell’s type system, and testing small algorithms quickly.