Online Crystal Compiler
Crystal is a programming language with Ruby-like syntax but compiled. Run Crystal code instantly in your browser.
# Online Crystal compiler
# Write Crystal code in this online editor and run it
def greet(name)
puts "Hello, #{name}!"
end
greet "Tutorsbot"
Crystal is a programming language with Ruby-like syntax but compiled. Run Crystal code instantly in your browser.
What is Crystal?
Crystal is a general-purpose language with Ruby-like syntax but static type-checking and ahead-of-time compilation to native code via LLVM. It targets macOS, Linux, and Windows with no runtime dependency, and concurrency is built into the language via channels (the Channel type) and fibers (lightweight threads).
Why run Crystal in a browser
The Crystal compiler is fast for small files but the standard library download plus the LLVM dependency is a hefty setup. A browser sandbox lets you write Crystal code and run it without that overhead — our execution platform compiles and executes in a few seconds.
Common Crystal tasks
Web frameworks (Lucky, Amber, Kemal), command-line tools with built-in argument parsing, gRPC clients and servers, system utilities, and gradual migration from Ruby codebases (the syntax is intentionally similar). Crystal has nil-safe types (Int32 | Nil) and Channel-based concurrency built in. The sandbox runs Crystal 1.9.2.
Getting started with Crystal 1.9.2
Paste a snippet — def greet(n); puts "hi, #{n}"; end; greet "Tutorsbot" — hit Run, see stdout. The highlighter recognises Crystal syntax: type inference, def/end, string interpolation with #{...}, the unless modifier, and Symbol literals like :ok.
Why use the Crystal online compiler?
- Crystal 1.9.2
- Ruby-like syntax
- Compiled language
- Type inference
Frequently Asked Questions
- Is the Crystal online compiler free?
- Yes — Tutorsbot's Crystal compiler is completely free. No account required, no installation, and no usage limits.
- Do I need to install Crystal?
- No. The Crystal compiler runs entirely in your browser. No runtime, no SDK, no PATH configuration. Open the page and start coding.
- Is my Crystal code saved between sessions?
- Yes — your code autosaves to your browser's local storage so you can resume where you left off. You can also generate a shareable URL.
- Can I share Crystal code with others?
- Yes. Click the Share button to copy a URL that encodes your script. Anyone with the link can open and run it instantly — no account required on their end.
- Is the Crystal compiler safe to use?
- Absolutely. Every program runs in an isolated sandbox. Your local system is never exposed to the executed code, and nothing is persisted after the execution window.