Online compiler, debugger and visualizer
Online TypeScript compiler
Run TypeScript online without any setup: write .ts files and run them directly on Node.js 22, with input, several files and test cases.
- Free
- No sign-up
- Real compilers
- Works on phones
interface Student { name: string; marks: number[];} const average = (s: Student) => s.marks.reduce((a, b) => a + b, 0) / s.marks.length; const ravi: Student = { name: "Ravi", marks: [78, 91, 85] };console.log(`${ravi.name}: ${average(ravi).toFixed(1)}`);What you can do
Real TypeScript (Node.js 22)
Your code is compiled and run by the real TypeScript toolchain on our servers, not a simulation, with the exact errors you would see on your own computer.
Input while it runs
Programs that read input (Scanner, input(), scanf, cin) ask for it in the console as they run, just like a terminal. Or prepare the input in advance.
Test cases
Add inputs with the expected output and run them all with one click. See which lines differ, like on a coding judge, for any code you write.
Errors explained
Compiler and runtime errors link to the exact line, with a plain-English explanation of what went wrong and how to fix it.
AI help that sees your code
Ask why a test fails or what an error means. The assistant sees your files and the real output, and can fix the right line for you.
Code together live
Share a link and code with friends or students in real time: shared cursors, edits, runs and test results.
How it works
- 1
Click "Open the TypeScript compiler". A project with a ready-to-run main.ts opens.
- 2
Write your code. Files save automatically in your browser as you type.
- 3
Press Run (Ctrl+Enter). If the program reads input, type it in the console.
- 4
Add test cases to check your program against expected outputs, or share a live link to code with someone.
Questions and answers
Do I need to compile it first?
No. Press Run and the TypeScript runs directly; types are stripped automatically.
Is it free?
Yes. Running, debugging, tests and live sessions are free, with no sign-up.
Where are my projects saved?
In your browser, on your device, automatically as you type. Nothing is lost when you close the tab. They stay until you delete them.
Is my code safe to run?
Every program runs in its own isolated sandbox with no internet access and strict limits on time, memory and processes, and is deleted when it finishes.