Online compiler, debugger and visualizer
Code together, live
Share a link and write code with someone else at the same time, like a shared document for programs. Everyone sees the edits, cursors, runs, test results and the debugger's position as they happen.
- Free
- No sign-up
- Real compilers
- Works on phones
def fib(n): a, b = 0, 1 for _ in range(n): a, b = b, a + b return a n = int(input("How many? "))print([fib(i) for i in range(n)])What you can do
Real-time editing
Type in the same file at once without overwriting each other.
Cursors with names
Each person's cursor and selection shows in their colour, with their name.
Shared runs and input
When someone runs the program everyone sees the output, and anyone who can edit may type its input.
Follow and present
Follow someone to see what they see. View-only guests follow the presenter automatically.
Roles
Choose who can edit and who can only watch; remove people; end the session for everyone.
Invite by link or email
Copy the link, send it on WhatsApp, or email it from your own email app.
How it works
- 1
Open a project and click Share.
- 2
Enter your name and start a live session.
- 3
Send the link. People join by typing their name.
Questions and answers
Do the others need an account?
No. Whoever has the link joins by typing a name. You can make them view-only or remove them.
How many people can join?
Up to 100 people in one session, for example a whole class watching the teacher.
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.