Local code sessions
in your class

Host coding sessions on your own machine for
tests, exams, or everyday classwork.

Local

No cloud service, no third party. Your students' work stays on your machine, and only your machine.

Free

It's free now and will be free forever.

Open source

We don't have anything to hide. The code is a bit of a mess so good luck reading it.

Let students make the editor their own

HTML
1 Hello world!
CSS
1 body{ color: red; }
JS
1 console.log("Hello world!");
Hello world!

Resizable panels

Layout switcher

Theme switcher

Saves preferences

Try the editor

Lock down a test
in a few clicks

Skip the manual SEB setup. CodeLo creates a ready-to-use .seb file for your session, with everything configured for you.

Blocks new tabs & windows
No navigation controls
Locks to session URL only
Hidden address bar & dev tools

Made easy for you with only 3 steps

01

Start the session

Set your preferences and launch the session.

02

Students join

They open the link or SEB file you share.

03

Collect the work

Students submit in one click, and it lands straight in your folder.

Full instructions

Supported languages

HTML
JavaScript
CSS
More languages soon

This project started from my own frustration. I couldn't find a solution that fit my needs while also being something teachers could trust and feel comfortable using. With the skills I had, I decided to build my own. From the start, I wanted it to be local-first, no login and easy to use for both teachers and students.