About
A quieter place to run code
Code Arena is a free, browser-based workspace for writing and running JavaScript, TypeScript, and Python. There is no account, no install, and no project setup. You open an editor, type a small program, press Run, and read the output.
The product exists because most “online compilers” try to be full IDEs, course platforms, or social networks. We wanted the opposite: a calm scratchpad that is safe enough to share in a classroom and simple enough to use in a spare minute.
What you can do here
The JavaScript, TypeScript, and Python editors use the same Monaco surface you would expect in a desktop tool. When you run a snippet, Code Arena sends the source to an isolated Vercel Sandbox. The sandbox has no outbound network by default, a time limit, and a size limit. That keeps experiments self-contained and reduces abuse.
JavaScript includes an AST tab. You can click a node in the tree and jump to the matching source range. That is meant for learning, not as a novelty: nesting, calls, and operator precedence become visible.
Share copies language and source into a URL. Anyone with the link can open the same snippet. Treat that link like a public document — never put secrets in it. The sharing guide explains what the token contains.
Battle mode is an optional 1v1 practice arena with a short timer. It is for fun and warm-ups, not for ranked credentials or paid wagers.
Who it is for
Students use Code Arena to try a first loop or to read an error without installing Node or Python. Teachers use it to project a live editor and to send a link instead of a zip file. Developers use it when a five-line idea does not deserve a new repository.
It is not a place to build a production app, install packages, or keep private company code. When you need files, tests, git, or the internet, move to a local setup. The online vs local guide describes that split in more detail.
How we think about safety
Untrusted code on a shared service needs a box. Sandboxing protects the platform and other users. It does not make pasted secrets safe. If you would not post the text in a public chat, do not Run it here and do not Share it.
We rate-limit runs and reject oversized sources so one person cannot crowd out everyone else. Timeouts stop accidental infinite loops from hanging a sandbox. Those limits are documented in the timeouts and rate limits article.
Learning material
The Learn section is original writing about this playground: how to read JavaScript and Python errors, what an AST is, how type stripping differs from tsc, and how to share snippets without leaking more than you meant to. Guides stay next to a working editor so you can try the idea in the same tab.
We would rather publish fewer useful pages than a pile of generated stubs. If a guide is wrong or unclear, use the contact form — we read those messages.
Who runs Code Arena
Code Arena is built and operated by Shahin Hussain. It is an independent educational tool, not a venture-backed IDE company. The site may show advertising on Learn and guide pages after you accept advertising cookies. Ads are never placed next to Run, Share, Copy, or Reset.
Privacy, cookies, and terms are published on this site. If you have a question about data, a bug in the sandbox, or a classroom use case, write through Contact.