Free Online Code Playgrounds — HTML, JavaScript, TypeScript, React, SQL, Python

A playground lets you write a few lines of code and see what happens, without installing anything. These playgrounds run entirely in your browser: your code is never uploaded and there is no account to make. Web pages and components run inside a sandboxed preview that cannot reach this site or the internet unless you switch that on, databases run on a copy of SQLite or PostgreSQL built for the browser, and Python runs on a version of Python built for the browser. The first run of a heavier playground downloads its engine once, and the browser keeps it afterwards. Add several files to a project, share it with a link, or download everything as one zip. Use them to try an idea quickly, to learn a language by changing small examples, to check how a query behaves before it goes into an application, or to share a short demo with a colleague without setting up a project first.