LiveCodes is a feature-rich, open-source, client-side, code playground that supports 80+ languages and frameworks. Playgrounds can be embedded in web pages. A powerful, yet easy-to-use, SDK allows creating and communicating with playgrounds.
Nevertheless, LiveCodes is free, with no subscriptions, no limits to usage, no ads and no account required. It is MIT-licensed which allows its use, distribution and modification even for commercial projects.
Most other code playgrounds with comparable features and language support are either paid, or have significant, progressively increasing, limitations on free plans. Limitations restrict number of users, private projects, compute time to run code, available RAM or CPU, editable playgrounds and more. This is understandable. Servers cost money, and high usage of running code on servers can be expensive.
LiveCodes solves this problem by running code on user devices not servers. So, instead of selling VMs and cloud computing, LiveCodes works on the client-side, and runs all the code (including compiling 80+ languages) in the browser. See how LiveCodes is different.