Replit

Free online compiler supporting 70+ languages including Java, Python, C++, JavaScript.

Code editor redefined and optimized for building and debugging modern web and cloud applications. Developed by Microsoft.

Coding Assistant that lets you search, define, and reuse code snippets directly in your IDE. Free for individual and small organizations.

Collaborative calculation in the cloud. Browser access to full Ubuntu with built-in collaboration and lots of free software for mathematics, science, data science, preinstalled: Python, LaTeX, Jupyter Notebooks, SageMath, scikitlearn, etc.

BBEdit is a popular and extensible editor for macOS. Free Mode provides a powerful core feature set and an upgrade path to advanced features.

Development Environment, Tooling Platform and Application Framework.

Android Studio provides the fastest tools for building apps on every type of Android device. Open Source IDE is free for everyone and the best Android app development. Available for Windows, Mac, Linux, and even ChromeOS!

An open-source client-side code playground that supports 90+ languages/frameworks. Projects can be saved, exported, shared, synced, deployed (to GitHub Pages) and embedded in web pages. Mobile-friendly. Can be self-hosted. Free for unlimited usage. No account required.