CodeSandbox

CodeSandbox is the long-running cloud IDE for web development — instant shareable sandboxes for React, Vue, Angular, and more, used in thousands of open-source projects. Its AI play is Boxy, an AI coding assistant deeply integrated into the cloud environment with access to the entire codebase, giving it project-wide context that standalone assistants lack.

Boxy does intuitive refactoring (select an element in the app preview and ask it to refactor the associated code), contextual code generation, automatic commit message suggestions from branch diffs, and code explanations for learning. AI features require manual opt-in and are available on Personal Pro and Team Pro subscriptions. CodeSandbox also runs an AI Research Program offering volunteers free AI access in exchange for feedback. The honest limitation: Boxy's strengths are concentrated on web development inside CodeSandbox itself — it is not a general-purpose coding agent for arbitrary local codebases.

Sign up at codesandbox.io — projects run in the browser. Opt in to Boxy's AI features from settings; AI access requires a Personal Pro or Team Pro subscription.