The cross-browser extension framework
Build browser extensions for Chrome, Edge, and Firefox with one modern workflow. Extension.js handles manifest compilation, browser-specific output, reload behavior, and packaging so you can focus on product features.
npx extension@latest create my-extensionFrom developers worldwide
Real feedback from developers and teams experimenting with Extension.js.
Watch the full developer workflow
From scaffold to running extension, in one modern toolchain.
Pick your framework. Keep your workflow.
Start with production-ready templates for React, Vue, Svelte, TypeScript, or JavaScript.
React
Mature React ecosystem with reusable components, strong tooling, and scalable patterns for production extension interfaces.
Open template
Preact
React-like developer experience with lighter runtime, faster startup, and smaller bundles for performance-sensitive extensions teams.
Open template
Vue
Single-file component workflow with clear conventions, rich ecosystem plugins, and maintainable architecture for browser extensions.
Open template
Svelte
Compiler-first approach delivering concise components, minimal runtime overhead, and excellent performance for interactive extension UIs.
Open template
TypeScript
Type-safe foundation that improves refactoring confidence, collaboration clarity, and long-term maintainability across extension codebases.
Open template
JavaScript
Fastest setup for rapid prototyping, quick iteration, and shipping functional extensions without upfront type-system complexity.
Open templateBacking the open source core
Sponsors help us ship faster releases, better developer experience, and long-term reliability for extension teams.
Developer FAQ
Practical answers for setup, cross-browser support, and production delivery.
How fast can I launch my first browser extension?+
Most developers scaffold and run a working extension in minutes with the create command and starter templates.
Can one Extension.js project target Chrome, Edge, and Firefox?+
Yes. Extension.js is built for cross-browser extension development, with one command workflow and browser-aware build output.
Do I need to abandon my existing web stack?+
No. Use React, Vue, Svelte, TypeScript, or JavaScript templates and keep a familiar developer experience.
Is Extension.js ready for production teams?+
Yes. Teams use Extension.js to standardize extension build, test, and release workflows while keeping code maintainable.
Where should I start in the docs?+
Start with Getting Started, then follow the first-extension tutorial and template guides for your preferred stack.