> ## Documentation Index
> Fetch the complete documentation index at: https://extension.js.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Announcing Extension.js 3.0.0

> Extension.js 3.0.0 ships faster Rspack-powered builds, Firefox Manifest V3 support, and first-class TypeScript for cross-browser extension development.

<Update label="v3.0.0" description="February 18, 2026" tags={["release", "major"]}>
  Extension.js 3.0.0 is now available.

  This release focuses on one thing: helping teams ship production browser extensions with less setup, clearer workflows, and better defaults across Chrome, Edge, and Firefox.

  ## What ships in v3

  **Version 3.0.0**

  * Stronger cross-browser workflows across Chrome, Edge, and Firefox with one command surface.
  * Expanded template experience for modern stacks including TypeScript, React, Vue, Svelte, and Preact.
  * Improved development update behavior with clearer hot module replacement (HMR), hard-reload, and restart-required boundaries.
  * Better production confidence workflows across troubleshooting, security checks, performance checks, continuous integration (CI) templates, and Playwright end-to-end (E2E) testing.
  * More predictable project configuration through `extension.config.js` and browser-aware build output.
  * A cleaner documentation and homepage experience designed for faster onboarding and lower cognitive load.

  ## The day-one flow is simpler

  Use one path from project creation to production output:

  1. `create` to scaffold.
  2. `dev` to iterate quickly.
  3. `build` to generate production artifacts.
  4. `start` or `preview` to validate production behavior.

  ```bash theme={null}
  npx extension@latest create my-extension --template=new-typescript
  cd my-extension
  pnpm dev
  pnpm build
  ```

  ## Better for teams, not just demos

  v3 is designed for real teams maintaining real extension codebases:

  * Typed templates and framework-first baselines reduce setup drift.
  * Browser-targeted builds and flags make compatibility checks explicit.
  * Workflow docs now map directly to release confidence tasks.
  * The standard delivery flow now includes security and performance guidance.

  ## Who this release is for

  * You are migrating from custom extension build scripts.
  * You are moving from app development to extension development.
  * You are standardizing extension developer experience across multiple repos and contributors.

  ## Upgrade notes

  If you are already using Extension.js:

  * update the package to latest,
  * prefer canonical template slugs (`new-react`, `new-typescript`, `new-vue`, etc.),
  * keep your command flow aligned with `create` → `dev` → `build`.

  ## Thanks

  Thanks to everyone building with Extension.js, reporting issues, and improving docs and templates with feedback.

  v3 is a major step forward, and we are just getting started.

  Cezar Augusto<br />
  Creator and Lead Developer, Extension.js
</Update>