Plasmo
FreemiumSupercharge your browser extension development.
Scores
About
Plasmo is an open-source browser extension SDK built around a battery-packed development philosophy. It auto-generates the manifest.json from file structure, provides first-class React and TypeScript support with live Hot Module Replacement, and ships built-in APIs for storage and inter-context messaging. The pnpm create plasmo scaffold gets a working extension running in minutes, eliminating the manual configuration work that typically dominates early extension development.
Beyond the core framework, the Plasmo ecosystem includes Browser Platform Publisher (BPP) — a GitHub Action that automates submission to the Chrome Web Store, Firefox Add-ons, and Edge Add-ons — and Itero TestBed, a commercial cloud staging environment for distributing beta builds to testers outside the store review cycle. The Content Scripts UI (CSUI) feature lets developers inject React components directly into host pages with automatic Shadow DOM wrapping.
As of early 2026, Plasmo has ~12,900 GitHub stars and a significant community, but has attracted concern about long-term maintenance. The last tagged release (v0.90.5) was in May 2024, and reliance on the Parcel bundler creates friction with modern tooling such as TailwindCSS v4. Developers evaluating Plasmo for new production projects should weigh its strong initial DX against these ecosystem health signals.
Key Features
- Declarative manifest generation — manifest.json auto-generated from file structure, no manual permission declarations
- React + TypeScript first-class with HMR — JSX, typed APIs, and live reload out of the box
- Content Scripts UI (CSUI) — inject React components into host pages with automatic Shadow DOM wrapping
- Built-in Storage and Messaging APIs — typed cross-context communication between popup, background, and content scripts
- Multi-browser targeting — single codebase builds for Chrome MV3, Firefox, Edge with minimal config
- Browser Platform Publisher (BPP) — GitHub Action for automated publishing to all major extension stores
- .env file support — environment variables work natively like Next.js/CRA
- Itero TestBed — commercial cloud staging for beta distribution outside store review queues
Pros
- Dramatically reduces setup friction — working extension with HMR scaffolded in under five minutes
- Excellent TypeScript and React DX — strongly typed APIs and auto-complete-friendly structure
- Cross-browser targeting is nearly automatic — Chrome and Firefox from a single codebase
- Useful built-in abstractions — Storage, Messaging, and CSUI are genuine batteries, not thin wrappers
- Good docs and active Discord community for onboarding
Cons
- Maintenance concerns — last release May 2024; community doubts about long-term viability
- Parcel bundler dependency — slower builds and incompatibility with TailwindCSS v4 and other modern tools
- Vue and Svelte support is second-class — only React gets true HMR; others trigger full reloads
- Must learn 'the Plasmo way' — heavy abstraction means debugging requires understanding its conventions
- Occasional Windows toolchain issues reported by users
Pricing
Freemium- · Full open-source framework (MIT)
- · Browser Platform Publisher (BPP) GitHub Action
- · Unlimited local builds and browser targets
- · Cloud staging environment (Itero TestBed)
- · Beta distribution to real testers outside store review
- · Limited testers / builds per month
- · Expanded tester seats and build quota
- · Priority support
- · Advanced analytics on beta usage
Related Tools
Works well with (5)
Learning Resources
No resources yet — check back soon.
