Jenny Wilson 
Two frameworks come up most often when developers start a serious browser extension project in 2026: Plasmo and LightningAddon. They solve different problems, target different audiences, and make different trade-offs. Here is a direct comparison based on what actually matters when you are building a SaaS product on top of an extension.
What Plasmo Is
Plasmo is an open-source framework with a file-based routing model similar to Next.js. You create files in specific directories and Plasmo automatically generates your popup, content scripts, and background service worker. It has good TypeScript support, a built-in dev server with hot reload, and integrates with most popular UI frameworks.
Plasmo is the right choice if:
- You want an open-source solution with no upfront cost
- You are building a relatively simple extension (no billing, one backend)
- You value the file-based convention approach
- You are comfortable piecing together auth and billing yourself
What LightningAddon Is
LightningAddon is a paid, architecture-first monorepo boilerplate. It does not use a file-based convention system — instead, it gives you full control over each extension context (popup, background, content scripts, in-page apps) as separate Vite applications assembled by a custom build tool called repo-assemble.
LightningAddon is the right choice if:
- You are building an extension that needs to charge users (Stripe billing is pre-wired)
- You want Firebase and Supabase both included with full parity — swappable with one env var
- You need Chrome and Firefox from a single codebase without branching
- You want typed messaging across all extension contexts enforced by TypeScript at compile time
- You want shadow DOM isolation for content scripts without configuring it yourself
The Core Architectural Difference
Plasmo abstracts the extension build system away from you. That is its biggest strength and its biggest weakness. For simple projects, the abstraction is convenient. For complex products, you sometimes hit the edges of what the abstraction supports and have no clean escape hatch.
LightningAddon does the opposite: it shows you the build system. You can read every line of it. The Turborepo monorepo with separate Vite apps per context is more code to understand upfront, but it is infinitely more flexible when your product grows beyond what a convention-based system was designed to handle.
Billing
Plasmo does not include billing. You can build it yourself on top of Plasmo, but you will need to figure out the service worker pattern for Stripe (or accept the CORS issues that come from doing checkout in the popup). This typically adds several days of work.
LightningAddon ships with Stripe checkout and customer portal already wired through the service worker. You configure your Stripe keys and it works. The implementation is visible in the source code, so you can read and modify it.
Auth
Plasmo does not include auth out of the box. The Plasmo team has published guides for various providers, but the integration work is yours.
LightningAddon ships both Firebase and Supabase auth pre-integrated, with identical feature parity. You pick one with an environment variable. Both include cloud functions/edge functions with Stripe webhook handlers.
Multi-Browser
Plasmo generates separate Chrome and Firefox manifests and handles some of the API differences. For basic cases, this works well.
LightningAddon takes a more explicit approach: getExtensionApi() detects the browser at runtime and returns a normalized API object. The build system produces separate packages for Chrome and Firefox. This gives you more control and makes the multi-browser handling visible and debuggable rather than hidden inside a framework.
Cost
Plasmo is open source and free to use. LightningAddon is $149 one-time with lifetime updates.
The Decision Framework
If you are building a hobby project, a simple utility, or something you want to experiment with before committing, Plasmo is a reasonable starting point. It is free and gets you moving quickly.
If you are building something you intend to charge for, support Chrome and Firefox, and maintain for more than a few months — the architecture decisions in LightningAddon are almost certainly worth $149. The time you save not building auth, billing, and multi-browser infrastructure pays for itself in the first week.
Neither is objectively better. The right choice depends on what you are building and how serious you are about shipping a real product.
