Comparison
Extro vs ExtensionStart: free starter vs paid kit
Extro is a free, open-source browser-extension starter by TurboStarter, and it's good. If you're not charging for your extension, it may be everything you need; start there. This page is for the case where you are charging.
Facts about other products on this page were last verified in July 2026. If something is out of date, email us and we'll fix it.
What Extro is
Extro (MIT, ~400 GitHub stars, actively maintained as of July 2026) is TurboStarter's open-source extension starter: WXT + React + TypeScript with a Supabase backend, shadcn/ui components, Tailwind, Bun, and Biome. Out of the box it covers OAuth authentication, storage, messaging, content-script UI, i18n, analytics (OpenPanel), unit tests, CI/CD pipelines, and one-click publishing: a well-chosen foundation, and notably one that lands on the same framework conclusion we did (WXT; it even keeps a legacy Plasmo branch).
What it doesn't have, by its own README as of July 2026, is billing: the feature list marks it "coming soon". There's also no paywall/gating layer, and its test coverage is unit-level rather than end-to-end against a built extension. None of that is a criticism of a free project; it just draws the line between the two products precisely.
Side by side
| Extro (free, open source) | ExtensionStart (paid kit) | |
|---|---|---|
| Price | Free, MIT | One-time purchase, private repo access |
| Stack | WXT + React + TS, Supabase, shadcn/ui, Tailwind, Bun, Biome | WXT + React 19 + TS, Firebase, Tailwind 4, custom UI kit on Base UI |
| Auth | OAuth authentication | Google sign-in via MV3 web-auth-flow + offscreen fallback, email/password, anonymous-first linking that preserves the uid |
| Billing | "Coming soon" (README, July 2026) | Stripe checkout/portal/webhooks; monthly, yearly, lifetime; card-free trials enforced server-side |
| Entitlements | n/a (no billing yet) | Webhook-written, server-authoritative; client state is UX only |
| Paywall engine | Not included | Gate engine: timing presets, cooldowns, chaining, Chrome Web Store policy guardrails |
| Tests | Unit tests + CI | 411 unit tests + 12 Playwright e2e specs against the built extension + Firestore rules tests + remote-code audit |
| Publishing | One-click publishing (Chrome + Firefox) | CI pipeline with staged Chrome rollout, Firefox, and Edge Partner Center |
| Extras | Analytics, i18n, custom fonts, experimental AI integration | Marketing-site template, setup wizard + module pruner, AGENTS.md/llms.txt, docs |
The honest recommendation
Free extension, or monetization is a distant maybe: use Extro (or plain WXT) and keep your money. Charging from day one, or converting an existing extension to paid: the billing/entitlement/paywall layer is where the MV3-specific landmines live: hosted checkout is the only architecture MV3 allows, entitlements must be server-written or they're forgeable, and paywall timing is a store-policy question as much as a conversion one. That layer, tested end-to-end, is what ExtensionStart sells.
Frequently asked questions
Is Extro free?
Yes. Extro is open source under the MIT license, maintained by TurboStarter. You can clone it from GitHub and ship commercial extensions with it at no cost.
What's the main difference between Extro and ExtensionStart?
Monetization. Extro covers the free-extension foundation well (auth, storage, messaging, i18n, unit tests, CI, publishing). ExtensionStart is a paid kit whose core is the paid-extension layer: Stripe billing wired to server-enforced entitlements, a paywall gate engine with store-policy guardrails, and end-to-end tests against the built extension.
Does Extro include Stripe billing or paywalls?
Not as of July 2026; its README lists 'Billing (coming soon)' among the features. If your extension charges money today, you'd be building the billing, entitlement, and paywall layer yourself on top of Extro.
Extro uses Supabase and ExtensionStart uses Firebase. Does that matter?
Less than it seems. Both are solid managed backends with auth and a database. Pick based on which ecosystem you know and what your product needs; the harder extension-specific problems (MV3 auth flows, webhook-driven entitlements, service-worker lifecycle) exist on both.