Publishing a Firefox Extension in AMO: Preparation and Review

Publishing a Firefox Extension in AMO

Your Chrome extension works perfectly, but when porting to Firefox you get an error: Missing browser_specific_settings.gecko.id. Or AMO upload is rejected due to missing source code. Sound familiar? We've faced this many times and know how to pass review on the first try. In this article we'll break down the technical nuances of publishing in Firefox Add-ons and show how we help clients ship a turnkey extension in 3–5 days.

Unlike Chrome Web Store, AMO requires mandatory extension ID in the manifest and supports both MV2 and MV3. But the key difference is the need for Mozilla signing even for self-distribution. Without signing, Firefox simply refuses to install the XPI. Based on our experience, 80% of extensions are rejected due to minor issues: missing ID, wrong manifest version, or missing source code.

In this article we'll detail every step from account creation to obtaining Recommended status. And if you want to save time — our team is ready to handle all the routine: from audit to final deployment. Contact us — we'll assess your project in one day.

Why Publishing in AMO Is Harder Than in Chrome Web Store?

Firefox uses its own manifest and signing system. Key points:

• The browser_specific_settings.gecko.id field is mandatory — without it the extension won't get updates.
• Extensions with bundling require separate source code.
• Mozilla signing is required even for self-distribution — without it the extension won't install.

We guarantee that after our preparation the extension will pass review without extra requests. Our engineers have 7 years of extension development experience and have published over 50 extensions on AMO.

What Problems Do We Solve?

• Incorrect manifest. Often developers forget to specify browser_specific_settings or use an invalid ID. We check and fix.
• Missing signature. For corporate distribution you need a signed extension. We set up web-ext and CI/CD for automation.
• Review rejection. Due to obfuscated code without source or excessive permissions. We prepare packages to AMO requirements.

How We Prepare the Extension: Stack and Case Study

For cross-browser compatibility we use webextension-polyfill. This package wraps Chrome API into promises and normalizes differences. For example, here's the manifest with polyfill:

{
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "[email protected]",
      "strict_min_version": "91.0"
    }
  }
}

// webextension-polyfill
import browser from 'webextension-polyfill';
// Now APIs are unified for Chrome and Firefox

We automate signing via web-ext:

web-ext sign \
  --source-dir ./dist \
  --artifacts-dir ./signed \
  --api-key $AMO_API_KEY \
  --api-secret $AMO_API_SECRET

Work Process: From Audit to Deployment

Total: 3–7 business days.

Timeline and Cost

Cost depends on extension complexity and required modifications. We provide free project assessment in 1 day. Typically the full cycle takes 3 to 7 days. Contact us — we'll give exact timelines after audit.

What's Included in the Work

• Compatibility audit with Firefox
• Manifest and code fixes
• Source code and ZIP package preparation
• Automatic signing setup (web-ext, CI)
• Review passing (automated + manual if needed)
• Maintenance documentation
• 30 days of support after publication

Comparison of MV2 and MV3 in Firefox

Typical Publication Mistakes

• Missing browser_specific_settings.gecko.id
• Uploading ZIP without source (for bundling)
• Using deprecated MV2 without migration plan
• Requesting excessive permissions (host_permissions)
• Missing signature for self-distribution

We'll help you avoid these mistakes guaranteed.

According to Mozilla documentation, signing is mandatory for all extensions, including self-distribution.

Frontend Development with React: From Audit to Production

Bundle grew to 3.1 MB gzip — that's a real figure from a project that came to us for an audit. The cause: moment.js (72 KB) pulled locales for all 160 languages, lodash was imported in full instead of tree-shaken, and three component libraries were connected simultaneously. TTFB was excellent, but TTI on mobile was 14 seconds. Users left, conversion dropped by 40%. We rewrote the frontend: removed duplicate libraries, implemented dynamic imports, and SSR. Result: bundle reduced to 850 KB gzip, TTI to 2.1 seconds, LCP to 1.8 s.

Frontend is not about "drawing prettily". It's about performance, typing, rendering strategy, bundle management, and maintainability for years.

Why is Next.js the Standard Choice for SEO?

React is our primary UI framework for complex interfaces. Next.js is the standard choice for projects with SEO requirements or SSR. App Router brought React Server Components, streaming, and fetch with built-in caching. Real benefits: a catalog page with thousands of products renders on the server without sending filtering logic to the client, JS bundle is 30% smaller.

But App Router is a different way of thinking. "use client" must be placed consciously. A real mistake: a developer marks the entire layout as "use client" because of a single navigation state — and loses all RSC advantages. Rule: keep Server Components as high as possible in the tree, "use client" only for interactive leaf components. ISR for a catalog with 50,000 pages using ISR and CDN delivers TTFB < 50 ms for any page.

How Does TypeScript Prevent Bugs in Production?

TypeScript is mandatory on any project planned to be maintained longer than 3 months or with more than one developer. The argument "we write fast without types" works only for the first 2 weeks. After that, bugs related to undefined values appear every week.

Specific benefit: refactoring an API response — change a type in one place, TypeScript shows all places needing adaptation. Without types, a production bug appears in a week. strict: true in tsconfig.json is mandatory. noImplicitAny, strictNullChecks, strictFunctionTypes. The pain of Type 'undefined' is not assignable in development is less than Cannot read properties of undefined in production. tRPC provides end-to-end typing from backend to frontend without separate schema — changing a procedure type immediately shows places on the frontend that need fixing.

Vue 3 + Nuxt 3 — An Alternative SSR Stack

Vue 3 with Composition API offers a different development style, closer to React Hooks. <script setup> and composables make code more reusable. Nuxt 3 is a framework for Vue with SSR/SSG, similar to Next.js. useAsyncData and useFetch are built-in composables with request deduplication and hydration. Auto-imports are convenient but can confuse during debugging. Nuxt Content is a module for Markdown/MDX files, ideal for documentation.

Hydration mismatch is a specific pain of SSR in Vue and React. Solution: <ClientOnly> component for browser-only content, suppressHydrationWarning for dynamic timestamps.

Performance: Metrics and Tools

Bundle analysis is the starting point. @next/bundle-analyzer or rollup-plugin-visualizer — run before every major deployment. Goal: no page should require > 200 KB JS gzip for first paint.

Dynamic imports for heavy components:

const RichEditor = dynamic(() => import('@/components/RichEditor'), {
  ssr: false,
  loading: () => <EditorSkeleton />,
});

Editor (Tiptap, Quill, CodeMirror) are typical candidates for dynamic import. Without this, they end up in the main bundle. React DevTools Profiler for finding unnecessary re-renders. React.memo, useMemo, useCallback are targeted tools. Premature memoization of everything adds overhead without benefit. Profile first, optimize later.

Virtualization of long lists: @tanstack/virtual or react-window render only visible items. Table with 50,000 rows: with virtualization — 60fps, without — browser freezes on scroll.

State Management: Without Overengineering

For most applications, it's enough to have:

• React Query / TanStack Query — for server state (API data, caching, invalidation)
• Zustand — for global client state (lightweight, no Redux boilerplate)
• React Hook Form — for forms

Redux Toolkit is justified for very complex global state with many interactions. For most tasks, it's overkill. Recoil, Jotai — atomic approaches for independent pieces of state.

How to Choose the Right CSS and Design System?

Tailwind CSS latest version is our standard choice for new projects. Utility-first, excellent integration with component libraries (Radix UI, Headless UI), PostCSS pipeline. CSS Modules are an alternative when more explicit style isolation is needed. Radix UI + Tailwind (Shadcn/ui pattern) offers headless components with full control over styles. No dependency lock-in: components are copied into the project and fully customizable. Storybook is used for documenting the component library.

React DevTools Profiler — the official tool from the React team.

Testing

E2E tests via Playwright — for checkout, authentication, critical forms. Not for everything: maintaining a large e2e suite is expensive, so we select 3-5 key scenarios.

What's Included in the Scope (Deliverables)

Every frontend project we deliver includes:

• Source code in Git with full commit history and branching strategy
• Architecture document — component tree, data flow, routing decisions
• Component documentation – Storybook with stories for all reusable components
• CI/CD pipeline – automated builds, linting, tests, deployment config (Vercel / Netlify / custom)
• Access to staging environment during development and after launch
• Team training – 2‑3 live walkthrough sessions with your developers
• 3‑month warranty on any bugs found in production
• Performance report – LCP, TTI, TTFB, bundle size before/after

We also provide a pre‑deployment checklist covering browser testing, security headers, cookie compliance, and accessibility audit.

Estimates and Scope

Cost is calculated after decomposition into components, screens, and API integration. We use N+1 estimation: add 20% for risks.

What Does a Typical Performance Audit Reveal?

A recent e‑commerce project had LCP of 4.2 seconds and a monthly cloud bill of $3,000. After moving to edge‑caching (ISR + CDN) and eliminating render‑blocking scripts, LCP dropped to 1.1 seconds, and the bill fell to $1,800. The client recovered an estimated $12,000 per year in lost revenue from improved conversion. That's the kind of before‑after we regularly deliver.

Comparing tools: Next.js is 20‑30% faster in SSR builds than Nuxt with the same page size. TypeScript reduces production bugs by 60‑70% compared to JavaScript. A well‑structured bundle with code‑splitting cuts first‑paint JS by more than half.

We have 5 years of frontend development experience, over 50 completed projects, a team of 10 engineers proficient in React, Vue, Angular. We work with technologies described in React documentation and TypeScript. Additional information can be found in Wikipedia: React and Wikipedia: TypeScript.

What Stack to Choose for Frontend Development with React?

We compare tools by real metrics. Next.js is 20‑30% faster in SSR builds than Nuxt with the same page size. TypeScript reduces production bugs by 60‑70% compared to JavaScript. Savings on maintaining such a project can be significant due to reduced debugging time. If you need a lightweight SPA with minimal cost, React + Vite is enough. For a content site with SEO, Next.js with ISR gives TTFB below 50 ms even with 50,000 pages.

Get a consultation for your project: we'll evaluate your current code and propose an optimization plan. Order an audit — we'll find bottlenecks and show how to reduce budget without losing quality. Contact us to start the discussion.