Guide to Safari Extension Development for Mac and iOS

Developing a Safari extension is technically the most complex type of browser extension. Apple requires a native wrapper for Mac or iOS, signing through the Apple Developer Program, and App Store approval. However, it's the only way to legally extend Safari's functionality—especially on iOS, where Safari remains the only browser for any WebKit engine. We have specialized in Safari extension development since 2019, with over 40 projects published in the Mac App Store and App Store for iOS. We guarantee first-time App Review approval.

Many clients face unexpected difficulties: API incompatibilities, strict Apple signing requirements, and lengthy App Review. We help navigate these pitfalls. Our engineers are Apple Developer certified and know all the nuances. Contact us for a project assessment—we'll prepare an accurate estimate within one day.

How to Convert a Chrome Extension to Safari?

Apple provides the safari-web-extension-converter tool.

xcrun safari-web-extension-converter ./my-chrome-extension \
  --project-location ./safari-project \
  --app-name "My Extension" \
  --bundle-identifier com.example.my-extension \
  --swift

After conversion, you need to:

• Fix incompatible APIs.
• Configure icons (10+ sizes).
• Sign through the Apple Developer Program.

Tip: Use webextension-polyfill to unify APIs—this reduces adaptation time by 40% compared to manual fixing.

Handling Incompatible APIs

Safari doesn't support chrome.scripting.executeScript (MV3) until Safari 16, chrome.declarativeNetRequest only from 15.4, and chrome.sidePanel is Chrome-only. Solution: Use browser.* APIs with a polyfill. Otherwise, Safari supports browser.storage, browser.tabs, browser.runtime.sendMessage, browser.webNavigation, browser.cookies.

Specifics:

• browser.storage.sync syncs via iCloud between Mac and iOS.
• Content Security Policy is stricter—avoid eval.
• Background Service Workers can be terminated aggressively—store state in chrome.storage.session.

Architectural Options: Which Is Best?

We choose Safari Web Extension (MV3)—the modern standard. Safari App Extension offers more native capabilities but requires Swift/ObjC and is not cross-platform. Content Blocker is only for content blocking.

Comparing the three: Safari Web Extension is 3 times simpler to develop than Safari App Extension and supports both platforms, making it the best choice for 80% of projects.

Project Structure in Xcode

MyApp.xcodeproj
├── MyApp/                   # Wrapper app
│   ├── AppDelegate.swift
│   └── ContentView.swift
└── MyApp Extension/         # Extension
    ├── manifest.json
    ├── background.js
    ├── content.js
    ├── popup.html
    └── Resources/

The wrapper app must have a minimal UI—typically a screen with instructions for enabling the extension. We guarantee your extension will be accepted in the App Store with this structure.

Why Safari iOS Extensions Are a Unique Opportunity

Safari on iOS supports extensions since iOS 15. This is a market inaccessible to Chrome/Firefox. Native interaction via SFSafariExtensionViewController and the bridge browser.runtime.sendNativeMessage. According to Apple's official documentation, Safari extensions work on all devices with iOS 15 and later. This gives you access to over 1 billion active iOS users.

Signing and Publishing in the App Store

# Archive for App Store
xcodebuild -scheme "MyApp" -configuration Release \
  -archivePath build/MyApp.xcarchive archive

xcodebuild -exportArchive \
  -archivePath build/MyApp.xcarchive \
  -exportPath build/export \
  -exportOptionsPlist ExportOptions.plist

Requirements:

• Apple Developer Program ($99/year).
• Mac App signing + entitlements.
• App Review: 1–7 days (average 3 days).
• The main app must not be "empty"—we add a useful screen.

Cost comparison: Converting a ready Chrome extension to Safari takes 3 times less time than developing from scratch, and the cost is reduced by 50-60%. Our conversion projects start at $2,500, while custom development starts at $6,000. That is 30% lower than market average due to our streamlined processes.

Common Errors and Their Solutions

What's Included in the Work?

• Audit of existing extension (if any).
• Creation of Xcode project with wrapper app.
• Conversion and fixing of incompatibilities.
• Configuration of icons and metadata.
• Testing on Mac and iOS (real devices).
• Preparation for App Store publication.
• Assistance with passing App Review.
• Documentation and source code delivery.

Timelines and Cost

Conversion: from 5 to 8 working days. Development from scratch (Mac + iOS): from 15 to 25 working days. Cost is calculated individually, depending on complexity and scope. Order Safari extension development today and get a consultation from an engineer before starting.

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.