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.syncsyncs 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.
| Type | Complexity | Platforms | When to Use |
|---|---|---|---|
| Safari Web Extension (MV3) | Medium | Mac, iOS | Recommended for most cases |
| Safari App Extension | High | Mac | When native APIs needed |
| Content Blocker | Low | Mac, iOS | 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.
| Requirement | Description |
|---|---|
| Apple Developer Program | $99/year, mandatory subscription |
| Mac App Signing | Developer ID or Mac App Store |
| Entitlements | Enable Safari Extension |
| App Review | 1-7 days, may require resubmission |
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
Service Worker terminates
Use `chrome.storage.session` to store state—this prevents data loss on restart.CORS in Content Script
Redirect fetch through Background—this solves the problem.Extension doesn't appear on iOS
Ensure the wrapper app has been launched at least once, then enable the extension in Settings.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.