Extension compatibility and known limitations
Install most standards-based Chrome extensions directly from their Chrome Web Store pages. Compatibility varies where an extension depends on Chrome-only APIs or a native companion.
Crest measures package verification, installation, and runtime startup separately from complete workflow support. A package can load cleanly while an optional feature still needs an API WebKit does not implement.
What Crest supports
- A native permission and compatibility review for signed CRX3 packages from the Chrome Web Store.
- Per-Space and per-device installation, storage, enablement, permissions, website access, and pinning.
- WebExtension action popups, options pages, and keyboard commands where their APIs are available in WebKit.
- Plain-language Running, Needs attention, Off, and blocked states, with JavaScript errors collapsed under Technical Details.
- Load Unpacked… for development and manual testing, without native-messaging access.
- Discovery of ordinary WebExtension resources inside signed Safari apps, without treating Safari native handlers as portable.
See Direct build, App Store, and native companions for the distribution boundary.
Signed-package audit
Validated on August 10, 2026:
| Extension | Version | Startup result | Measured boundary |
|---|---|---|---|
| Dark Reader | 4.9.129 | Loads cleanly | No startup error observed. |
| uBlock Origin Lite | 2026.804.1652 | Loads cleanly | Declarative Net Request package loaded without a startup error. |
| 1Password | 8.12.30.21 | Loads cleanly | Running, setup UI, sign-in navigation, and BrowserSupport launch verified. Trusted-browser authorization and autofill were not completed. |
| SponsorBlock | 6.1.6 | Loads cleanly | No manifest or startup runtime error observed. |
| Bitwarden | 2026.7.0 | Partial / experimental | Notification-click handling is unsupported. |
| Grammarly | 14.1318.0 | Partial / experimental | Managed storage, cookie, and telemetry limits are reported. |
| React Developer Tools | 7.0.1 | Partial / experimental | Isolated execution world is unsupported. |
| Tampermonkey | 5.5.0 | Partial / experimental | WebKit rejects tabs.onUpdated startup registration. |
| iCloud Passwords | 3.3.0 | Partial / experimental | It installs and loads, but Apple's Chrome-specific companion behavior is not claimed as fully functional. |
“Loads cleanly” covers verification, installation, WebKit context load, and initial background startup. It does not certify every site, account, popup, update, native-companion authorization, or optional feature.
1Password's measured boundary
The Chrome Web Store package installed as Running, rendered its setup interface, opened my.1password.com in a normal Crest tab, and caused Crest Direct to launch /Applications/1Password.app/Contents/MacOS/1Password-BrowserSupport.
The user must still add Crest as an additional trusted browser inside 1Password before desktop unlock and autofill can be expected. That final authorization and autofill workflow was not completed during validation. Follow Set up 1Password in Crest.
Safari-only formats
Safari content blockers and legacy Safari App Extensions are not WebExtensions and are not supported.
wBlock
wBlock is a hybrid. Its toolbar and userscript portion use Safari Web Extensions, but its primary blocker uses five Safari-only content-blocker extensions. Crest cannot reproduce the core wBlock blocking behavior and does not market wBlock as fully supported.
If an installed extension reports an error or a feature does not respond, continue with Troubleshoot partial compatibility.