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Localhost and developer tools

On Mac, Crest automatically shows its developer toolbar for local development addresses. This includes localhost, loopback and private-network addresses, single-label hosts, common local suffixes such as .local and .test, and file URLs.

Use Shift-Command-I to show or hide the toolbar on any website.

Preview a different viewport​

Choose a phone or desktop preset, or enter a custom size, in the developer toolbar. The live page renders within that viewport so you can review responsive layouts without resizing your whole browser window. Return to the normal viewport when finished.

This previews the page’s layout at the chosen dimensions; it does not reproduce another device’s hardware or browser engine.

Toolbar controls​

  • Edit the complete development URL without losing the visible route.
  • Copy the current link.
  • Open Site Settings and inspect permissions.
  • Use Capture in Portrait Mode, Copy Full Page Capture, or drag a region to copy it.
  • Toggle the inspector's Console, Network panel, or element inspection.

Automatic localhost tools follow the focused address. The manual toolbar toggle lets you inspect other sites too.

Open the inspector directly​

Use Option-Command-I, the menu, or the command palette. A Chromium page opens Chromium DevTools in the window, and a WebKit page opens Web Inspector. The inspector follows the focused page, including the focused card inside Split View.

Security boundary​

Developer tools make page internals visible and can change runtime state. Use them only for sites and code you trust. A certificate warning, external-app request, or protected permission remains subject to Crest’s normal navigation and site-permission policies; localhost mode does not bypass those checks.