OUI Scout

Offline MAC-address converter and OUI vendor lookup.

OUI Scout turns a pasted MAC address into the four formats network engineers actually use — Plain (`AABBCCDDEEFF`), Colon (`AA:BB:CC:DD:EE:FF`), Cisco-dot (`AABB.CCDD.EEFF`), and Hyphen (`AA-BB-CC-DD-EE-FF`) — and identifies the hardware vendor from its OUI prefix. Conversion and vendor lookup happen in a single paste, fully offline. The OUI database is bundled inside the extension, so there are no network requests, no host permissions, and no third-party services. A MAC address never leaves your machine. ## What it does - Paste any common MAC shape — colon, hyphen, dotted, space-grouped, or bare hex — and it is normalized instantly. - Shows all four output formats at once, each with one-click copy. - Resolves the hardware vendor by longest-prefix match against the bundled IEEE MA-L / MA-M / MA-S registries. - Shows a clear "Unknown vendor" state when a prefix is not in the database, and a clear error when the input is not a valid MAC address. - Follows your system light or dark appearance automatically. Keyboard accessible and screen-reader friendly. ## Privacy No data collection. No telemetry. No accounts. The extension requests zero permissions, makes zero network requests at runtime, and stores nothing. Your MAC addresses are processed locally in the popup and disappear when it closes. OUI data from the IEEE Registration Authority public listing.