UA Intercept by sizzlor

UA Intercept does one thing well: it changes your User-Agent.

Not a generic header editor — a User-Agent switcher with named profiles, a preset picker, and a spoof depth you choose.

• Profiles — create, edit, duplicate, and delete named User-Agent profiles; one active at a time, switchable from the toolbar popup.
• UA tokens — build a User-Agent from tokens you can enable individually and either append to your real User-Agent or replace it outright.
• Selectable spoof depth — Headers only changes just the User-Agent request header the server sees. Full also sets matching sec-ch-ua* Client Hints and rewrites navigator.userAgent, navigator.platform, navigator.userAgentData, navigator.appVersion, and navigator.vendor so page JavaScript sees the override too.
• Preset picker — Windows/macOS/Android Chrome, macOS/iOS/iPadOS Safari, Linux Firefox, Googlebot, or a fully custom User-Agent.
• Import / export — versioned JSON of your own, plus best-effort import of ModHeader exports (every User-Agent row, enabled or disabled, with its URL filters).
• Per-profile URL filters — scope a profile to, or away from, specific domains.
• 20 languages with RTL support, a toolbar badge while active, and a keyboard-operable, screen-reader-labeled UI.

No data collection, no telemetry, no ads, no account. Profiles never leave your device. The only network request is an opt-in, off-by-default update check against GitHub's public Releases API, which sends none of your data.


This is not a stealth tool — full spoof defeats casual User-Agent sniffing, not a determined fingerprinter. Web Workers are not covered by the full spoof, and the override is detectable by page JavaScript.

Open source (MIT): https://github.com/sizzlorox/ua-intercept