the registry
Every client hint, with your live values
The Your browser column is not documentation, it is a live reading. HTTP means the value arrived as a request header on this page load. JS API means your browser did not send the header but exposes the same value to JavaScript. Everything else is data your browser is keeping to itself.
User-agent hints, sent by default
Low-entropy hints every Chromium browser volunteers on every request, no opt-in needed. Together they reveal roughly what a shop window reveals about a store: browser, major version, platform, mobile or not.
| Hint | Example | Opt-in | Your browser |
|---|---|---|---|
| Sec-CH-UA | "Chromium";v="126", "Not/A)Brand";v="8", "Google Chrome";v="126" | default | … |
| Sec-CH-UA-Mobile | ?0 | default | … |
| Sec-CH-UA-Platform | "Linux" | default | … |
User-agent hints, on request
High-entropy hints the browser only attaches after your server opts in with Accept-CH. They carry real fingerprinting surface (CPU architecture, exact versions, device model), which is exactly why they are off by default.
| Hint | Example | Opt-in | Your browser |
|---|---|---|---|
| Sec-CH-UA-Arch | "x86" | Accept-CH | … |
| Sec-CH-UA-Bitness | "64" | Accept-CH | … |
| Sec-CH-UA-Full-Version-List | "Chromium";v="126.0.6478.127", "Google Chrome";v="126.0.6478.127", "Not/A)Brand";v="8.0.0.0" | Accept-CH | … |
| Sec-CH-UA-Full-Version deprecated | "126.0.6478.127" | Accept-CH | … |
| Sec-CH-UA-Model | "Pixel 8" | Accept-CH | … |
| Sec-CH-UA-Platform-Version | "14.0.0" | Accept-CH | … |
| Sec-CH-UA-WoW64 | ?0 | Accept-CH | … |
| Sec-CH-UA-Form-Factors experimental | "Desktop" | Accept-CH | … |
User preference hints
Media-feature preferences promoted to request headers, so the very first HTML response can honor dark mode or reduced motion without a flash of the wrong theme.
| Hint | Example | Opt-in | Your browser |
|---|---|---|---|
| Sec-CH-Prefers-Color-Scheme | dark | Accept-CH | … |
| Sec-CH-Prefers-Reduced-Motion | reduce | Accept-CH | … |
| Sec-CH-Prefers-Reduced-Transparency experimental | no-preference | Accept-CH | … |
Device hints
Screen and hardware characteristics for responsive image and asset selection on the server. Each modern Sec-CH-* name supersedes an older unprefixed header from the 2015 draft.
| Hint | Example | Opt-in | Your browser |
|---|---|---|---|
| Sec-CH-DPR | 2 | Accept-CH | … |
| Sec-CH-Device-Memory | 8 | Accept-CH | … |
| Sec-CH-Viewport-Width | 1920 | Accept-CH | … |
| Sec-CH-Width | 780 | Accept-CH | … |
Network hints
Connection quality as the browser estimates it. Useful for serving lighter payloads on slow links, and the only group where one hint, Save-Data, is sent without any opt-in.
Wondering why the opt-in column matters, or how Accept-CH actually negotiates? Start with What are Client Hints? and the Accept-CH deep dive.