Your browser describes itself to websites in two ways. The older one is the user agent string, a single line of text sent with every request and readable by scripts. The newer one is User-Agent Client Hints, a structured set of values that Chromium-based browsers provide, some by default and some only on request. This user agent checker shows both side by side and checks that they tell the same story.
What the checker shows
| Row | Source | What it means |
|---|---|---|
| User agent | navigator.userAgent |
The full user agent string |
| Brands | navigator.userAgentData.brands |
Browser brands and major versions |
| Platform | platform, plus platformVersion, architecture and bitness |
Operating system, its version and the processor type |
| Mobile | navigator.userAgentData.mobile |
Whether the browser presents itself as mobile |
| Full versions | fullVersionList |
Brands with their complete version numbers |
| Version match | User agent vs brands | The Chrome major version in both places |
| Platform match | User agent vs platform |
The operating system in both places |
Safari and Firefox don't support client hints. In those browsers the checker shows the user agent string and a note that client hints aren't available, which is normal.
Reading the user agent string
A desktop Chrome user agent today looks like this:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/152.0.0.0 Safari/537.36
Most of it is historical. The parts that matter are the platform in parentheses and the Chrome/ version. Chrome's User-Agent Reduction froze several details:
- The minor version is always
0.0.0. Only the major version, such as 152, is real. - The Windows part is always
Windows NT 10.0; Win64; x64, on Windows 10 and Windows 11 alike. - The Mac part is always
Macintosh; Intel Mac OS X 10_15_7, whatever macOS version you run and even on Apple Silicon.
Other Chromium-based browsers add their own token to the end, for example Edg/ for Microsoft Edge and OPR/ for Opera.
Reading the client hints
User-Agent Client Hints split the same information into fields. Three are low-entropy and available to every page: the brand list, the mobile flag and the platform name. The rest are high-entropy and returned only when a script asks for them with getHighEntropyValues(), or when a server asks for them in headers. This checker requests platform version, architecture, bitness, model and the full version list.
Two details often confuse people:
- The fake brand. The brand list includes an entry such as
Not.A/Brand. The client hints specification requires browsers to include an arbitrary value among the brands, in a changing order, so websites don't hard-code exact brand strings. It is expected. - Real versions. Because the user agent string is frozen, the client hints carry the real details.
fullVersionListshows the complete build number, andplatformVersionshows the real operating system version.
How the two should match
| Detail | In the user agent | In the client hints | Consistent when |
|---|---|---|---|
| Operating system | Windows NT, Macintosh, X11; Linux |
platform: Windows, macOS, Linux |
Both name the same system |
| Major version | Chrome/152.0.0.0 |
Chromium or Google Chrome brand: 152 | The numbers are equal |
| Full version | Always .0.0.0 |
Full build number | Expected to differ; not a mismatch |
| Windows version | Always Windows NT 10.0 |
platformVersion |
Windows 11 reports 13.0.0 or higher; Windows 10 reports 1.0.0 to 10.0.0 |
| macOS version | Always 10_15_7 |
platformVersion |
The hint shows the real macOS version |
| Processor | x64 on Windows, Intel on Mac |
architecture, bitness |
On Apple Silicon the hint can say arm while the string still says Intel |
| Mobile | No Mobile token on desktop |
mobile: false |
Both say desktop |
The Windows mapping comes from Microsoft's documentation, which notes that user agent strings won't be updated to tell Windows 11 from Windows 10.
The checker turns a row red in two cases: the user agent and the client hints report different Chrome major versions, or they name different operating systems. Both are contradictions a real, unmodified browser doesn't produce.
Common mismatches and their causes
- User agent switcher extensions. Many change the string but not the client hints, so the string says one thing and the hints another.
- Device emulation in developer tools. Emulating a phone changes the user agent and, depending on settings, the client hints. Turn it off before you test.
- A hand-typed user agent. Copying a user agent from another browser version gives a string whose version no longer matches the brands.
- Mixed brands. A string that ends in
Edg/should come with a Microsoft Edge brand in the hints. A brand list without it, next to an Edge string, is a contradiction.
The simplest fix is usually to stop changing the user agent by hand and let the browser report its own.
User agents in Multime
In Multime, each profile reports one coherent identity:
- Operating system shown to websites: Windows, macOS or Linux, with a version.
- Browser brand: Chrome, Edge, Opera or Vivaldi.
- User agent: set automatically to match the engine, which is Chrome 152 on Mac and Chrome 150 on Windows.
We recommend leaving the user agent on automatic. A user agent that names a version the engine isn't running creates exactly the version mismatch this checker flags. Open this page inside a profile after you choose its operating system and brand, and check that both match rows are green. Multime runs on Apple Silicon Macs with macOS 13 or later and on 64-bit Windows 10 and 11. There are no Android or iOS profiles.