Sites combine three layers: what you declare (UA), what you support (features), and what you measure (viewport).
Short answer
UA parsing gives a first guess In practice, open the linked tool below and compare your live values with the explanations that follow.
How it works
How Websites Detect Your Device comes down to reading documented browser signals and interpreting them honestly — including when the browser withholds them.
- UA parsing gives a first guess
- Feature detection confirms touch, WebGL and storage
- Responsive breakpoints react to viewport, not labels
At a glance
| Signal | What you learn |
|---|---|
| Browser report | Live values for this device right now |
| Withheld fields | Privacy protections, not hardware faults |
| Best next step | Use the related tool to verify your own setup |
Practical steps
- Open the related tool and note the highlighted rows.
- Compare them with the points above.
- If something looks off, check zoom, extensions and private mode, then retest.
Try it live: open the related checker and see your own values.
FAQ
Is that tracking?
Adaptation itself is not tracking. It becomes tracking only when combined with identifiers — which is why browsers generalize the inputs.
Related reading
Bottom line: Responsive breakpoints react to viewport, not labels When in doubt, trust the live tool over memory — browsers change, and support varies by browser.