What is TTFB by device
TTFB by device shows the Time to First Byte (TTFB) value across different device types (e.g., Mobile or Desktop). This lens helps you identify which devices experience slower server response times or network delays.
The list shows only device types that generated traffic to your website during the selected period.
Common reasons for slower TTFB on certain devices include network conditions, device-specific DNS resolution delays, or cellular vs. Wi-Fi differences affecting backend latency.
TTFB is a key foundational metric measuring how quickly the server sends the first byte of data after a request is made.
Healthy TTFB by device sample
Should you worry
A healthy TTFB by device lens looks all green. Some devices may be greener than others, but as long as there's no yellow or red, it’s considered healthy. The greener the device, the faster the server response.
Unhealthy TTFB by device sample
In the example below, TTFB by device shows that Desktop is both the most popular and the slowest device type. This often results in higher bounce rates, more exits, and lower conversions.
Resolving unhealthy TTFB by device
Go-to action plan to resolve an unhealthy TTFB by device:
Ask Uxi to analyze your TTFB by device values and suggest improvements.
Use Filters to focus on the slow device in your TTFB by device, then review other TTFB lenses to identify backend or network bottlenecks affecting that device.
Simulate TTFB of the suspected lens to see if fixing it will resolve the TTFB by device. If yes, this is where the resolution focus should be.
Use an automated optimization tool like Navigation AI to improve your TTFB by device values.
Once you’ve improved TTFB, set an alert to be the first to know if it starts worsening again.
Try it yourself
Discover how your website performs with real user data.