The Network Information API is a web browser API that provides information about the device's network connection. It exposes properties like downlink speed (estimated bandwidth in Mbps), effective connection type (e.g., 4G, 3G, 2G), round-trip time (RTT), and whether data saver mode is enabled. This API helps web developers adapt their content delivery based on the user's network conditions, enabling better performance optimization and user experience.

The downlink speed provided by the Network Information API is an estimate based on recently observed network activity. It is not a precise measurement and can vary based on factors like network congestion, server load, and device limitations. The value represents the browser's best guess of the current effective bandwidth. For a more accurate measurement, use the Manual Speed Test feature on this page, which performs an actual download test. Note that the API estimate tends to be more conservative and may underreport actual speeds.

The Network Information API is primarily supported in Chromium-based browsers including Google Chrome, Microsoft Edge, Opera, and Samsung Internet (on mobile). As of 2024, Firefox has limited support (requires the dom.netinfo.enabled flag). Safari does not currently support this API. Mobile browsers generally provide more detailed information (such as connection type like 'cellular' or 'wifi') compared to desktop browsers. If the API is unavailable, this tool will display a warning and you can still use the manual speed test.

The effective connection type (effectiveType) is a simplified classification of the current network quality. It uses labels like slow-2g, 2g, 3g, and 4g to represent the overall network performance. These labels are determined by combining RTT and downlink values: slow-2g (RTT ≥ 2000ms, downlink ≤ 50 Kbps), 2g (RTT ≥ 1400ms, downlink ≤ 70 Kbps), 3g (RTT ≥ 270ms, downlink ≤ 700 Kbps), and 4g for anything better. This classification helps developers make broad decisions about content delivery strategies.

RTT (Round-Trip Time) is the time it takes for a data packet to travel from your device to a server and back again, measured in milliseconds (ms). Lower RTT means faster responsiveness — critical for real-time applications like video calls, online gaming, and web browsing. High RTT causes noticeable lag. Typical RTT values: Fiber/ broadband (1-50ms), 4G LTE (30-100ms), 3G (100-500ms), satellite (500-700ms). The RTT shown here is an estimate based on recent network observations.

To improve your network speed: 1) Move closer to your WiFi router or use a wired Ethernet connection. 2) Reduce the number of devices using the same network. 3) Close bandwidth-heavy background applications. 4) Restart your router and modem. 5) Update your router firmware and device network drivers. 6) Consider upgrading your internet plan or switching to a faster provider. 7) Use a mesh WiFi system for larger homes. 8) If on mobile, switch from cellular to WiFi when available, or move to an area with better signal.

Yes, when data saver mode (saveData) is enabled, the browser signals to websites that the user prefers reduced data usage. This is common on mobile devices with limited data plans. Websites that respect this flag may serve lower-resolution images, defer non-critical downloads, disable auto-playing videos, or reduce overall content weight. The saveData flag is a hint — it's up to each website to honor it. You can toggle this setting in your browser or device settings under data usage or network preferences.