Connection Info — Network Type, Downlink, RTT

A coarse classification (slow-2g, 2g, 3g, 4g) the browser computes from recent network performance — not your literal radio type. A 5G connection in a poor-coverage area can be flagged 4g; a strong Wi-Fi over fibre is typically 4g (the highest class). Sites use this to adapt — heavy media for 4g, lite versions for 2g/3g.

Different measurements. Our connection-info reads the browser's running estimate, which is updated by the browser based on recent traffic. The internet speed test runs an actual large download. The estimate can lag behind reality (especially after switching networks) and tends to be conservative. Use both for context.

Browsers cap reported downlink to protect your privacy — Chrome rounds to the nearest 25 Mbps and caps display at certain thresholds. The actual capability is higher; the API just doesn't reveal precise speeds. Run our internet speed test for a real number.

The Network Information API is a Chromium feature (Chrome, Edge, Opera, Brave). Safari and Firefox refuse to implement it for privacy reasons (network type can identify users). On those browsers, only the device's network state — online/offline and basic 'metered' hints — is available.

Round-trip time. The estimated milliseconds for a tiny packet to reach a server and come back. Low RTT (under 50 ms) means responsive apps; high RTT (200+ ms) means even loading a fast page feels slow because every request adds latency. Bad RTT often comes from satellite ISPs, double-NAT setups, or congested cellular cells.

When users enable 'Lite mode' or 'Data Saver' in their phone settings, the browser sets navigator.connection.saveData = true. Sites should respond by serving smaller images, deferring autoplay video, etc. Even if a site has a fast connection, respecting saveData reduces user data costs and usually speeds up loads on cellular.