Which app is using my internet in the background?

Background traffic is easy to miss because nothing on screen tells you about it. Pulse by Zaweba lists every app's network use on its Live page, so you can sort that column and see what is talking to the internet right now, and its History page ranks the biggest data users for today, yesterday or this week, including the hours when you weren't looking.

The usual suspects are updaters, cloud storage clients, game launchers and browsers with many tabs. Knowing which one it is, rather than guessing, saves a lot of uninstalling and reinstalling.

Signs that something is using the connection

You might notice video buffering when nobody else is online, a slow game, or a data allowance running down faster than it should. On a capped or metered connection that last one costs real money. The trouble is that the program responsible may have no window open at all. It might sit in the notification area or run as a set of helper processes with names that mean nothing to you.

Pulse groups all the processes of one program into a single row with its icon and a friendly name read from the program file. A browser with dozens of processes becomes one line. That alone makes background activity much easier to spot.

Checking what is busy at this moment

Open Pulse and go to the Live page (Ctrl+1). Click the network heading to sort it, biggest first. The Network graph across the top shows the total for the whole PC, with download and upload rates, so you can see whether there is much traffic at all.

By default Windows only lets a normal user see each app's data from its own usage records, so the column reads "Data today" and lags about a minute. That is fine for finding a steady background user. If you want each app's traffic counted live, use "Allow live per-app network" in Settings. It adds your account to Windows' Performance Log Users group once, after an administrator prompt and a sign-out, and from then on the figures move in real time. The note bar above the table says which mode you are in.

Catching it after the event

Background traffic often happens in bursts: overnight backups, updates while you are at lunch, a sync that starts as soon as you log in. The live view can't show something that has already stopped, which is why Pulse keeps history. It records every minute for 30 days by default.

Open the History page (Ctrl+3), choose Today, Yesterday or This week, and look at Top bandwidth users. It ranks apps by data used over the period. Pulse also stores Windows' hourly per-app usage records, so this list works even without live counting. The network graph on the same page shows when the traffic happened, which often explains it: a spike at the same time each night looks a lot like a scheduled job.

Deciding what to do next

When you have a name, you can act. If you don't recognise the program, select it and choose Open file location to see where it is installed; the folder usually makes it obvious which product it belongs to. If it should not be running, End task closes every process of that app after a confirmation. For the longer term, check the program's own settings for automatic updates or sync, and consider the Alerts page option that warns you when one app uses more than a set amount of data in a day.

Pulse itself stays light and quiet. It runs in the tray, uses about 0.1 per cent CPU in the background on the test PC, and sends nothing anywhere, so it won't add to the traffic you are trying to track down.