How To Monitor Network Activity On Mac

If your internet suddenly feels sluggish, or a Zoom call starts buffering, the problem might not be your router. Very often, a hidden app or background process on your Mac decides to download a massive update right in the middle of your workday.

If you want to stop the bandwidth drain, you need to find out exactly which app is using the network. Here is how to monitor your internet activity and track down the culprit.

Using Activity Monitor to Check Network Usage

macOS has a built-in tool that tracks every single byte of data sent and received by your computer.

1. Press Cmd + Space to open Spotlight Search.
2. Type "Activity Monitor" and hit Enter.
3. Click the Network tab at the top of the window.

You will see a live list of every process currently interacting with the internet.

How to Read the Network Data

The Network tab has several columns, but the two most important ones are:

• Sent Bytes: Data uploaded from your Mac to the internet (like sending an email or syncing a file to iCloud).
• Rcvd Bytes: Data downloaded from the internet to your Mac (like streaming a video or downloading an update).

If your internet feels slow, click the Rcvd Bytes column to sort the list from highest to lowest. The app at the top is the one eating all your bandwidth.

Common Network Hogs

When you look at the top of the list, you might see familiar apps like Chrome, Spotify, or Dropbox. If they are downloading huge amounts of data, you can simply close the app to instantly free up your bandwidth.

But you will also see cryptic system processes.

For example, if you see nsurlsessiond downloading gigabytes of data, your Mac is likely downloading a background macOS software update or syncing massive files from iCloud Drive. We explain this specific process in detail in our guide on What is nsurlsessiond?.

If you see trustd sending a few kilobytes of data, that is just macOS checking digital security certificates. You can read more about it in our guide on What is trustd?.

A Better Way to Monitor Your Network

Activity Monitor is a great diagnostic tool, but it is terrible for continuous monitoring. You only know to open Activity Monitor after your internet is already slow.

If you want real-time visibility into your upload and download speeds, you need MacStats.

MacStats is a native menu bar app that displays your live network speeds directly at the top of your screen. You can instantly see if a massive download kicks off in the background without having to open any extra windows.

Even better, if you see a huge spike in network activity and you do not know what is causing it, MacStats has an AI Process Explainer. Just click the active process in the MacStats menu, and the AI will translate the confusing system name into a plain English explanation of exactly what it is doing.

Stop wondering where your bandwidth went. Download MacStats for Free and get total visibility into your network activity. See our full breakdown in MacStats vs Activity Monitor.