How to see which apps are using the internet on your Mac, and check that an app sends nothing
Open Activity Monitor (in Applications › Utilities), click Network and sort by Sent Bytes: every app and process that has used the network since the Mac started is listed, with how much it sent and received. To check one app, watch its row while you use it. The firewall built into macOS controls only incoming connections; it doesn’t stop an app from sending data out.
Activity Monitor, step by step
- Open Activity Monitor: press ⌘Space, type “Activity Monitor” and press Return.
- Click the Network tab at the top of the window.
- Choose View › All Processes to include background ones.
- Click the Sent Bytes column to sort by it; click again to put the largest first. Rcvd Bytes shows what each one downloaded.
- Type an app’s name in the search field to show only its row.
The counts add up from the moment the Mac starts, so a browser or a cloud-sync app near the top is normal. What matters is an app sending a lot when it has no reason to.
Check that one app sends nothing
- Find the app in the Network tab and note its Sent Bytes.
- Use it for a minute the way you normally would: dictate a paragraph, translate a page, take a few screenshots.
- Look again. A few kilobytes now and then is usually an update check. Hundreds of kilobytes or more while you work means your words, audio or images are going somewhere.
- Then try the simplest test of all: turn off Wi-Fi and use the app again. If it still does the job, it doesn’t need a server for it.
What the macOS firewall does, and doesn’t
System Settings › Network › Firewall blocks other computers from connecting to your Mac, and its options include Block all incoming connections and Stealth Mode, which keeps the Mac from answering probes. It doesn’t look at what apps send out. macOS has no built-in switch to cut a single app off from the internet; for that you need a separate network-filter app. While you’re in System Settings, two permissions under Privacy & Security are worth a look: Local Network (which apps may find devices on your home network) and Screen & System Audio Recording.
What our apps connect to
Our apps do their work on the Mac, so they should barely register in the Network tab while you use them. Here is everything each one may connect to, and when.
| App | Connects for | Never sends |
|---|---|---|
| Volna | Downloading the speech model once; update checks | Audio, text, your vocabulary |
| Kalila | Downloading each language once; update checks | What you translate, your history, your phrasebook |
| SimpleShot | Update checks; a time proof (only the image’s fingerprint) or a link, when you ask for one | Captures you don’t share |
| Seekframe | Update checks (the App Store edition has no network access at all) | Photos, videos, searches |
| Textbound | Update checks, in the version from its site | Messages, contacts, exports |
None of them has analytics or an account. Don’t take our word for it: the steps above take two minutes.
Questions
Why is my Mac using the network when I’m not doing anything?
macOS syncs iCloud, checks for updates, refreshes mail and fetches suggestions in the background. In the Network tab, processes with system-sounding names are usually macOS itself; only quit apps you recognise.
Can I block an app from the internet on a Mac without extra software?
Not for outgoing connections. The built-in firewall controls incoming ones only. You can quit the app, turn off Wi-Fi while you use it, or install a network-filter app that asks before each new connection.
How do I see how much data an app used?
Activity Monitor’s Network tab shows Sent Bytes and Rcvd Bytes for each process since the Mac last started. Restart, use the app, and the numbers cover just that session.
Is an app that works offline always private?
Not always: it could store your data and send it later. Watch its Sent Bytes after you reconnect, and read what its privacy policy says it sends.