How to Audit Whether a Clipboard App Talks to the Network

To check whether a clipboard app sends anything over the network, watch its connections in Resource Monitor while you copy a few test strings, then block it with a Windows Defender Firewall outbound rule and confirm that history and paste still work. A local-only app should open no new connection when you copy, and should keep working with its network access blocked. Both tests use tools built into Windows and take about 15 minutes.

This won't show you what's inside encrypted traffic, but it reliably answers the main question: does the app connect somewhere every time you copy?

Before you start

1. Turn off Windows' own clipboard sync so it doesn't confuse the results: Settings > System > Clipboard > Clipboard history across your devices off. How to disable Windows clipboard cloud sync has the details.
2. Close other clipboard managers, Phone Link and anything else that might react to copies.
3. Let the app you're testing finish any first-run update or download.
4. Find its program file: in Task Manager > Details, right-click the process and choose Open file location. Note the full path and the app's version number.

Some apps, including Electron apps, run several processes with the same file name. Watch all of them.

Test 1: Watch connections while you copy

1. Press Windows logo key + R, type resmon and press Enter to open Resource Monitor.
2. Open the Network tab and tick the app's process in Processes with Network Activity. This filters the other panes to that app.
3. Expand Network Activity and TCP Connections.
4. In Notepad, copy ten different strings, including a made-up token such as audit-test-not-a-real-token.
5. Watch for a minute.

Pass: no new remote addresses appear when you copy.

Look closer: a new connection appears at the moment of each copy. Treat that as a possible upload of your clips until the vendor explains it.

If the process never shows up in Processes with Network Activity, it isn't using the network right now, which is a good sign.

For a quick snapshot from PowerShell, list the app's TCP connections by process. Replace copyq with the process name you noted, without .exe:

Get-NetTCPConnection -OwningProcess (Get-Process copyq).Id -ErrorAction SilentlyContinue |
  Select-Object RemoteAddress, RemotePort, State

No output means the app has no TCP connections open. Microsoft's free Sysinternals tool TCPView shows the same information live, with the owning process for each connection.

Test 2: Block the app and see what breaks

1. Press Windows logo key + R, type wf.msc and press Enter to open Windows Defender Firewall with Advanced Security.
2. Select Outbound Rules, then New Rule.
3. Choose Program, then browse to the app's program file.
4. Choose Block the connection, keep all profiles ticked, and give the rule a clear name such as "Block clipboard app (test)".
5. Restart the app, then copy and paste as usual.

You can create the same rule from an administrator PowerShell window. Replace the path with the one you noted:

New-NetFirewallRule -DisplayName "Block clipboard app (test)" -Direction Outbound -Action Block -Program "C:\Path\To\App.exe"

Pass: history, search and paste all keep working. Only update checks or sign-in should fail.

Fail: the app won't start, history won't load, or new copies stop appearing. It depends on the network for its core job, so it isn't local-only.

Delete the rule when you're done (Remove-NetFirewallRule -DisplayName "Block clipboard app (test)"), or keep it if you're happy to update the app manually.

Test 3: If the app has an account

1. Sign in on this PC only.
2. Copy a unique string, such as audit-cloud-test-1.
3. Check the vendor's website, phone app or a second PC for that string, then check again a day later in case uploads are batched.

If it appears anywhere else, your clips left the PC. That's expected for a sync product such as ClipboardFusion Pro with syncing on. It's a red flag for anything sold as local-only.

How to read the results

An update check sends no clipboard data, so it doesn't make an app any less local. A good app documents it and lets you turn it off.

What some popular tools document

• CopyQ states that it "does not send anything over network".
• Ditto lists no login, no cloud and no telemetry. The network feature its privacy policy describes is Friends, which sends clips to computers you list on your local network.
• ClipboardFusion keeps history locally on the Free plan. Syncing clips to other computers is a Pro feature, so expect traffic when it's on.
• Edge Drop has no telemetry and no sync. The GitHub build checks GitHub for updates about 3 seconds after launch when Automatic updates is set to Automatic or Notify me, and makes no automatic requests when it's set to Off. The Microsoft Store build makes no update requests. The only other request happens if you drag a web image onto the shelf and the browser passes only its address. How Edge Drop updates on GitHub builds covers the update modes.

Use those statements as the thing you're testing, not as the result.

What this audit can't catch

• What's inside encrypted (HTTPS) traffic. You can see where the app connects, not what it sends.
• Uploads delayed beyond your watch window. Repeat Test 1 later, or leave the firewall rule in place.
• Helper processes with a different file name. Check every process the app starts in Task Manager.
• Clipboard reads by other software, such as malware. Can other apps read everything you copy? covers that.

Repeat the audit after major updates, and keep a one-line note of the date, version and result.

FAQ

Is an update check a privacy problem?

Not usually. It tells the vendor or GitHub that a copy of the app is running and from which IP address, but sends no clip data. Turn it off if the app allows it and update manually.

Do I need Wireshark for this?

No. Resource Monitor and a firewall rule answer whether an app connects when you copy. A packet capture adds detail, but it can't read encrypted traffic either.

What if the app is from the Microsoft Store?

Test 1 works the same way, because Store apps appear in Resource Monitor like any other process. Firewall rules for Store-packaged apps can behave differently from rules for ordinary programs, so if a program-path block seems to have no effect, rely on Test 1 and the vendor's own documentation.

Related reading

• What Does Local-First Mean for a Clipboard Manager?
• How to Check If a Windows App Has Telemetry
• How to Check an Electron App's Security Settings (IPC)
• Local-Only Clipboard Managers for Windows 11 (No Sync)

Sources

• Windows Firewall (Microsoft Learn) — outbound rules for programs.
• TCPView (Microsoft Sysinternals) — live view of connections by process.
• CopyQ security (CopyQ docs) — no network use.
• Ditto privacy policy (GitHub wiki) — the Friends feature is its only network use.
• ClipboardFusion compare (Binary Fortress) — syncing is a Pro feature.
• Using the clipboard (Microsoft Support) — Windows clipboard sync setting.

Copy. Stack. Drop.

Transform your clipboard into an interactive edge shelf. Stack, pin, and drag assets into any app with zero friction.

Download for Windows Get from Microsoft Store

How to Install Guide · First 10 Minutes Guide · Drag & Drop Guide · Edge Drop vs Win+V · Support