Is your porn blocker watching you? How on device blocking works
Handing a blocker access to your screen is a big ask, and the fair question is where your browsing goes. For address checks in Blockerflow, the answer is that it goes nowhere.
Two ways a blocker can check a site
Some blockers send every address you visit to a server, which answers allowed or blocked. That is easy to build, and it means a company has a log of your browsing. Others ship the blocklist inside the app and compare on the phone, so there is nothing to send and nothing to log.
Blockerflow does the second. About 1.1 million adult domains are bundled in the app, and each address is compared against them on your device before the page loads.
What stays on your phone
Addresses read from your browser stay on the device. So does the on screen content the app inspects to recognise a Reels or Shorts feed, which is examined in memory and never stored. Your blocklist, allowlist and settings are kept locally.
There is no analytics library, no crash reporter and no telemetry upload path in the app, so there is no background channel quietly reporting what you did.
What can leave your phone, and only if you choose it
Three optional features use a server, and each one is off until you turn it on. The AI Coach sends the reason you type plus the name of the feature you are trying to disable, and a server passes it to Google Gemini for an approve or reject answer. Choosing a friend as your partner means their email address is sent so the server can email them a PIN. Signing in stores your account and synced settings in the cloud.
None of these carry your browsing history. If you want none of it, you can use the blocker fully signed out with Myself or Time Delay as your partner, and nothing leaves the phone at all.
Why on device is better for blocking, not just for privacy
A local comparison is fast enough to stop a page before it loads, where a server round trip would show you the thing you asked not to see. It also keeps working with no connection, on a train or in a dead spot, where a cloud filter quietly fails open.
Deleting what you did share
Settings keeps the two kinds of deletion separate, because they are genuinely different. Factory Reset wipes what stayed on the device: your settings, lists and partner choice. Delete Account removes the cloud side, your account and the settings synced to it. Neither one implies the other, and both run your accountability check first.
Frequently asked questions
Can Blockerflow see which sites I visit?
Addresses are checked on your phone and are not uploaded. There is no analytics or telemetry reporting your browsing.
Does the blocker need the internet to work?
No. The blocklist is inside the app, so checks work offline. Only the optional account, AI Coach and friend email features need a connection.
Can I use it without an account?
Yes. Signing in only syncs settings. Pick Myself or Time Delay as your partner and the app works fully offline.
How do I delete my data?
Factory Reset in Settings erases what is on the device. Delete Account removes your account and anything synced to the cloud.
Try Blockerflow
Block adult content and distracting feeds on Android, with an accountability system behind it.