How it works, explained
How On Guard works, one page per question.
The walkthrough shows it. These four pages say it plainly: where detection runs, what a detection does, why accountability needs no screenshots, and exactly what your ally receives.
A known adult site opens, your ally knows. He learns the app, the device and the time, never the site.
4 guides · Checked September 17, 2026 against the shipping app
What stays on your device, and what leaves it
Your device
What is on your screen
Frames are sampled as you scroll and browse.
On Guard, on your device
Classifies each frame locally, then lets it go.
A verdict
Clean, suggestive, or explicit. The frame is discarded.
Crosses the boundary
- A liveness heartbeat
- A detection event, with no content
- Your account, settings, and billing
- One screenshot, only if you send it
Never crosses it
- Any other screenshot or frame
- URLs or browsing history
- What you were looking at
- 01
What on-device detection means
The engine runs on your Mac, Windows PC, or Android phone. It looks at what is on your screen, decides clean, suggestive, or explicit, and throws the frame away. What crosses to the internet is a heartbeat, an event, and your account. Never the picture, unless you choose to send one screenshot after a false alarm.
4 min read
- 02
What happens on a detection
Explicit content gets a gate on your screen and a way to move on. A known adult site also sends one check-in text to your ally. Suggestive content gets a nudge and nothing more. Clean content gets nothing. Here is each, in order, using the real screens.
4 min read
- 03
Why accountability needs no screenshots
Screenshot accountability captures your screen, uploads it, and gives someone a feed to review. On Guard looks at your screen on the device, in memory, discards the frame, and sends one text that says it happened. No frame is saved or uploaded unless you choose to send us one screenshot after a false alarm, and that one never reaches your ally. We think that is the safer model and the more human one. Here is the reasoning.
4 min read
- 04
What your ally receives, and does not
One short text when a known adult site is opened on your device, with the app, the device and the time. A text if On Guard is uninstalled, signed out or a device is retired. A text if a device has not been active for 7 days. Never the site, the image, your history, or anything the guard saw on screen. Here it is, word for word.
3 min read
Prefer to see it? The walkthrough runs detect, redirect, the gate and the text: Watch it work.
Questions answered
Is this the same as the how-it-works page?
No. That page is a walkthrough you scroll. These four pages are the plain-text answers behind it, one question each, so you can read or share exactly the part you need.
What is the shortest honest summary?
Detection runs on your device. Explicit content gets a gate and a way out; a known adult site also sends one check-in text to your ally. Suggestive content gets a nudge to move on. No screenshots are kept or sent unless you choose to send one after a false alarm, and your ally learns the app, the device and the time, never the site or the image.
What about iPhone?
On iPhone and iPad, On Guard runs no detection of its own; it works through Apple's Screen Time controls. The ally check-in, account, and settings are the same everywhere.