Less of what you don't want. Nothing watched.
For adults blocking unwanted sexual content on their own iPhone: native Screen Time filtering in Safari plus shields for the apps or categories you choose — voluntary, private, and honest about its limits.
Direct App Store link · Free blocking · iPhone with iOS 17 or later
You choose the block. Nobody sees what you browse — not even your ally. They see that something happened, never what.
What changes on your phone
Turn on adult website filtering and Safari starts refusing known adult sites using Apple's own content filter — the same one built into iOS, applied through Open Book's setup instead of a maze of Settings screens. Separately, shield specific apps or whole categories (for example, browsers or social apps you have chosen to step away from) so opening one shows a calm blocked screen instead of the feed. Both run on-device through Screen Time. There is no VPN profile, no proxy, and no browsing data sent anywhere.
What stays the same
Everything else on your phone works as before. Open Book does not watch pages, log history, read messages, or take screenshots — it cannot show anyone what you visited, because that information never leaves your device.
Do it with a witness, or don't
Blocking alone is free and private. If you want support, invite up to five people you trust: they see protection-related event types and check-in status in a private portal, get optional text alerts that only say to look at the dashboard, and can approve a short pause when you ask for one. They join free with a web account. And it stays voluntary — remove an ally, delete your account, or revoke Screen Time permission whenever you decide, no approval needed. What allies can and cannot see.
An honest word about effectiveness
No iPhone blocker you control yourself is bypass-proof: anyone holding the phone can change Settings, and determined workarounds exist on every platform. What a witness changes is not the lock but the quietness — changes and missed check-ins can surface to someone who cares about you. Alerts need connectivity and background check-ins to arrive; a late or missing check-in does not prove anything changed. If that framing feels right, here is what the optional subscription costs. If you only want the filter, try Apple's built-in method first — it may be enough.
How blocking without a VPN differs
Many monitoring tools route your traffic through a VPN so they can record page titles for your ally to read. Open Book does the opposite: it enforces Apple's on-device filter and tells your ally nothing about content. Blocking without a VPN, explained.
On a desktop? Point your iPhone camera here to open Open Book on the App Store.