Coming
AndroidA calm barrier between you and the impulse
Bastion is a simple Android tool that removes the easy access to porn. It is built on one principle: your data must never leave your phone.
It is not a miracle cure. But it gives you the seconds back — enough time to make a different choice than the impulse would have made for you.
Android only for now. iPhone does allow DNS filtering, but nothing that stops the app simply being deleted — and that is the part that matters. More on this below. In the meantime, Apple’s built-in Screen Time is the nearest alternative.
In development · last updated July 2026
When it’s ready
Bastion isn’t ready to download yet. When it is, you’ll be able to scan a QR code here and install it straight from this page — no account, no waiting list, no email.
How it is designed
Runs locally on your phone
All filtering happens on the device itself. Nothing gets sent away, because there is no server to send it to. Your behaviour is yours alone.
No account, no cloud
No sign-up, no login, no email to hand over. Bastion works even when you are offline, and there is no profile for anyone to look into.
A keyword filter you control
Blocks explicit content based on a local list of keywords. The list lives on your phone, and you can extend it yourself so the filter fits you.
PIN lock for weak moments
Protect the settings behind a PIN, so turning the filter off requires a deliberate choice. An extra hurdle exactly where you need one.
Why it is built this way
It never watches you
The best-known apps in this category work by watching. One takes a screenshot of your screen roughly every minute, blurs it, and uploads it to its own servers for someone else to review. Courts in at least five US states have used that same app to monitor people awaiting trial.
Bastion has nowhere in its code that records which sites were blocked. Not a setting you can turn on, not a log kept just in case — nowhere. That is a constraint the code is held to, and once it is open source you will be able to check it rather than take our word for it.
What it deliberately cannot do
Some blockers filter explicit images inside apps and on ordinary websites. Bastion does not, and will not. Doing it means decrypting your traffic with a certificate installed on your phone — at which point the app can read your messages, your email and your banking, and you are trusting it not to. That is the surveillance we are refusing.
Bastion reads only the name of the server your phone is about to talk to. That is enough to block a site, force safe search, and stop apps from sneaking around the filter. It is not enough to see inside Instagram or X — for those, you can block the platform outright in one tap instead.
Android now, desktop next
An iPhone version is possible but would be a weaker thing. Apple does let an app filter DNS for the whole system, so the blocklist and safe search would work — but it does not let an app inspect the connections of other apps, and there is no way to stop someone simply deleting it. Bastion exists to hold in a weak moment, and on iPhone it would not hold. A desktop version has neither problem and is the more likely next step.
What it won’t catch
Bastion is a barrier, not a wall — one layer on top of your own decisions, not the whole solution. A keyword filter has limits, and it is only fair to know them:
- Misspellings and alternative spellings the filter does not know.
- Images and video with no text to read.
- Private browsing, and browsers the filter does not cover.
- Anything outside the browser — messages, other apps and social media.
Open source
The promise that nothing leaves your phone is only worth something if you can check it. That is why Bastion will be open source once the code is ready — so anyone can read along and see exactly what the app does.