The Android Accessibility Service API has a reputation problem. It's the same API used by keyloggers, stalkerware, and malicious apps to silently harvest passwords and monitor private conversations. Google has repeatedly tightened restrictions around it, and for good reason.
BlockerPlus uses this API as the foundation of its blocking mechanism. We want to be completely transparent about how we use it, what we access, and what we deliberately choose not to access.
What the Accessibility Service API actually does
The Accessibility Service was originally designed to help users with disabilities interact with Android apps. It allows a service to observe UI events happening on screen — what windows are open, what text is visible, what the user is interacting with — and to take actions on the user's behalf.
The same capabilities that make it powerful for accessibility make it attractive for malicious developers. An app with Accessibility Service permissions could, in theory, read everything you type, capture every screen you see, and interact with any app on your device.
"Power without transparency is the definition of dark patterns. We chose the opposite."
What BlockerPlus accesses — and what it doesn't
When BlockerPlus's Accessibility Service is running, it observes:
- The current foreground app's package name — which app is open
- URL bar content in supported browsers — to check against our blocklist
- On-screen text in specific content areas — for keyword-based blocking
- Window state change events — when apps open and close
We deliberately do not access:
- Password fields or secure text inputs
- Messaging app content (WhatsApp, Telegram, SMS)
- Banking or financial app screens
- Any data not directly relevant to a blocking decision
- Any data stored or transmitted off the device
All blocking decisions happen locally on your device. We do not send URLs, screen content, or any other observed data to our servers. The blocking engine is entirely on-device.
Google Play compliance
Google Play has strict policies around the Accessibility Service API. BlockerPlus complies with all of these requirements. Our Play Store listing explicitly describes our use of the service. Our in-app permission request screen explains exactly what we access and why. We have passed Google's review process and maintain compliance with each policy update.
Why we think this is worth defending
There are legitimate calls to restrict the Accessibility Service API more aggressively, given its history of abuse. We take those concerns seriously. But responsible use of this API enables genuinely useful applications that cannot be built any other way. For the 200,000+ people who have used BlockerPlus to change a behaviour they genuinely wanted to change, that capability has been life-changing.
The answer to API abuse is not to eliminate powerful APIs. It's to build transparency, disclosure, and genuine user control into every app that uses them.