Your messages never leave your phone
To spot a scam, WallUPI has to look at genuinely private things: who you pay, what you were sent, whether you are on a call. So the looking happens on your device. That is an arrangement, not a promise.
It stays on the device
text
result
Checked where you read it
A compact detector runs on the phone itself. It reads each message where it already sits and produces the reading there, with no server involved.
- Messages read in
- Your phone
- Copy of your inbox
- None, anywhere
- Works offline
- Yes, the checks that matter run locally
- Ever leaves
- Only the stripped wording of a genuinely unclear message
The one exception, stated exactly
When a message is genuinely ambiguous, a cleaned copy of its wording can be checked more carefully. Before it goes anywhere, the identifying parts come out. What is left is the shape of the sentence, not a record of you, and it is not stored against your identity because your identity was never attached.
Dear Kavy, your account XX1234 is BLOCKED. Call +91 99XXXXXXXX and pay Rs.99 at fake-bank.xyz
Dear name, your account number is BLOCKED. Call phone and pay amount at link
Plainly: what stays and what does not
No fine print. Anything not listed here is simply never collected.
Stays on your phone
- The text of every message you receive
- Your contacts, and who you have paid before
- Your payment history and the amounts in it
- The fact that a call was in progress
- Every risk reading it has ever produced for you
Never sent, in any form
- Your name, your number or your UPI ID
- Your contact list
- Your balance, your bank or your account number
- Who you pay, how often, or how much
- Anything at all, sold or handed to an advertiser
Why each permission is asked for
An app that wants to read your messages should justify it in one sentence. Here are those sentences, and what you lose if you say no.
| Permission | Why it is needed | If you refuse it |
|---|---|---|
| Messages | To spot the scam text before it turns into a payment. Read on the phone, never uploaded. | The earliest warnings stop. Payment checks carry on. |
| Call state | Only to know whether a call is happening while you pay. It does not record, listen to or transcribe anything, and does not care who is calling. | The strongest scam signal is lost. Everything else still runs. |
| Contacts | To tell a stranger from someone you know, which is most of the difference between a normal payment and a dangerous one. | Telling strangers from people you know gets harder. Everything else still runs. |
| Nothing else | No location, no microphone, no camera beyond scanning a code, no photo library, no browsing history. | Nothing to refuse. |
Check it yourself
Install the demo, then switch the network off entirely. The message checking keeps working, which is the clearest proof of where it happens.