Demo Features FAQ About

Pay over UPI.
No internet.

AHD uses *99# (India's USSD-based UPI protocol) to send money, check balance, and scan QR codes entirely over your SIM's voice channel. Works on Airtel, Vi and BSNL with zero data.

Download APK
Demo

See it working.

A real payment on a real phone. Airplane mode on. No tricks.

Scanning a merchant QR code with AHD
Features

What it does.

Built around one constraint: no internet permission in the manifest. The app is physically incapable of making a network call.

Auto *99# dialing

Accessibility Service drives the carrier USSD dialog in the background. You stay in the app the whole time.

QR scanner

Camera reads merchant UPI QR codes. Parsed locally, with no network call to decode anything.

Balance check

Check your bank balance over *99# the same way. No data needed.

Local history

Up to 200 transactions stored on-device with SQLCipher encryption. Swipe to delete, tap to retry.

Manual fallback

Skip Accessibility altogether: manual mode opens your dialer pre-filled with the *99# sequence.

Open source · MIT

Every permission, every API call is on GitHub. Verify it yourself before installing.

How it works

The flow, step by step.

Scan, fail over from data, and pay through *99# without ever leaving AHD.

AHD payment flow: scan QR, payment fails without internet, AHD detects no internet, pays over *99# instead, and confirms success
FAQ

Common questions.

What is *99# UPI?
*99# is India's USSD-based UPI service built by NPCI. It works without internet. You dial a code, your bank shows menus through SMS-style dialogs over the voice channel, and you reply to send money. Works on any phone with a basic cellular signal.
Which carriers work?
Airtel, Vodafone (Vi), and BSNL: yes. Jio: no. That's a Jio network-level constraint, not an AHD limitation.
AIRTEL ✓ VI ✓ BSNL ✓ JIO ✗
What are the two modes?
Auto

AHD handles the carrier dialog automatically using Accessibility Service, keeping you in AHD throughout the payment.

Manual

Copies the UPI ID and opens your dialer pre-filled with the *99# code. You navigate the menus yourself. No Accessibility Service needed.

Why does it need Accessibility Service?
Android's only public USSD API can't navigate multi-step menus. The Accessibility Service is what lets AHD automatically type your amount, UPI ID, and PIN into the carrier's dialog so you don't have to. Without it, use Manual mode.
Android 13+ says "Restricted settings" (can't enable Accessibility)
Since AHD is sideloaded (not from Play Store), Android 13+ blocks restricted settings like Accessibility by default. Fix:
1
Settings → Apps → AHD
2
Tap the ⋮ three-dot menu (top right)
3
Allow restricted settings → confirm with your PIN or fingerprint
4
Return to AHD → enable Accessibility. It works now.
How do I enable banking on *99# first?
This one-time setup links your bank account to the *99# channel. After this, AHD handles everything.
1
Open your phone's dialer and call *99#
2
Enter your bank name when prompted (SBI, HDFC, ICICI, etc.)
3
Follow on-screen prompts to link your bank account
Done once, you never need to do it again.
What if a payment fails?
AHD shows the carrier's exact error message. Common causes: wrong PIN, bank not linked to *99#, daily limit exceeded, wrong UPI ID, or weak signal. Tap the failed transaction in history to see the full reply and retry in one tap. A 25-second timeout prevents stuck sessions.
What are the transaction limits?
₹5,000 per transaction and ₹10,000 per day. These are NPCI network-level limits for *99#, not set by AHD.
Is AHD on the Play Store?
Not currently. Download the APK from GitHub releases.

More → full FAQ

Get it

Download AHD.

Android APK, sideload, no Play Store. Or the PWA, which works on any phone with no install needed.

Download APK · Android 8+

Source on GitHub · MIT License