Mobile app & SMS verification

Live payments made with SMS-verified methods (bKash, Nagad, etc.) are confirmed automatically by forwarding the provider's confirmation SMS from a paired Android phone to Fastaar. The Fastaar mobile app runs a background service on that phone to do this.

Installing the app (before it's on Play Store)

The Fastaar app isn't published on Google Play yet, so you'll install it directly as an APK file instead of through the Play Store. Android adds a few extra steps for this — they're one-time setup, not something you'll need to repeat later.

1. Turn off Play Protect scanning. Open the Play Store app → tap your profile icon (top right) → Play Protect → the gear icon → turn off "Scan apps with Play Protect." Without this, Android may block or repeatedly flag the install since the app isn't from the Play Store yet.
2. Download and install the app. Download the APK file to your phone. When you open it, Android will prompt to allow installs from that source (browser or file manager) — tap Settings on the prompt, then enable "Allow from this source." Go back and tap install.
3. Remove app restrictions. Go to phone Settings → Apps → Fastaar, open it, tap the ⋮ menu (top right), and choose "Unrestricted" (wording varies by phone brand — look for anything about app restrictions or battery usage limits and set it to unrestricted).
4. Open the app and grant every permission it asks for (SMS and notifications) — these are required for automatic payment verification to work at all; see how sender syncing works below for what the SMS permission is actually used for.
5. Disable battery optimization for the app. Settings → Apps → Fastaar → Battery → set to "Unrestricted" or "Don't optimize." The app will also show a warning on its Home screen with a direct shortcut to this if you skip it here.

Steps 3 and 5 matter most on Xiaomi, Oppo, Vivo, and OnePlus phones — these brands aggressively kill background apps by default, which stops SMS forwarding even after pairing succeeds.

Pairing a phone

• In the merchant panel onboarding flow (or Settings → Devices), generate a pairing QR code.
• Open the Fastaar app on the Android phone that receives your MFS account's SMS and scan the code.
• Once paired, the app runs a foreground service that watches for SMS and forwards matching messages.

How sender syncing works

The app doesn't decide which SMS senders to watch on its own — it fetches that list from Fastaar. Every 2 minutes, the app sends a heartbeat to the server, and the server responds with the current set of SMS sender IDs to watch, computed live from your active payment methods and their SMS-check templates. The app saves that list locally and uses it to decide which incoming SMS to forward.

This means adding or removing a payment method takes effect automatically — you don't need to re-pair the device. The change is picked up on the phone's next heartbeat, so allow up to 2 minutes (or tap Sync now on the Home screen to force it immediately).

Troubleshooting: senders not updating

If a newly added payment method's SMS still isn't being forwarded after a few minutes, check:

• Forwarding is turned on — the heartbeat loop only runs while "Start forwarding" is enabled on the Home screen.
• The app is actually running — if the "Battery optimization may pause forwarding" warning is showing, tap it to exempt Fastaar; some OEMs (Xiaomi, Oppo, Vivo) aggressively kill background services otherwise.
• Tap "Sync now" to force an immediate heartbeat instead of waiting up to 2 minutes.
• The payment method is active and its provider template has SMS sender IDs configured — check the payment method's status in the merchant panel.