Preventing SMS Pumping & Toll Fraud in Nepalese Web and Mobile Applications
SMS Pumping (also known as Artificially Inflated Traffic or AIT) occurs when automated botnets exploit public OTP verification forms to trigger thousands of SMS messages to premium numbers or sequential blocks. If left unchecked, SMS pumping can drain thousands of dollars in credit balances overnight.
1. Restrict Destination Country Codes
If your app serves users specifically in Nepal, strictly enforce +977 prefix validation on your backend API. Reject requests to international destination ranges before calling your SMS gateway provider.
2. Implement Invisible Bot Detection (reCAPTCHA / Cloudflare Turnstile)
Attach Cloudflare Turnstile or Google reCAPTCHA v3 tokens to your "Send OTP" button. Require valid risk score tokens prior to dispatching messages to target phone numbers.
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