SmsApp: Virtual Number Platform for OTP Verification

SmsApp rents virtual phone numbers that receive one-time verification codes from messaging apps, email and 150+ other services. Customers can also keep a number for a month. They pay from a prepaid wallet, and resellers automate purchases through a REST API.

I've been the lead developer since February 2026. My first major change was moving the backend from Firestore to MySQL, and I've written about 99% of the code changes since then.

Prepaid wallet that can never go below zero, with each refund paid exactly once.

Automatic refunds when no code arrives, which still work correctly after a crash.

Payments by card and through two crypto providers, with authenticated webhooks.

Fraud controls: 3-D Secure checks, card holds, bans tied to shared IPs, and chargeback tracking.

Supplier routing by delivery rate, price and stock, with failing suppliers switched off automatically.

Rentals: monthly rentals, shared numbers, and a receive-only email inbox for each rental.

SEO pages pre-rendered in 24 languages, including right-to-left Arabic and Hebrew.

Payment callbacks you can't trust: one provider's callbacks aren't signed, so I treat them only as hints. Each one is confirmed against that provider's API before any money is credited.

Refunds that never pay twice: the refund job uses a lock that releases itself if a run hangs, and each refund is claimed atomically so it can't be paid twice.

24 interface languages.

Numbers available in 150+ countries.

4,700+ pages across 24 language sitemaps.

4,000+ automated tests across server, web and mobile.

Live: https://smsapp.io