# OTP SMS Provider: One-Time Passcode Delivery | ZafeConnect

> Deliver one-time passcodes by SMS or voice with failover routing and fast delivery. Best practices for OTP and two-factor authentication.

Canonical URL: https://www.zafeconnect.com/use-cases/otp-verification
Language: en
Last modified: 2026-11-09

## One-time passcode (OTP) verification

URL: https://www.zafeconnect.com/use-cases/otp-verification

Get verification codes to users in seconds, with fallback channels when a network struggles.

In brief: Fast, reliable delivery of verification codes. ZafeConnect provides A2P SMS, Voice API and Numbers Lookup for this, connects to 190+ countries through direct operator connections, complemented by partner direct routes, and charges only for delivered messages.

One-time passcodes confirm that a user controls a phone number: at sign-up, at login, and before sensitive actions. They only work if they arrive within seconds.

ZafeConnect delivers codes through A2P SMS and can add voice as a fallback, with failover routing and analytics so you can see delivery performance.

What matters:
- **Speed:** A code that arrives late is a lost user.
- **High deliverability:** Failed codes mean support tickets and abandoned sign-ups.
- **Abuse protection:** Verification endpoints attract fraud such as artificially inflated traffic, so use rate limits and monitoring.
- **The right assurance level:** SMS suits many cases, but high-risk actions may need stronger methods.

How ZafeConnect helps:
- **Failover routing:** Messages route around network issues through alternative routes or regions.
- **Voice fallback:** Deliver the code by a spoken call if text fails.
- **Number lookup:** Validate numbers up front to cut failed sends.
- **Analytics:** See delivery performance so you can react quickly.

Typical flow:
1. Request: A user asks for a code in your app or website.
2. Send: Your system sends the code through the ZafeConnect API.
3. Verify: The user enters the code and your system confirms it.

Recommended products: A2P SMS (https://www.zafeconnect.com/products/sms), Voice API (https://www.zafeconnect.com/products/voice-api), Numbers Lookup (https://www.zafeconnect.com/products/numbers-lookup), SenderID (https://www.zafeconnect.com/products/sender-id), Analytics (https://www.zafeconnect.com/products/analytics)

FAQ:
Q: How fast are codes delivered?
A: Delivery speed depends on the destination network. ZafeConnect uses failover routing and reports a delivery rate of over 98%. Talk to us about your target countries.

Q: What is SMS pumping?
A: Also called artificially inflated traffic: attackers trigger large numbers of verification messages to numbers they profit from. Rate limiting, number validation and monitoring reduce the risk.

Q: Should we use SMS or an authenticator app?
A: SMS is convenient and familiar, while app- or hardware-based methods are generally considered stronger. Many companies offer both and choose based on risk.