Every product team eventually needs phone verification — for signup, login, payments, or fraud prevention. The question isn't whether to verify phone numbers, but whether to build SMS delivery yourself or use an OTP API.

The hidden cost of DIY SMS

  • Carrier agreements and routing across 190+ countries
  • Code generation, expiry, retry logic, and brute-force protection
  • Compliance: log retention, PII masking, and audit trails
  • Monitoring delivery rates and handling operator-specific failures

What an OTP API gives you

CapabilityDIY SMSOTP API
Time to productionWeeks–monthsHours
Fraud protectionBuild yourselfBuilt-in rate limits & blocklists
Pricing modelPer SMS sentPer successful verification
Global coveragePer-country setup190+ countries out of the box

When to use an OTP API

If verification is a feature — not your core product — an OTP-as-a-Service platform lets you ship faster, pay only for successes, and inherit fraud controls that would take a dedicated team to maintain.

DoneOTP offers a drop-in widget and two-endpoint REST API. No platform fee — integrate in an afternoon and scale to millions of verifications.