One-Time Password SMS Verification

Sending one-time passwords via SMS is a great way to keep your customers' credentials safe. Unlike static passwords, OTPs expire after one use or a short time window - typically 30 to 60 seconds - providing the least amount of surface area for potential attackers to steal client credentials with. It's a convenient system for both parties since it doesn't require a designated app and it can all be done through a single API integration.

OTP Compared to Other Methods

Method	Pros	Cons
SMS OTP (CloudOTP)	No app install, universal device support, familiar UX	Requires phone number
Authenticator Apps	No network dependency, works offline	Requires app install, user friction
Email OTP	Works without phone number	Slower delivery, often missed in spam
Hardware Tokens	Highest security	Expensive, easy to lose

Implementation via the API

For more on how to use the CCAI API, check out the corresponding part of the documentation here.

# Request an OTP code be sent to a phone number
curl -X POST https://api.cloudcontactai.com/otp/send \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "+14155551234",
    "expiration_seconds": 60
  }'

{
  "status": "sent",
  "otp_id": "otp_8f3k2j1",
  "expires_at": "2026-07-21T14:31:40Z"
}

# Validate the code entered by the user
curl -X POST https://api.cloudcontactai.com/otp/verify \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "otp_id": "otp_8f3k2j1",
    "code": "847291"
  }'