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Reverse OTP with iMessage verifies a user’s phone number by having the user initiate a message to you over iMessage, rather than you reaching out first. Compared to traditional SMS OTPs, this workflow offers several advantages:
  • Sending an iMessage requires the user to use their own Apple device, making it much more difficult for attackers to fake and giving you greater confidence in the user’s authenticity.
  • You save on operational costs because you’re not paying to have potentially dozens of lines to send outbound OTPs to users.
  • iMessage generally has high delivery and reliability rates, especially compared to international SMS, where texts may be blocked or filtered.
  • Ratelimits don’t apply to inbound iMessage, so you can verify millions of users using just one iMessage-capable line.
Reverse OTP with iMessage requires a leased iMessage-capable line, and an iMessage entitlement.

Implement Reverse OTP with iMessage

Read the API documentation for initiating, verifying, and cancelling a Reverse OTP with iMessage session.