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The Telnyx Verify API delivers one-time passwords (OTPs) and validates them across SMS, voice call, WhatsApp, and flash call channels. Built on Telnyx’s carrier-grade messaging and voice network, Verify handles code generation, delivery, expiration, and validation so you can add two-factor authentication without building the infrastructure yourself.

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How it works

  1. Create a verification — Send a POST request specifying the phone number and channel (SMS, voice, WhatsApp, or flash call). Telnyx generates a code and delivers it.
  2. User receives the code — The end user receives the OTP on their device.
  3. Submit the code — Your application sends the code back to the Verify API. Telnyx responds with whether the code is valid, expired, or incorrect.

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Key features

  • Multiple channels — Deliver OTPs via SMS, voice call, WhatsApp, or flash call from a single API.
  • Verify profiles — Configure sender settings, code length, expiration, and delivery preferences per use case.
  • Custom templates — Customize the message text and branding for SMS and WhatsApp verifications.
  • Rate limiting and fraud prevention — Built-in protections against enumeration attacks, toll fraud, and excessive retry attempts.
  • Webhooks — Receive real-time status updates on verification delivery and completion.

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Common use cases

  • Login 2FA — Add a second factor to user sign-in flows.
  • Transaction verification — Confirm high-value actions like payments or account changes.
  • Account recovery — Verify identity before resetting passwords or recovering accounts.
  • Phone number confirmation — Validate that a user owns the number they provided during registration.

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Get started

Quickstart

Send and verify your first OTP in a few lines of code.

Custom Templates

Customize the message your users receive.

Rate Limiting

Configure fraud prevention and rate limits.

Webhooks

Track verification status in real time.