> ## Documentation Index
> Fetch the complete documentation index at: https://developers.1-funnel.org/llms.txt
> Use this file to discover all available pages before exploring further.

# OTP overview

> Managed OTP challenges without exposing codes or hashes.

<Warning>
  **Developer Preview**

  This documentation describes the upcoming 1Funnel External Integration API.

  The documented API endpoints and authentication services are not yet available
  for public integration.

  You can explore the API specifications, request and response schemas, webhook
  events, and integration guides.

  Sandbox and production availability will be announced separately.
</Warning>

OTP operations manage challenge lifecycle: create, verify, resend, invalidate,
and read status. Public responses never include OTP codes, hashes, or
verification secrets. Challenge status is distinct from SMS delivery status.


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