> ## 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.

# Resend and invalidate challenges

> Resend delivery or invalidate an outstanding challenge.

<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>

* Resend: `POST .../otp/challenges/{challengeId}/resend` (`otp.challenge.create`)
* Invalidate: `POST .../otp/challenges/{challengeId}/invalidate` (`otp.challenge.verify`)
* Read status: `GET .../otp/challenges/{challengeId}` (`otp.challenge.read`)

Expiry and lockout are reflected in challenge status. Webhook events are emitted
for `verified`, `expired`, and `locked` only — not for SMS delivery of the code.


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