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Overview

OTPless Telecom Intelligence APIs let you query carrier-level signals for a phone number directly from your backend. Use these signals as a pre-authentication risk layer alongside your primary auth flow. Available APIs:
  • SIM Swap Check — Detect whether a phone number’s SIM was recently swapped. A recent swap can indicate a SIM-swap attack targeting your users.
  • Call Forwarding Check — Check whether call forwarding is active on a number. Active forwarding can divert calls (including voice OTPs) to an attacker.

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Authentication

All requests require your OTPless credentials as request headers: These are the same credentials you use for other OTPless APIs. Do not expose them in client-side code.

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Base URL

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API reference

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HTTP status codes

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Error model

  • HTTP 4xx: Request rejected. Body is an error object only (message, errorCode, description).
  • HTTP 200 with success: false: Request accepted, but the check could not be completed. Inspect the error object in the body.
See the error reference for the full list of error codes.

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Endpoints

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Support

For access, credentials, or questions about these APIs, contact OTPless support or refer to your onboarding documentation.