---
title: "What is Out-of-band verification? Definition"
description: "Out-of-band verification is confirming a request through a separate channel and contact details the requester did not provide - for example, calling a..."
url: https://realpayee.com/glossary/out-of-band-verification
canonical: https://realpayee.com/glossary/out-of-band-verification
date_published: 2026-10-05
date_modified: 2026-10-05
author: RealPayee
---

# Out-of-band verification

> Out-of-band verification is confirming a request through a separate channel and contact details the requester did not provide - for example, calling a vendor's known number after an email request. It defeats attackers who control the original channel, such as a compromised mailbox.

_Published 2026-10-05 · Updated 2026-10-05 · By RealPayee_

## Related terms

- [Callback verification](https://realpayee.com/glossary/callback-verification): Callback verification is confirming a payment instruction or bank-detail change by phoning the requester on a number you already had on file - never one supplied in the request.
- [Liveness check](https://realpayee.com/glossary/liveness-check): A liveness check confirms that a real, physically present person is in front of the camera - not a photo, recording, mask or deepfake - usually during a live selfie.
- [Vendor verification](https://realpayee.com/glossary/vendor-verification): Vendor verification is confirming that a supplier is legitimate and that the bank account you pay belongs to it - at onboarding and whenever its payment details change.

## Why it matters for finance teams

Most payment fraud reaches AP as a request that looks legitimate. Understanding out-of-band verification helps your team spot it and apply the right control: verify bank-detail changes and large payment requests with the real person, out-of-band, before money moves. Our free [bank-change policy template](https://realpayee.com/templates/vendor-bank-change-policy) puts that into a written rule.

Full glossary: https://realpayee.com/glossary · All terms as JSON Lines: https://realpayee.com/feeds/glossary.jsonl

## Related

- [Vendor verification: how to verify vendor bank details before you pay](https://realpayee.com/vendor-verification) - A practical guide to vendor verification for finance teams: how to confirm vendor bank-detail changes, run callbacks, and prevent vendor impersonation fraud. (markdown: https://realpayee.com/vendor-verification.md)
- [Wire fraud prevention: how to stop bank wire fraud](https://realpayee.com/wire-fraud-prevention) - Controls that prevent business wire fraud: out-of-band verification, payment thresholds, dual approval and audit trails. (markdown: https://realpayee.com/wire-fraud-prevention.md)
- [What is out-of-band verification?](https://realpayee.com/answers/what-is-out-of-band-verification) - What out-of-band verification means for payments and vendor changes, examples, why it beats replying to an email, and its limits. (markdown: https://realpayee.com/answers/what-is-out-of-band-verification.md)

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