> ## Documentation Index
> Fetch the complete documentation index at: https://docs.boomfi.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# External Account Overview

> Register the crypto wallets and bank accounts your payouts are allowed to reach.

An **external account** is a payout destination you control, outside BoomFi's custody: a crypto wallet address, or a bank account. Registering one whitelists it: payouts can only send funds to an external account created here.

## Why whitelist first

Registering an external account is the sensitive step, not paying out to it afterward:

* When you authenticate with a Bearer session, registering requires **step-up verification** (`X-Step-Up-Token`).
* Once an account is registered and enabled, payouts to it need no per-request OTP — the whitelisting step already proved you control the destination.
* Disabling or deleting an external account immediately stops any future payout (including scheduled automations) from reaching it. Payouts already in flight are unaffected.

## Register a destination

Both kinds are registered through the same endpoint, `POST /accounts/external-account`, distinguished by `type`:

* [Whitelist a crypto account](/whitelist-external-account/whitelist-crypto-account) — a wallet address on a specific chain.
* [Whitelist a fiat bank account](/whitelist-external-account/whitelist-fiat-bank-account) — a bank beneficiary for fiat settlement.

## Addressing a destination

Every external account has a `reference` — your own identifier for it — alongside its numeric `id`. A payout can name the destination by either: `destination_account_id` or `destination_account_reference`.

An org can register at most one destination per (`reference`, chain) pair: registering the same reference again on the same chain returns **409**.

## Prerequisites

* [Authentication](/authentication) (`X-API-KEY`, or a Bearer session with step-up)
* A supported currency and, for a crypto account, a supported chain (see [Networks and Currencies](/pricing/networks-and-currencies))

## Next steps

* [Whitelist a Crypto Account](/whitelist-external-account/whitelist-crypto-account)
* [Whitelist a Fiat Bank Account](/whitelist-external-account/whitelist-fiat-bank-account)
* Once registered and enabled, use the account as a payout destination.