# after_crosschain_balance_change · FT4 Rell API · Chromia Docs (concept)

> @extendable function after_ crosschain_ balance_ change(sender: account , recipient: account , asset: asset , amount: big_ integer, has_ changed_ sender: b

Source: https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.core.crosschain/after_crosschain_balance_change/

FUNCTION

# after\_crosschain\_balance\_change

```signature
@extendable function after_crosschain_balance_change(sender: account, recipient: account, asset: asset, amount: big_integer, has_changed_sender: boolean, has_changed_recipient: boolean)
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/crosschain/extensions.rell#lines-165)

Extendable function that allows the developer to add more functionality to the
`update_balances_if_needed` function, after the balance change is applied.

This allows, for example, to check that any condition is met after the balance change is
applied. Or to modify the balance or amount after it is changed.

If this function throws, the balance change will not be applied.

Throws when any extension of this function throws.

**Parameters**

* **sender** — the account that has transferred the tokens
* **recipient** — the account that will receive the tokens
* **asset** — the asset that was transferred
* **amount** — the amount that was transferred
* **has\_changed\_sender** — whether the sender's balance has changed
* **has\_changed\_recipient** — whether the recipient's balance has changed

[View this page on docs.chromia.com](https://docs.chromia.com/pages/ft4-rell/-f-t4%20-library/lib.ft4.core.crosschain/after_crosschain_balance_change.html)Generated API reference, mirrored from the live docs