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

> @extendable function before_ register_ account(account_ id: byte_ array) Extendable function that allows the developer to add more functionality to the reg

Source: https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.core.accounts.strategies/before_register_account/

FUNCTION

# before\_register\_account

```signature
@extendable function before_register_account(account_id: byte_array)
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/accounts/strategies/module.rell#lines-28)

Extendable function that allows the developer to add more functionality to the
`register_account` function, before the registration happens.

This allows, for example, to add fees on registration or check that any given condition
is present before the registration can be completed.

If this function throws an exception, the registration will not happen.

When using the transfer submodule, the strategies defined there already implement extensions
of this function, requiring no additional code from the developer. This function should
only be extended if functionality that is not found in the predefined strategies is required.

In some cases, creating a new strategy is a better alternative: this function will run on
all account registrations, regardless of the strategy they used.

Throws if any extension of this function throws.

**Parameters**

* **account\_id** — the ID of the account that will be registered

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