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

> A set of requirements to be satisfied to register an account. struct rule {
 timeout_ days: integer = 0;
 strategies: list<text>;
 blockchains: allowlist ;

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

STRUCT

# rule

A set of requirements to be satisfied to register an account.

```signature
struct rule {
 timeout_days: integer = 0;
 strategies: list<text>;
 blockchains: allowlist;
 senders: allowlist;
 recipients: allowlist;
 require_same_address: boolean = 0;
 allow_all_assets: boolean = 0;
 asset_limits: list<asset_limit>;
}
```

`timeout_days: integer = 0;`
:   How many days must pass after the transfer being received by the non-existing account
    before the account can no longer be registered and the transfer can be recalled.

`strategies: list<text>;`
:   What strategies can be used to register an account if all requirements of this rule
    are met.

`blockchains: allowlist;`
:   From which blockchains must assets arrive to create an account. For on-chain transfers,
    this blockchain's ID will appear in the `allowlist`

`senders: allowlist;`
:   Which accounts can send to a non-existing account to register it

`recipients: allowlist;`
:   Which accounts can be registered

`require_same_address: boolean = 0;`
:   Whether a certain sender can only register an account with its same ID.
    Only makes sense for cross-chain transfers.

`allow_all_assets: boolean = 0;`
:   Whether all assets can be sent.
    If true, `asset_limits` won't be parsed - minimum amounts cannot be set.

`asset_limits: list<asset_limit>;`
:   What minimum amounts of each assets must be sent to register an account.

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/core/accounts/strategies/config_utils.rell#lines-70)

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