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

> @mount("ft4.crosschain.apply_ transfer")
operation apply_ transfer(init_ transfer_ tx: gtx_ transaction, init_ tx_ op_ index: integer, previous_ hop_ tx: g

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

OPERATION

# apply\_transfer

```signature
@mount("ft4.crosschain.apply_transfer")
operation apply_transfer(init_transfer_tx: gtx_transaction, init_tx_op_index: integer, previous_hop_tx: gtx_transaction, op_index: integer, hop_index: integer)
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/external/crosschain/operations.rell#lines-244)

This operation must be called on every chain listed in the `hops` array
provided to the `init_transfer` function which corresponds to this transfer.

When this is done, one of two things will happen:

* If this is an intermediary hop, this chain will update its internal record of
  which chain that owns how much of what asset
* If this is the final hop, the transferred amount will be credited to the recipient account

In the case where this is the last hop and the recipient account does not exist,
one of two things can happen:

* If the create on transfer account creation strategy is enabled, the assets will be received and
  the recipient will be able create the account and claim them.
* If the feature is not enabled, the transfer will be rejected, in which case, the sender can
  get their assets back by calling the `cancel_transfer` in the reverse hops order.

Anyone can call this operation on behalf of any transfer, but it needs to include an `iccf_proof`
operation which prove that the transaction was applied in the previous hop.

The functionality provided by `apply_transfer` can be modified by extending
`before_apply_transfer` and `after_apply_transfer`

Throws `"`TRANSFER EXPIRED"` if deadline is a past timestamp

Throws `"MISSING ACCOUNT"` if all these conditions apply:

* this chain is the last chain in the crosschain transaction
* the account corresponding to `recipient_id` does not exist
* creating account on crosschain transfer is not enabled on this chain

Throws if additional conditions provided through extensions of `before_apply_transfer` and
`after_apply_transfer` are not satisfied

Throws if the current transfer is misconfigured. Common cases are:

* the next hop or the previous one are:
  + equal to one another
  + this blockchain's RID
  + the ID of an account on this chain which is not a blockchain account
* amount is:
  + not in the accepted range (0, 2^256) (exclusive)
  + higher than the blockchain account balance they're coming from
* the asset is not registered on this chain
* input is malformed:
  + arguments found in `init_transfer_tx` and `previous_hop_tx` do not match
  + `hop_index` is out of bounds
  + `previous_hop_tx` has not been sent to the chain that comes before this one on the transfer
    hops
* the transfer has already been applied, canceled or unapplied on this chain.
* the chain at `hop_index` on the init transaction is not this chain
* the `op_index` on `previous_hop_tx` does not point to:
  + `init_transfer` when `hop_index` is 0
  + `apply_transfer` otherwise
* the `init_tx_op_index` does not point to `init_transfer` on its `init_transfer_tx`
* the operation preceding `init_transfer` is not an auth operation

Throws if all these conditions apply:

* this chain is the last chain in the crosschain transaction
* the account corresponding to `recipient_id` does not exist
* creating account on crosschain transfer is enabled on this chain
* the function implementing the account creation strategy being used (extension of
  `create_on_crosschain_transfer`) has conditions which are not satisfied

Throws if the transaction is missing the `iccf_proof` operation, which demonstrates that
the block containing the `previous_hop_tx` has been anchored from the previous chain.

Requires no flags - no authorization is performed to apply a transfer.

**Parameters**

* **init\_transfer\_tx** — the `gtx_transaction` that represents the tx containing the `init_transfer` operation on the initial chain
* **init\_tx\_op\_index** — the index of the `init_transfer` operation in `init_transfer_tx`
* **previous\_hop\_tx** — the tx containing the `init_transfer` or `apply_transfer` operation from the previous step. In the first hop, `init_transfer_tx` and this argument will be the same
* **op\_index** — the index of the `apply_transfer` operation in `previous_hop_tx`
* **hop\_index** — which index in the hops array provided in the original transaction this chain represents.

**See Also**

* `core.auth.is_auth_op` — for information on auth operations
* `core.crosschain.before_apply_transfer` — to add custom logic before this operation
* `core.crosschain.after_apply_transfer` — to add custom logic after this operation
* `core.crosschain.applied_transfers` — to know more about the crosschain transfer workflow
* `core.crosschain.is_create_on_crosschain_transfer_enabled` — to know more about account creation on crosschain transfer

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