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

# Bridging

> In this guide, we will learn how to successfully bridge funds from an origin to a vault.

## Identifying the vault and origin

The first step is to identify the vault you want to bridge to. This is based on
the currency and chain on which you want to receive the funds. You can chose to
*hardcode* trusted vault addresses (like the ones deployed by the Relay team),
or use our [Backend API](../backend) to query the vaults available on a specific
chain and currency.

Once you have identified the vault, you need to identify the origin on which you
want to perform your deposit. There again, you can use our Backend API to query
the origins available for a specific vault. You can filter these origins by
their chain and currency. Please note that a vault may have "different"
currencies than the ones you deposit. This is for example the case for deposits
of native tokens (Ethereum) who are in fact going to a wrapped token (WETH)
vault.

Once you have identified the origin, you should check a few things:

* that the vault has enough liquidity to handle your deposit (you can query the
  vault's balance on the Backend API) comparing its `outstandingDebt` and
  `totalAssets` values.

* that the origin's specific `outstandingDebt` is sufficient to handle your
  deposit. This is the maximum amount of funds that can be bridged from that
  origin at any given time. You can query this value on the Backend API. You can
  use the vault's `authorizedOrigins` field to check the origins available for a
  specific vault (it also returns the `bridgeFee` and `cooldown` that are
  useful).

## Performing the deposit

Finally, it is time to perform the deposit. In order to perform a deposit, you
need to first query the `getFee` method on the bridge contract in order to get
the fee that will be charged for the deposit itself. These are the fees
collected by Hyperlane to send the message to the vault. You will need to
specify the `amount`, `recipient` and `poolGas` parameters (a default of 300,000
gas should be sufficient for most cases). Once you have the fee, you will need
to call the `bridge` method on the origin contract, passing the `amount`,
`recipient`, `poolGas` and an extra `data` parameters. You MUST also pass a
`value` matching the result of the `getFee` call from above. The `data`
parameter is optional and can be used to pass extra information to the
underlying bridge proxy (see [BridgeProxy](../contracts/RelayBridge)) and could
be `0x0` in most cases.

The `recipient` address will receive the funds on the vault chain as soon as the
message has been processed by Hyperlane (and the cool down period has been
respected). The `recipient` address can be the same as the one you used to
deposit, or a different one. This is useful if you want to bridge funds to a
different address than the one you used to deposit.

## Using the Hyperlane explorer

Messages are passed between the origin and the vault using Hyperlane. You can
use the [Hyperlane Explorer](https://explorer.hyperlane.xyz/) to track the
messages sent from the origin to the vault. This can be useful to check if your
message has been sent and is being processed by the vault. For this, check the
`messageId` parameter of the `DispatchId` event emitted by `Mailbox` contract on
the origin chain. Here
[is an example](https://explorer.hyperlane.xyz/message/0x9122e85feb8638817b51605152992058bf3a0f683ae495240bbe8f78e7c7da2f)
for this transaction
[on the Zora chain](https://explorer.zora.energy/tx/0x64229c089b71bae499646abdd22df4562514eea5c264fdb07c80bdb331ab7670?tab=logs).