Relayer Setup

The relayer is the off-chain component that makes cross-chain messaging work. It monitors source chains for outgoing warp messages, aggregates BLS signatures from validators, and delivers the signed messages to the destination chain.

How Relayers Work

When a cross-chain message is sent via TeleporterMessenger:

1. The message is emitted as a warp log on the source chain
2. The relayer detects the new message
3. It queries the validators of the source L1 for their BLS signatures
4. Once enough signatures are aggregated (meeting the threshold), the relayer constructs a signed warp message
5. The relayer submits a transaction on the destination chain to deliver the message
6. The destination TeleporterMessenger verifies the signatures and calls the receiving contract

Set Up a Hosted Relayer

We'll use a hosted relayer that requires no infrastructure on your part — perfect for testing. The relayer will automatically shut down after 3 days.

In the tool above:

1. Select Fuji C-Chain and your L1 as the networks to relay between
2. Create the hosted relayer (it will automatically start running)
3. Fund the relayer address with enough gas on both chains if needed