Backend overview

Backend for caching transmissions and helping the sdk work smoother with the Teleport Protocol. The backend periodically obtains data and cache it into redis, by applying one or more of the following methods:

• Polling from validator endpoints for new Transmissions, Signatures and Deliveries.
• Listening to events triggered by CCIP-related contracts.

It also exposes endopints for the Bridge SDK to:

• get claims for a certain receiver
• estimate delivery fee

Claims endpoint

Nexera Backend exposes an endpoint that looks like this

/{dAppId}/claims?targetChainId=...&receiver=...

• {dAppId} can be either erc20 or erc721
• receiver is the address we are fetching the claims for
• targetChainId is the ABridge id of the target chain we are fetching claims for

The response is a list of claims, each with the following parameters

[
  {
    dAppId: ...,
    transmissionId: ...,
    transmissionBlock: ...,
    transmissionTxHash: ...,
    transmissionTxTimestamp: ...,
    transmissionSender: ...,
    transmissionReceiver: ...,
    targetChainId: ...,
    payload: ...,
    parsedPayload: {...},
    sourceChainId: ...,
    signatures: [ ... ],
    majorityReached: ...,
    delivery: {
      transmissionId: ...,
      deliveryBlock: ...,
      deliveryTxHash: ...,
      deliveryTxTimestamp: ...
    }
  },
...
]

• parsedPayload contains a dApp-specific subset of parameters extracted from the payload for erc20 it looks like

parsedPayload: {
  type: "erc20",
  receiver: ...,
  deliveryFee: {
    type: "BigNumber",
    hex: ...
  }
}

for erc721 it looks like

parsedPayload: {
  type: "erc721",
  receiver: ...,
}

Delivery fee estimation endpoint

ABridge Backend's delivery estimation endpoint looks like this

/erc20/estimateDeliveryFee?sourceChainId=...&targetChainId=...&token=...&amount=...&sender=...&receiver=...

Currently only available for ERC20 Bridge.

• token is the address of the token being bridge - the backend need this to figure out of a new Wrapped Token will be deployed on claim, or one already exists.
• amount is the ETH value to bridge, e.g. 0.1337
• sender and receiver are the corresponding addresses.

On success, the response is:

{
  fee: ...,
  expiry: ...,
  signature: ...
}

All three parameters should be passed to ERC20Bridge.egress, as DeliveryFeeData, e.g. '[$fee, $expiry, $signature]'