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This example demonstrates the basic usage of the CCTP Go SDK, including getting available chains, creating an Iris client, and polling for attestations.

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What This Example Demonstrates

  • Getting available chains for mainnet or testnet
  • Creating an Iris client for attestation polling
  • Polling for attestations using a burn transaction hash
  • Basic error handling

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Complete Code Example

This is the exact example from the SDK README showing the fundamental usage: 
package main

import (
    "context"
    "fmt"
    "math/big"

    "github.com/ethereum/go-ethereum/common"
    "github.com/circlefin/cctp-go"
)

func main() {
    // Get available chains
    chains := cctp.GetChains(false) // false = mainnet

    // Create an Iris client for attestations
    irisClient := cctp.NewIrisClient("https://iris-api.circle.com")

    // Poll for an attestation
    ctx := context.Background()
    msg, err := irisClient.PollForAttestation(
        ctx,
        0, // source domain (Ethereum)
        "0x...", // burn transaction hash
        nil, // optional progress callback
    )
    if err != nil {
        panic(err)
    }

    fmt.Printf("Attestation received: %s\n", msg.Attestation)
}

​
Breaking Down the Example

1

Get Available Chains

Use GetChains(false) to retrieve all mainnet chains. Pass true for testnet chains:
chains := cctp.GetChains(false) // false = mainnet
testnetChains := cctp.GetChains(true) // true = testnet
The chains slice contains all supported CCTP chains with their configuration including RPC endpoints, contract addresses, and domain IDs.
2

Create an Iris Client

The IrisClient is used to fetch attestations from Circle’s Iris API:
irisClient := cctp.NewIrisClient("https://iris-api.circle.com")
For testnet, use: https://iris-api-sandbox.circle.com
3

Poll for Attestation

Use the PollForAttestation method to wait for an attestation to be ready:
ctx := context.Background()
msg, err := irisClient.PollForAttestation(
    ctx,
    0,       // source domain (Ethereum = 0)
    "0x...", // burn transaction hash
    nil,     // optional progress callback
)
The method will automatically retry with exponential backoff until the attestation is ready.
4

Handle the Result

Once the attestation is received, you can access various fields:
if err != nil {
    panic(err)
}

fmt.Printf("Attestation: %s\n", msg.Attestation)
fmt.Printf("Message: %s\n", msg.Message)
fmt.Printf("Status: %s\n", msg.Status)
The progress callback parameter is optional. See Attestation Polling for an example with progress tracking.

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Chain Domains

Common domain IDs you’ll use:
ChainDomain
Ethereum0
Avalanche1
OP Mainnet2
Arbitrum3
Base6
Polygon PoS7
See the Supported Chains page for the complete list.

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Next Steps

Chain Configuration

Learn about chain configurations and helper functions

Iris Client

Explore the Iris client for attestation management

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