Ethclient.go: How to send an EIP-1559 transaction

Hi everyone,

If you’re using Go, check out this pretty good guide about how to interact with Ethereum. In particular, this example shows how to send a legacy transaction but there isn’t anything for EIP-1559 tx type, so here it is:

Prerequisites

• Download and install Go Download and install - The Go Programming Language 3

• If this is your first Go script (let’s call it eip1559_tx.go), follow the steps here How to Write Go Code - The Go Programming Language 7

• Replace the API KEY and ADDRESS_TO with your relevant values

• Run the script with: go run eip1559_tx.go

• Expected response: Transaction hash: 0x...

Code

package main

import (
	"context"
	"crypto/ecdsa"
	"fmt"
	"log"
	"math/big"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/ethclient"
)

func main() {
	client, err := ethclient.Dial("https://ropsten.infura.io/v3/PROJECT_ID")
	if err != nil {
		log.Fatal(err)
	}

	privateKey, err := crypto.HexToECDSA("PRIVATE_KEY")
	if err != nil {
		log.Fatal(err)
	}

	publicKey := privateKey.Public()
	publicKeyECDSA, ok := publicKey.(*ecdsa.PublicKey)
	if !ok {
		log.Fatal("error casting public key to ECDSA")
	}

	fromAddress := crypto.PubkeyToAddress(*publicKeyECDSA)

	nonce, err := client.PendingNonceAt(context.Background(), fromAddress)
	if err != nil {
		log.Fatal(err)
	}

	value := big.NewInt(100000000000000000) // in wei (0.1 eth)
	gasLimit := uint64(21000)               // in units
	tip := big.NewInt(2000000000)           // maxPriorityFeePerGas = 2 Gwei
	feeCap := big.NewInt(20000000000)       // maxFeePerGas = 20 Gwei
	if err != nil {
		log.Fatal(err)
	}

	toAddress := common.HexToAddress("ADDRESS_TO")
	var data []byte

	chainID, err := client.NetworkID(context.Background())
	if err != nil {
		log.Fatal(err)
	}

	tx := types.NewTx(&types.DynamicFeeTx{
		ChainID:   chainID,
		Nonce:     nonce,
		GasFeeCap: feeCap,
		GasTipCap: tip,
		Gas:       gasLimit,
		To:        &toAddress,
		Value:     value,
		Data:      data,
	})

	signedTx, err := types.SignTx(tx, types.LatestSignerForChainID(chainID), privateKey)

	if err != nil {
		log.Fatal(err)
	}

	err = client.SendTransaction(context.Background(), signedTx)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Printf("Transaction hash: %s", signedTx.Hash().Hex())

}