ethereum

README

Transaction Management Example

Demonstrates Turnkey's transaction management feature with both sponsored and non-sponsored modes.

Actions

• send — Self-transfer of 0.0001 ETH
• swap — Uniswap V3 swap (ETH → USDC) via SwapRouter02
• assets — List supported assets for the chain

The send and swap actions use Turnkey Gas Station for gas sponsorship by default. Pass -sponsor=false to use non-sponsored mode.

Prerequisites

• A Turnkey organization entitles to use the Transaction Management feature
• A wallet with Sepolia ETH
• A Turnkey API key (P-256)

Flags

Flag	Required	Default	Description
-api-private-key	Yes		Turnkey API private key
-organization-id	Yes		Turnkey organization ID
-sign-with	Yes		Wallet address to sign with (0x-prefixed)
-action	No	send	Action to perform: send, swap, or assets
-caip2	No	eip155:11155111	CAIP-2 chain ID
-sponsor	No	true	Use gas station sponsorship

Usage

# From go-sdk/examples/transaction_management/ethereum/

# Send 0.0001 ETH to self (sponsored)
go run main.go \
  -api-private-key "..." \
  -organization-id "..." \
  -sign-with "0x..." \
  -action send

# Swap 0.0001 ETH → USDC via Uniswap V3 (sponsored)
go run main.go \
  -api-private-key "..." \
  -organization-id "..." \
  -sign-with "0x..." \
  -action swap

# Send 0.0001 ETH to self (non-sponsored)
go run main.go \
  -api-private-key "..." \
  -organization-id "..." \
  -sign-with "0x..." \
  -sponsor=false \
  -action send

# Swap 0.0001 ETH → USDC via Uniswap V3 (non-sponsored)
go run main.go \
  -api-private-key "..." \
  -organization-id "..." \
  -sign-with "0x..." \
  -sponsor=false \
  -action swap

# List supported assets
go run main.go \
  -api-private-key "..." \
  -organization-id "..." \
  -sign-with "0x..." \
  -action assets

Example output

$ go run main.go -api-private-key ... -organization-id "7ff189fb-..." -sign-with "0xB2E8..." -action send
Balances for 0xB2E8...:
  0.05 ETH ($125.00)
  10.0 USDC ($10.00)

Action: send sponsored ETH self-transfer
Gas station nonce: 5
Transaction submitted, status ID: sha256:0e061f4b3fc0437e8c21dd7059ac05f6966af5d574456744cd48a6e22e2c40dd
Polling for confirmation...
  Status: INITIALIZED
Send complete! Tx hash: 0xda2a8c705f19d9f4e17ea354d213e50b7d38f76ccdce23f7c3492f87260e456d
Balances for 0xB2E8...:
  0.05 ETH ($125.00)
  10.0 USDC ($10.00)

$ go run main.go -api-private-key ... -organization-id "7ff189fb-..." -sign-with "0xB2E8..." -action swap
Balances for 0xB2E8...:
  0.05 ETH ($125.00)
  10.0 USDC ($10.00)

Action: swap ETH → USDC via Uniswap V3 (sponsored)
Gas station nonce: 6
Transaction submitted, status ID: sha256:bafb08367618c0e727c5b99f6ddc2f0cb05d5a81d723062af0cb8fc3c5018d08
Polling for confirmation...
  Status: INITIALIZED
Swap complete! Tx hash: 0xde41d1f35986f7f9a661afba568674d51a5913ba9f1c6d2391f99d6dd7a98e74
Balances for 0xB2E8...:
  0.0499 ETH ($124.75)
  10.05 USDC ($10.05)

How it works

1. Creates a Turnkey SDK client using the provided API key
2. Fetches and displays wallet balances via GetWalletAddressBalances
3. Sponsored mode (-sponsor=true, default): fetches a gas station nonce via GetNonces for transaction ordering and replay protection
4. Non-sponsored mode (-sponsor=false): Turnkey resolves the on-chain nonce automatically
5. Submits the transaction via EthSendTransaction
6. Polls GetSendTransactionStatus until a tx hash is returned or an error occurs
7. Fetches and displays updated balances to show the difference

For the swap action, the calldata is ABI-encoded for Uniswap V3 SwapRouter02's exactInputSingle (selector 0x04e45aaf), targeting the WETH/USDC pool with a 0.3% fee tier on Sepolia.

Nonce handling

There are two distinct nonces involved in transaction management:

• On-chain nonce — the standard Ethereum transaction nonce. Turnkey resolves this automatically in both sponsored and non-sponsored modes; you never need to provide it. If you want to manage it yourself, you can fetch it via GetNonces with Nonce: true and set intent.Nonce (see example below). Custom on-chain nonces are not compatible with sponsored transactions.

• Gas station nonce — a nonce specific to the gas station delegate contract, only relevant for sponsored transactions (sponsor: true). Turnkey handles this internally if omitted, but passing it explicitly provides maximal security against replay attacks: it ensures a signed request can only produce a single transaction. See the Gas Station security docs. This example passes it explicitly.

Providing a custom on-chain nonce

params := broadcasting.NewGetNoncesParams().WithBody(&models.GetNoncesRequest{
    OrganizationID: &organizationID,
    Address:        &signWith,
    Caip2:          &caip2,
    Nonce:          true,
})

resp, err := client.V0().Broadcasting.GetNonces(params, client.Authenticator)
if err != nil {
    return err
}

intent.Nonce = resp.Payload.Nonce

Note: if you run multiple sponsored transactions back-to-back, wait for the previous one to confirm before sending the next — otherwise the gas station nonce may not have incremented yet, causing an InvalidNonce error.