Send transactions with Swift - Polygon Developer Docs

Transaction writes require an active wallet session. sendTransaction and callContract are alternate inputs to one lifecycle: prepare, resolve any fee requirement, execute, and wait for status by default.

Send native value

Amounts are raw base-unit integer strings. Use parseUnits to convert display values without floating-point arithmetic.

let value = try parseUnits(value: "0.01", decimals: 18)

let transaction = try await omsWallet.wallet.sendTransaction(
    network: .polygonAmoy,
    to: "0x1111111111111111111111111111111111111111",
    value: value
)

print(transaction.txnId)
print(transaction.txnHash ?? "Hash not available yet")

The default transaction mode is .relayer, and waitForStatus defaults to true.

Send encoded calldata

Use SendTransactionRequest when you already have calldata. value remains a raw base-unit string.

let transaction = try await omsWallet.wallet.sendTransaction(
    network: .polygonAmoy,
    request: SendTransactionRequest(
        to: "0x2222222222222222222222222222222222222222",
        value: "0",
        data: "0xa9059cbb000000000000000000000000111111111111111111111111111111111111111100000000000000000000000000000000000000000000000000000000000f4240"
    )
)

parseUnits defaults to 18 decimals and rounds excess fractional precision to the nearest base unit. Invalid values and negative decimal counts throw UnitConversionError.

Call an ABI method

Use callContract when you have a method signature and typed arguments instead of encoded calldata.

let amount = try parseUnits(value: "1", decimals: 6)

let transaction = try await omsWallet.wallet.callContract(
    network: .polygonAmoy,
    contract: "0x2222222222222222222222222222222222222222",
    method: "transfer(address,uint256)",
    args: [
        AbiArg(
            type: "address",
            value: .string("0x1111111111111111111111111111111111111111")
        ),
        AbiArg(type: "uint256", value: .string(amount))
    ]
)

Both forms prepare and execute through the same fee and status code path.

Resolve fees during preparation

Preparation tells the SDK whether the transaction is sponsored. Sponsored preparations execute without a fee selection. An unsponsored preparation must include fee options. Testnet transaction fees are sponsored. On mainnet, the preparation response may instead require fee selection. With no selector, the SDK chooses the first fee option returned by OMS. This default does not compare the option with the wallet’s balance. Use .firstAvailable to query indexer balances and choose the first option whose raw available balance covers its quoted fee.

let transaction = try await omsWallet.wallet.sendTransaction(
    network: .polygon,
    to: "0x1111111111111111111111111111111111111111",
    value: "0",
    selectFeeOption: .firstAvailable
)

Use a custom selector when your UI or policy chooses the fee token.

let transaction = try await omsWallet.wallet.sendTransaction(
    network: .polygon,
    to: "0x1111111111111111111111111111111111111111",
    value: "0",
    selectFeeOption: .custom { options in
        options.first { $0.feeOption.token.symbol == "USDC" }?.selection
    }
)

FeeOptionWithBalance.availableRaw is the base-unit balance used for comparison. available is formatted for display when token decimals are known.

These fee-selection examples use Polygon mainnet. Fund the wallet for any returned fee option your app selects.

Interpret the result

SendTransactionResponse always contains the OMS txnId, the latest status, and statusResolution. txnHash is optional until an onchain hash is available.

Resolution	Meaning
`.resolved`	Polling observed `.executed`, `.failed`, or an onchain transaction hash. A hash can resolve a response whose latest status is still `.pending`.
`.timedOut`	The polling deadline elapsed. The response contains the last status and hash observed. The transaction may continue.
`.notRequested`	`waitForStatus` was `false`, so the SDK returned the execute response without polling.

A resolved result can still have status == .failed. Check both status and resolution.

Return after execution

Set waitForStatus: false when your app wants to persist txnId immediately after the execute call and manage status separately.

let submitted = try await omsWallet.wallet.sendTransaction(
    network: .polygonAmoy,
    to: "0x1111111111111111111111111111111111111111",
    value: "0",
    waitForStatus: false
)

let status = try await omsWallet.wallet.getTransactionStatus(
    txnId: submitted.txnId
)

getTransactionStatus also requires the active wallet session and credential. To change the default wait, pass TransactionStatusPollingOptions. The SDK defaults to a 60-second timeout, uses short initial intervals, and then polls every two seconds.

let transaction = try await omsWallet.wallet.sendTransaction(
    network: .polygonAmoy,
    to: "0x1111111111111111111111111111111111111111",
    value: "0",
    statusPolling: TransactionStatusPollingOptions(
        timeoutMs: 120_000,
        intervalMs: 3_000
    )
)

Handle uncertain execution and cancellation

The SDK preserves CancellationError instead of wrapping it. Cancelling a Swift task stops the local SDK operation or status wait. It does not cancel a transaction that may already have been submitted. When your UI needs a cancellable wait with a durable identifier, submit with waitForStatus: false, persist txnId, and poll in a separate task. Transaction-specific OMSWalletError codes carry recovery context:

do {
    _ = try await omsWallet.wallet.sendTransaction(
        network: .polygonAmoy,
        to: "0x1111111111111111111111111111111111111111",
        value: "0"
    )
} catch is CancellationError {
    // Do not assume cancellation reversed a submitted transaction.
} catch let error as OMSWalletError {
    switch error.code {
    case .transactionExecutionUnconfirmed:
        // Preparation produced txnId, but submission could not be confirmed.
        print("Execution unconfirmed:", error.txnId ?? "unknown")
    case .transactionStatusLookupFailed:
        // Execution was submitted. Retry status lookup with txnId.
        print("Retry status lookup:", error.txnId ?? "unknown")
    default:
        throw error
    }
}

Do not automatically resend after .transactionExecutionUnconfirmed; the original transaction may have been submitted.

​Send native value

​Send encoded calldata

​Call an ABI method

​Resolve fees during preparation

​Interpret the result

​Return after execution

​Handle uncertain execution and cancellation

Send native value

Send encoded calldata

Call an ABI method

Resolve fees during preparation

Interpret the result

Return after execution

Handle uncertain execution and cancellation