# Accelerate Transactions

Source: https://developers.bitgo.com/docs/withdraw-accelerate

## Overview

During periods of high transaction volume, transactions with lower fees might get stuck waiting for confirmation in the mempool. If this happens, you can accelerate the transaction by creating a new transaction with a higher fee. The new transaction replaces the original in the mempool and has a higher probability of miners confirming it more quickly, since economic incentives drive miners and validators.

Transaction acceleration differs between UTXO and account-based assets.

You can subscribe to the `stuckTx` wallet webhook to receive notifications when a transaction becomes stuck. For more information, see [Create Wallet Webhooks](/docs/webhooks-wallet).

## Cookbooks

Need just the steps? Expand a cookbook below to get started:

### Account-Based

<Cookbook slug="accelerate-transaction-account-based-curl" title="Accelerate Account-Based" />

### UTXO

<Cookbook slug="accelerate-transaction-utxo-cpfp" title="Accelerate - UTXO (CPFP)" />

<Cookbook slug="accelerate-transaction-utxo-rbf" title="Accelerate - UTXO (RBF)" />

<Tabs>
<Tab title="Account-Based Assets">
Ethereum, and other EVM blockchains, allow for only one transaction per nonce from a single address. A nonce is a sequential counter for transactions sent from an account. Therefore, you can accelerate a stuck transaction by rebroadcasting the same transaction with the same nonce but with a higher fee.

## Prerequisites

* [Get Started](/docs/get-started-intro)
* Initiate a withdrawal (see [Withdraw Overview](/docs/withdraw-overview)).

## Build Acceleration Transaction

>Endpoints:
>
>* [Initiate a transaction](/reference/v2wallettxinitiate)
>* [Create transaction request](/reference/v2wallettxrequestcreate)
>* [Build a transaction](/reference/v2wallettxbuild)

```shell cURL (Custody Multisig)
export COIN="<ASSET_ID>"
export WALLET_ID="<YOUR_WALLET_ID>"
export ACCESS_TOKEN="<YOUR_ACCESS_TOKEN>"
export NONCE="<NONCE_OF_STUCK_TRANSACTION>"
export MAX_FEE_PER_GAS="<HIGHER_MAX_FEE_PER_GAS>"
export MAX_PRIORITY_FEE_PER_GASE="<HIGHER_MAX_PRIORITY_FEE_PER_GAS>"

curl -X POST \
  https://app.bitgo-test.com/api/v2/$COIN/wallet/$WALLET_ID/tx/initiate \
  -H 'Content-Type: application/json' \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -d '{
    "type": "acceleration",
    "nonce": "'"$NONCE"'",
    "eip1559": {
      "maxFeePerGas": "'"$MAX_FEE_PER_GAS"'",
      "maxPriorityFeePerGas": "'"$MAX_PRIORITY_FEE_PER_GASE"'"
  },
    "recipients": [...] # Use the exact recipients array from the original transaction
  }'
```
```shell cURL (Custody MPC)
export WALLET_ID="<WALLET_ID>"
export ACCESS_TOKEN="<YOUR_ACCESS_TOKEN>"
export MAX_FEE_PER_GAS="<HIGHER_MAX_FEE_PER_GAS>"
export MAX_PRIORITY_FEE_PER_GASE="<HIGHER_MAX_PRIORITY_FEE_PER_GAS>"
export NONCE="<NONCE_OF_STUCK_TRANSACTION>"

curl -X POST \
  https://app.bitgo-test.com/api/v2/wallet/$WALLET_ID/txrequests \
  -H 'Content-Type: application/json' \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -d '{
  "idempotencyKey": "string",
  "intent": {
    "feeOptions": {
      "gasLimit": 0,
      "maxFeePerGas": "'"$MAX_FEE_PER_GAS"'",
      "maxPriorityFeePerGas": "'"$MAX_PRIORITY_FEE_PER_GASE"'"
    },
    "intentType": "acceleration",
    "txid": "string",
    "sequenceId": "string",
    "nonce": "'"$NONCE"'",
    "hopParams": {
      "gasPriceMax": 0,
      "paymentId": "string",
      "userReqSig": "string"
    },
    "receiveAddress": "string",
    "senderAddressIndex": 0
  },
  "videoApprovers": [
    "585951a5df8380e0e3063e9f",
    "585951a5df8380e0e304a553"
  ],
  "apiVersion": "lite",
  "preview": false
}'
```
```shell cURL (Self-Custody MPC)
export WALLET_ID="<WALLET_ID>"
export ACCESS_TOKEN="<YOUR_ACCESS_TOKEN>"
export MAX_FEE_PER_GAS="<HIGHER_MAX_FEE_PER_GAS>"
export MAX_PRIORITY_FEE_PER_GASE="<HIGHER_MAX_PRIORITY_FEE_PER_GAS>"
export NONCE="<NONCE_OF_STUCK_TRANSACTION>"

curl -X POST \
  https://app.bitgo-test.com/api/v2/wallet/$WALLET_ID/txrequests \
  -H 'Content-Type: application/json' \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -d '{
  "idempotencyKey": "string",
  "intent": {
    "feeOptions": {
      "gasLimit": 0,
      "maxFeePerGas": "'"$MAX_FEE_PER_GAS"'",
      "maxPriorityFeePerGas": "'"$MAX_PRIORITY_FEE_PER_GASE"'"
    },
    "intentType": "acceleration",
    "txid": "string",
    "sequenceId": "string",
    "nonce": "'"$NONCE"'",
    "hopParams": {
      "gasPriceMax": 0,
      "paymentId": "string",
      "userReqSig": "string"
    },
    "receiveAddress": "string",
    "senderAddressIndex": 0
  },
  "videoApprovers": [
    "585951a5df8380e0e3063e9f",
    "585951a5df8380e0e304a553"
  ],
  "apiVersion": "lite",
  "preview": false
}'
```
```shell cURL (Self-Custody Multisig)
export COIN="<ASSET_ID>"
export WALLET_ID="<WALLET_ID>"
export ACCESS_TOKEN="<YOUR_ACCESS_TOKEN>"
export NONCE="<NONCE_OF_STUCK_TRANSACTION>"
export MAX_FEE_PER_GAS="<HIGHER_MAX_FEE_PER_GAS>"
export MAX_PRIORITY_FEE_PER_GASE="<HIGHER_MAX_PRIORITY_FEE_PER_GAS>"

curl -X POST \
  https://app.bitgo-test.com/api/v2/$COIN/wallet/$WALLET_ID/tx/build \
  -H 'Content-Type: application/json' \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -d '{
    "type": "acceleration",
    "nonce": "'"$NONCE"'",
    "eip1559": {
      "maxPriorityFeePerGas": "'"$MAX_FEE_PER_GAS"'",
      "maxPriorityFeePerGas": "'"$MAX_PRIORITY_FEE_PER_GASE"'"
    },
    "recipients": [...], # Use the exact recipients array from the original transaction
  }'
```

#### Step Result

```json JSON
{
  "txRequestId": "string",
  "version": 0,
  "latest": true,
  "walletId": "string",
  "walletType": "cold",
  "enterpriseId": "string",
  "state": "initialized",
  "date": {},
  "createdDate": {},
  "userId": "string",
  "initiatedBy": "string",
  "updatedBy": "string",
  "intent": {
    "feeOptions": {
      "unit": "baseUnit",
      "formula": "fixed",
      "feeType": "base",
      "gasLimit": 0,
      "gasPrice": 0
    },
    "intentType": "acceleration",
    "txid": "string",
    "sequenceId": "string",
    "comment": "string",
    "nonce": "string",
    "hopParams": {
      "gasPriceMax": 0,
      "paymentId": "string",
      "userReqSig": "string"
    },
    "receiveAddress": "string",
    "senderAddressIndex": 0
  },
  "intents": [
    {
      "intentType": "stake",
      "sequenceId": "abc123",
      "comment": "string",
      "nonce": "string",
      "memo": "string",
      "stakingRequestId": "string",
      "poolKeyHash": "string"
    }
  ],
  "pendingApprovalId": "string",
  "isCanceled": true,
  "unsignedTxs": [
    {
      "serializedTxHex": "string",
      "signableHex": "string",
      "derivationPath": "string",
      "feeInfo": {
        "feeString": "string",
        "fee": 0
      },
      "coinSpecific": {},
      "parsedTx": {
        "minerFee": "string",
        "spendAmount": "string",
        "spendAmounts": [
          {
            "coinName": "string",
            "amountString": "string"
          }
        ],
        "payGoFee": "string",
        "outputs": [
          {
            "address": "string",
            "isPayGo": true,
            "value": 0,
            "wallet": "string",
            "walletV1": "string",
            "baseAddress": "string",
            "enterprise": "string",
            "valueString": "string",
            "data": "string",
            "change": true,
            "coinName": "string"
          }
        ],
        "inputs": [
          {
            "derivationIndex": 0,
            "value": 0,
            "address": "string",
            "valueString": "string",
            "chain": 0,
            "index": 0
          }
        ],
        "type": "string",
        "memo": "string"
      }
    }
  ],
  "signatureShares": [
    {
      "from": "user",
      "to": "user",
      "share": "string"
    }
  ],
  "commitmentShares": [
    {
      "from": "user",
      "to": "user",
      "share": "string",
      "type": "commitment"
    }
  ],
  "txHashes": [
    "string"
  ]
}
```
</Tab>
<Tab title="UTXO Assets">
<br></br>
You have two options to accelerate a stuck UTXO transaction:

1. **Replace-By-Fee (RBF)** - RBF transactions include a higher fee and replace the lower-fee stuck transaction. To learn more, see the concept topic, [Replace-By-Fee (RBF)](/docs/rbf).
1. **Child-Pays-For-Parent (CPFP)** - CPFP transactions utilize a stuck transaction output of a lower-fee parent transaction to create a higher-fee child transaction. The network must confirm the parent transaction before the child transaction. Therefore, miners likely include both in the same block.

> 📘 **Note:** BitGo recommends accelerating using RBF, and by default, enables RBF for all transactions created in the BitGo web application.

## Prerequisites

* [Get Started](/docs/get-started-intro)
* To accelerate using RBF, ensure you built your initial transaction with `isReplaceableByFee` set to `true`. To learn more, see [Withdraw Overview](/docs/withdraw-overview).

## Build Acceleration Transaction

>Endpoint: [Accelerate Transaction](/reference/expresswalletacceleratetx)

```shell cURL (RBF)
export COIN="<ASSET_ID>"
export WALLET_ID="<YOUR_WALLET_ID>"
export ACCESS_TOKEN="<YOUR_ACCESS_TOKEN>"
export TRANSACTION_ID="<STUCK_TX_ID>"
export FEE_MULTIPLIER="<FEE_MULTIPLIER>"

curl -X POST \
  "http://$BITGO_EXPRESS_HOST/api/v2/$COIN/wallet/$WALLET_ID/acceleratetx" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -d '{
    "rbfTxIds": ["'"$TRANSACTION_ID"'"],
    "feeMultiplier": "'"$FEE_MULTIPLIER"'"
  }'
```
```shell cURL (CPFP)
export COIN="<ASSET_ID>"
export WALLET_ID="<YOUR_WALLET_ID>"
export ACCESS_TOKEN="<YOUR_ACCESS_TOKEN>"
export TRANSACTION_ID="<STUCK_TX_ID>"
export FEE_RATE="<FEE_RATE>"
export MAX_FEE="<MAX_FEE>"

curl -X POST \
  "http://$BITGO_EXPRESS_HOST/api/v2/$COIN/wallet/$WALLET_ID/acceleratetx" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -d '{
    "cpfpTxIds": ["'"$TRANSACTION_ID"'"],
    "cpfpFeeRate": "'"$FEE_RATE"'",
    "maxFee": "'"$MAX_FEE"'"
  }'
```

#### Step Result

```json JSON
{
  "transfer": {
    "coin": "btc",
    "id": "59cd72485007a239fb00282ed480da1f",
    "wallet": "59cd72485007a239fb00282ed480da1f",
    "enterprise": "59cd72485007a239fb00282ed480da1f",
    "txid": "b8a828b98dbf32d9fd1875cbace9640ceb8c82626716b4a64203fdc79bb46d26",
    "txidType": "transactionHash",
    "height": 0,
    "heightId": "string",
    "date": "2019-08-24T14:15:22Z",
    "confirmations": 0,
    "type": "send",
    "value": 0,
    "valueString": "2000000",
    "intendedValueString": "2000000",
    "baseValue": 0,
    "baseValueString": "2000000",
    "baseValueWithoutFees": 0,
    "baseValueWithoutFeesString": "2000000",
    "feeString": "string",
    "payGoFee": 0,
    "payGoFeeString": "string",
    "usd": 0,
    "usdRate": 0,
    "state": "confirmed",
    "tags": [
      "59cd72485007a239fb00282ed480da1f"
    ],
    "history": [
      {
        "date": "2019-08-24T14:15:22Z",
        "user": "59cd72485007a239fb00282ed480da1f",
        "action": "created",
        "comment": "string"
      }
    ],
    "comment": "string",
    "vSize": 0,
    "coinSpecific": {},
    "sequenceId": "string",
    "entries": [
      {
        "address": "2NAUwNgXaoFj2VVnSEvNLGuez8CfdU2UCMZ",
        "wallet": "string",
        "value": 0,
        "valueString": "string",
        "isChange": true,
        "isPayGo": true,
        "token": "omg",
        "label": "string",
        "failed": true
      }
    ],
    "usersNotified": true,
    "label": "string",
    "replaces": [
      "string"
    ],
    "replacedBy": [
      "string"
    ]
  },
  "txid": "string",
  "tx": "string",
  "status": "signed"
}
```
</Tab>
</Tabs>

## Next

Acceleration transactions follow the transaction flow of their wallet type, and must receive all required signatures and approvals before before broadcasting to the blockchain. To learn more, see [Withdraw Overview](/docs/withdraw-overview)

After receiving all required signatures and approvals, BitGo broadcasts the transaction to the blockchain. You can view your completed transaction in BitGo or on a blockchain explorer. For UTXO assets, the blockchain explorer may also identify the transaction with an RBF or CPFP flag. Once the network confirms your accelerated transaction on chain, BitGo updates the status of the original transaction to `Replaced`.

## See Also

* [API Reference: Accelerate Transaction](/reference/expresswalletacceleratetx)
* [API Reference: Build a Transaction](/reference/v2wallettxbuild)
* [API Reference: Send Transaction](/reference/expresswalletsendcoins)
* [Concept: Replace-By-Fee (RBF)](/docs/rbf)
* [Withdraw Overview](/docs/withdraw-overview)
* [Create Wallet Webhooks](/docs/webhooks-wallet)