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Add Liquidity to Across HubPool with ETH

This is a more advanced action that uses the resulting ETH balance for both a function argument and the transaction's value. The addLiquidity function requires the amount of ETH as an argument. We dynamically provide this by setting populateDynamically: true and using the zero address (0x00...00) for balanceSource, which signifies the native ETH balance. When an argument is populated dynamically from the native balance, the value of the transaction is automatically and implicitly set to that same amount, streamlining the process.

Request Body

{
  "actions": [
    {
      "target": "0xc186fA914353c44b2E33eBE05f21846F1048bEda",
      "functionSignature": "function addLiquidity(address l1Token, uint256 l1TokenAmount)",
      "args": [
        {
          "value": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
          "populateDynamically": false
        },
        {
          "value": "0",
          "populateDynamically": true,
          "balanceSourceToken": "0x0000000000000000000000000000000000000000"
        }
      ],
      "value": "0",
      "isNativeTransfer": false,
      "populateCallValueDynamically": true
    }
  ]
}

Request approval & execution plan for crosschain swap

post

Given input/output tokens, chain IDs, depositor/recipient, and post-bridge actions, this endpoint returns:

  • Allowance & balance checks

  • Approval transaction(s) if required

  • Swap and bridge execution steps

  • Final transaction payload (swapTx)

  • Fees breakdown

Query parameters
tradeTypestring · enumRequiredExample: exactInputPossible values:
amountstringRequired

Trade amount in smallest units (e.g., USDC 6 decimals).

Example: 10000000
inputTokenstringRequired

Address of token to swap from (checksummed).

Example: 0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85
outputTokenstringRequired

Address of token to swap to (checksummed).

Example: 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2
originChainIdstringRequired

Chain ID where swap originates.

Example: 10
destinationChainIdstringRequired

Chain ID where swap finalizes.

Example: 1
depositorstringRequired

EVM address of depositor.

Example: 0xA4d353BBc130cbeF1811f27ac70989F9d568CeAB
recipientstringRequired

EVM address of recipient after bridging.

Example: 0xA4d353BBc130cbeF1811f27ac70989F9d568CeAB
Body
Responses
200

Successful swap approval response

application/json
post
POST /api/swap/approval HTTP/1.1
Host: app.across.to
Content-Type: application/json
Accept: */*
Content-Length: 425

{
  "actions": [
    {
      "target": "0xc186fA914353c44b2E33eBE05f21846F1048bEda",
      "functionSignature": "function addLiquidity(address l1Token, uint256 l1TokenAmount)",
      "args": [
        {
          "value": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
          "populateDynamically": false
        },
        {
          "value": "0",
          "populateDynamically": true,
          "balanceSourceToken": "0x0000000000000000000000000000000000000000"
        }
      ],
      "value": "0",
      "isNativeTransfer": false,
      "populateCallValueDynamically": true
    }
  ]
}
{
  "crossSwapType": "anyToBridgeable",
  "amountType": "exactInput",
  "checks": {
    "allowance": {
      "token": "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85",
      "spender": "0x89415a82d909a7238d69094C3Dd1dCC1aCbDa85C",
      "actual": "0",
      "expected": "10000000"
    },
    "balance": {
      "token": "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85",
      "actual": "169942",
      "expected": "10000000"
    }
  },
  "approvalTxns": [
    {
      "chainId": 10,
      "to": "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85",
      "data": "0x095ea7b300000000000000000000000089415a82d909a7238d69094c3dd1dcc1acbda85cffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
    }
  ],
  "steps": {
    "originSwap": {
      "tokenIn": {
        "decimals": 6,
        "symbol": "USDC",
        "address": "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85",
        "name": "USD Coin",
        "chainId": 10
      },
      "tokenOut": {
        "address": "0x4200000000000000000000000000000000000006",
        "decimals": 18,
        "symbol": "ETH",
        "chainId": 10
      },
      "inputAmount": "10000000",
      "outputAmount": "2070607856240202",
      "minOutputAmount": "2049901777677600",
      "maxInputAmount": "10000000",
      "swapProvider": {
        "name": "0x",
        "sources": [
          "uniswap_v4",
          "uniswap_v3",
          "velodrome_v3"
        ]
      }
    },
    "bridge": {
      "inputAmount": "2049901777677600",
      "outputAmount": "1942640017359211",
      "tokenIn": {
        "address": "0x4200000000000000000000000000000000000006",
        "decimals": 18,
        "symbol": "ETH",
        "chainId": 10
      },
      "tokenOut": {
        "address": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
        "decimals": 18,
        "symbol": "ETH",
        "name": "Ether",
        "chainId": 1
      },
      "fees": {
        "totalRelay": {
          "pct": "52325316991485989",
          "total": "107261760318389"
        },
        "relayerCapital": {
          "pct": "99914587425765",
          "total": "204815090379"
        },
        "relayerGas": {
          "pct": "52034031578669020",
          "total": "106664653832845"
        },
        "lp": {
          "pct": "191370825391204",
          "total": "392291395165"
        }
      }
    }
  },
  "inputToken": {
    "decimals": 6,
    "symbol": "USDC",
    "address": "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85",
    "name": "USD Coin",
    "chainId": 10
  },
  "outputToken": {
    "decimals": 18,
    "symbol": "ETH",
    "address": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
    "name": "Ether",
    "chainId": 1
  },
  "refundToken": {
    "address": "0x4200000000000000000000000000000000000006",
    "decimals": 18,
    "symbol": "WETH",
    "chainId": 10
  },
  "fees": {
    "total": {
      "amount": "600687",
      "amountUsd": "0.60050966243367121",
      "pct": "60068746592358460",
      "token": {
        "decimals": 6,
        "symbol": "USDC",
        "address": "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85",
        "name": "USD Coin",
        "chainId": 10
      }
    },
    "originGas": {
      "amount": "0",
      "amountUsd": "0.0",
      "token": {
        "chainId": 10,
        "address": "0x0000000000000000000000000000000000000000",
        "decimals": 18,
        "symbol": "ETH"
      }
    },
    "destinationGas": {
      "amount": "106664653832845",
      "amountUsd": "0.515774800315645265",
      "pct": "51592751486004382",
      "token": {
        "chainId": 1,
        "address": "0x0000000000000000000000000000000000000000",
        "decimals": 18,
        "symbol": "ETH"
      }
    },
    "relayerCapital": {
      "amount": "204815090379",
      "amountUsd": "0.000990379273225847",
      "pct": "99067251228948",
      "token": {
        "address": "0x4200000000000000000000000000000000000006",
        "decimals": 18,
        "symbol": "ETH",
        "chainId": 10
      }
    },
    "lpFee": {
      "amount": "392291395165",
      "amountUsd": "0.001896917195492454",
      "pct": "189747884923183",
      "token": {
        "address": "0x4200000000000000000000000000000000000006",
        "decimals": 18,
        "symbol": "ETH",
        "chainId": 10
      }
    },
    "relayerTotal": {
      "amount": "107261760318389",
      "amountUsd": "0.518662096784363591",
      "pct": "51881566622156518",
      "token": {
        "address": "0x4200000000000000000000000000000000000006",
        "decimals": 18,
        "symbol": "ETH",
        "chainId": 10
      }
    },
    "app": {
      "amount": "0",
      "amountUsd": "0.0",
      "pct": "0",
      "token": {
        "decimals": 18,
        "symbol": "ETH",
        "address": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
        "name": "Ether",
        "chainId": 1
      }
    }
  },
  "inputAmount": "10000000",
  "expectedOutputAmount": "1942640017359211",
  "minOutputAmount": "1942640017359211",
  "expectedFillTime": 8,
  "swapTx": {
    "simulationSuccess": false,
    "chainId": 10,
    "to": "0x89415a82d909a7238d69094C3Dd1dCC1aCbDa85C",
    "data": "0x110560ad0000000000000000000000000000000000000000000000000000000000000020...",
    "maxFeePerGas": "1002808",
    "maxPriorityFeePerGas": "1000000"
  },
  "id": "2mcw2-1755906874198-a000ed7c7701"
}
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