Approve token allowence

Execution Scope (Single-hop vs Multihop)

/public/emigroswap/buildTransaction returns a fully-formed single-hop transaction, including:

• routerAddress

• abiFunctionSignature

• abiParameters

• adapterAddress

• adapterData

• amountOut (RAW) and minAmountIn (RAW)

What’s supported internally (multihop): Your backend service already supports multihop execution via swapExactInputPathVia(...) when an intent is created and executed by the server. That flow is internal today.

Planned/optional (future public multihop): If/when you expose multihop via the public buildTransaction, the response will mirror the single-hop shape and include:

• routerAddress

• abiFunctionSignature: "swapExactInputPathVia(address,address[],uint256,uint256,address,bytes)"

• abiParameters (with path and per-hop adapterData encoded)

Until that is exposed, external callers should use single-hop buildTransaction responses as-is.

If you need for refference, you can check in API REFERENCE the correct smartcontract router address in the correct chain

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Approve the router (ERC-20)

import { ethers } from "ethers";

// From your previous steps:
const buildTx = /* JSON from /public/emigroswap/buildTransaction */;
const quote   = /* JSON from /public/emigroswap/quote */;

const { routerAddress, amountOut } = buildTx;
const fromTokenAddress = quote.fromTokenAddress;

const erc20 = new ethers.Contract(
  fromTokenAddress,
  ["function approve(address spender, uint256 amount) returns (bool)"],
  wallet
);

// Approve at least the RAW input amount (amountOut)
await erc20.approve(routerAddress, amountOut);

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You can optionally adapt the flow to satisfy conditions in your system, such as creating a swapIntent to save in your database. However, for a clear and error-free execution, simply passing the information received from the quote endpoint to the build calldata already satisfies the requirements to perform the on-chain swap.