curl -X POST "https://starknet.api.avnu.fi/staking/v3/pools/0x123abc/members/0x0456def/initiate-withdraw" \
  -H "Content-Type: application/json" \
  -d '{
    "userAddress": "0x0456def...",
    "amount": "0xde0b6b3a7640000"
  }'

async function initiateWithdraw(
  poolAddress: string,
  amount: string,
  account: Account
) {
  const response = await fetch(
    `https://starknet.api.avnu.fi/staking/v3/pools/${poolAddress}/members/${account.address}/initiate-withdraw`,
    {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        userAddress: account.address,
        amount
      })
    }
  );

  const { calls } = await response.json();
  const tx = await account.execute(calls);

  return tx.transaction_hash;
}

{
  "chainId": "0x534e5f4d41494e",
  "calls": [
    {
      "contractAddress": "0x123abc",
      "entrypoint": "initiate_withdraw",
      "calldata": ["0xde0b6b3a7640000", "0"]
    }
  ]
}