Getting approval without the Pay component

To set or change the approval amount, you can construct the transaction yourself for the payer to set their authorization. This approval is required before a payment can take place.

Set/change the authorization

You can call the approve function to set the authorization. This function must be signed by the wallet that is paying.

Input	Description	Where to find
Token contract	This is the address of the ERC-20 token contract.	Chain ids & token addresses
Spender	This is the address of your Loop smart contract. There is a different address per blockchain.	Response to the Get Entity call.

EVM (e.g. Ethereum, Polygon, Base, Optimism, etc)

function approve(address spender, uint256 amount) external returns (bool);

Solana

On Solana, the equivalent of the approve function in Ethereum is done via the approve instruction in the SPL Token Program. You authorize an account (the spender) to transfer a certain amount of tokens from your token account. The spender address must be your specific Loop contract address for the network

const {
  Connection,
  PublicKey,
  Keypair,
  Transaction,
  sendAndConfirmTransaction,
} = require('@solana/web3.js');

const { Token, TOKEN_PROGRAM_ID } = require('@solana/spl-token');

async function increaseTokenApproval() {
  // Set up your connection to Solana's mainnet
  const connection = new Connection('https://api.mainnet-beta.solana.com', 'confirmed');

  // Your wallet's keypair (Replace with your actual keypair)
  const wallet = Keypair.fromSecretKey(new Uint8Array([/* your private key array */]));

  // Token mint address for the SPL Token (replace with the token you want to use)
  const tokenMintAddress = new PublicKey('YourTokenMintAddressHere');

  // The token account where the tokens are stored
  const fromTokenAccount = new PublicKey('YourTokenAccountAddressHere');

  // Spender account (the account you're authorizing to spend tokens)
  const spenderAddress = new PublicKey('SpenderAccountAddressHere');

  // New approval amount (in token's smallest unit, e.g., 1000 tokens for a token with 9 decimals)
  const amountToApprove = 1000 * Math.pow(10, 9);  // For tokens with 9 decimals

  // Create the Token object for the mint address
  const token = new Token(connection, tokenMintAddress, TOKEN_PROGRAM_ID, wallet);

  // Create the approve instruction
  const approveIx = Token.createApproveInstruction(
    TOKEN_PROGRAM_ID, // SPL Token Program
    fromTokenAccount, // Source token account
    spenderAddress,   // Spender account
    wallet.publicKey, // Owner of the token account
    [],               // Multisig signers (if any)
    amountToApprove   // Amount to approve
  );

  // Create the transaction
  const transaction = new Transaction().add(approveIx);

  // Send the transaction
  try {
    const signature = await sendAndConfirmTransaction(connection, transaction, [wallet]);
    console.log('Transaction confirmed with signature:', signature);
  } catch (error) {
    console.error('Error sending transaction:', error);
  }
}

increaseTokenApproval();