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Overview

Tron deposits require building a TRC-20 token transfer transaction using TronWeb, then appending the call_data as hex-encoded data before signing and broadcasting. Prerequisites:
  • tronweb for transaction building and RPC communication
Supported networks: Tron Mainnet, Tron Testnet (Shasta/Nile)

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call_data Format

For Tron, call_data is a plain string (a memo identifier). It is converted to hex and embedded in the transaction data field: 
const hexData = Buffer.from(callData).toString("hex");
This hex data is appended to the transaction using TronWeb’s addUpdateData method, which Layerswap uses to identify and match the deposit.

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Full Example (Server-side)

import { TronWeb } from "tronweb";

async function executeTronDeposit(
  depositAction: any,
  senderAddress: string,
  privateKey: string
) {
  const { call_data, to_address, amount, token, network } = depositAction;

  const tronWeb = new TronWeb({
    fullNode: network.node_url,
    solidityNode: network.node_url,
    privateKey,
  });

  const amountInBaseUnits = Math.floor(
    amount * Math.pow(10, token.decimals)
  );

  // Build the TRC-20 transfer via smart contract
  const { transaction: initialTransaction } =
    await tronWeb.transactionBuilder.triggerSmartContract(
      token.contract,
      "transfer(address,uint256)",
      {
        feeLimit: 100_000_000, // 100 TRX fee limit
      },
      [
        { type: "address", value: to_address },
        { type: "uint256", value: amountInBaseUnits },
      ],
      senderAddress
    );

  // Append call_data as hex data
  const hexData = Buffer.from(call_data).toString("hex");
  const transaction = await tronWeb.transactionBuilder.addUpdateData(
    initialTransaction,
    hexData,
    "hex"
  );

  // Sign and broadcast
  const signedTransaction = await tronWeb.trx.sign(transaction);
  const result = await tronWeb.trx.sendRawTransaction(signedTransaction);

  if (result.result) {
    return signedTransaction.txID;
  }

  throw new Error("Transaction broadcast failed");
}

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Browser Wallet Example

When using a Tron wallet adapter (TronLink, etc.) in the browser: 
import { TronWeb } from "tronweb";

async function executeTronDeposit(
  depositAction: any,
  senderAddress: string,
  signTransaction: (tx: any) => Promise<any>
) {
  const { call_data, to_address, amount, token, network } = depositAction;

  const tronWeb = new TronWeb({
    fullNode: network.node_url,
    solidityNode: network.node_url,
  });

  const amountInBaseUnits = Math.floor(
    amount * Math.pow(10, token.decimals)
  );

  const { transaction: initialTransaction } =
    await tronWeb.transactionBuilder.triggerSmartContract(
      token.contract,
      "transfer(address,uint256)",
      { feeLimit: 100_000_000 },
      [
        { type: "address", value: to_address },
        { type: "uint256", value: amountInBaseUnits },
      ],
      senderAddress
    );

  const hexData = Buffer.from(call_data).toString("hex");
  const transaction = await tronWeb.transactionBuilder.addUpdateData(
    initialTransaction,
    hexData,
    "hex"
  );

  // Sign using the wallet adapter
  const signedTransaction = await signTransaction(transaction);
  const result = await tronWeb.trx.sendRawTransaction(signedTransaction);

  if (result.result) {
    return signedTransaction.txID;
  }

  throw new Error("Transaction broadcast failed");
}

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Next Step

After the transaction is submitted, notify Layerswap so it can match your deposit faster: 
curl -X POST https://api.layerswap.io/api/v2/swaps/{swap_id}/deposit_speedup \
  -H "X-LS-APIKEY: your_api_key" \
  -H "Content-Type: application/json" \
  -d '{ "transaction_id": "YOUR_TX_HASH" }'
See the full deposit flow for details.