Monitor TRON Blockchain Transactions (HTTP Version Without SDK)

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Monitoring blockchain transactions is a critical requirement for many decentralized applications, especially when managing user deposits and withdrawals. In this guide, we’ll walk through a robust, real-time solution to monitor TRON blockchain transactions—specifically TRX and USDT (TRC20)—without relying on any SDKs. This method uses direct HTTP calls to the TRON network, making it lightweight, efficient, and highly customizable.

Whether you're building a crypto exchange, wallet service, or payment processor, understanding how to track on-chain activity accurately is essential. We'll explore a C# implementation that continuously polls the TRON network, parses transaction data, and identifies relevant transfers to or from monitored addresses.

Why Monitor TRON Blocks Directly?

The TRON blockchain generates a new block approximately every 3 seconds. To ensure no transaction is missed—even during temporary network disruptions—a well-designed monitoring system must:

By using the TRON HTTP API, we eliminate dependencies on third-party SDKs while maintaining full control over performance and reliability.

Core Implementation Overview

The system operates in an infinite loop, fetching the latest block and incrementally checking subsequent ones. It uses two key endpoints from api.trongrid.io:

Here’s how the logic flows:

var blockNumber = 0;
while (true)
{
    var stopWatch = new Stopwatch();
    stopWatch.Start();

    try
    {
        string responseString;
        if (blockNumber == 0)
        {
            // Get the latest block
            const string url = "https://api.trongrid.io/wallet/getnowblock";
            responseString = HttpClientHelper.Get(url);
        }
        else
        {
            // Get next block by number
            const string url = "https://api.trongrid.io/wallet/getblockbynum";
            var requestBody = new { num = blockNumber + 1 };
            responseString = HttpClientHelper.Post(url, JsonConvert.SerializeObject(requestBody), Encoding.UTF8);
        }

        dynamic responseObject = JsonConvert.DeserializeObject(responseString);
        if (responseObject == null || responseObject.blockID == null || responseObject.block_header == null) 
            throw new ThreadSleepException();

        blockNumber = (int)responseObject.block_header.raw_data.number;
        string blockHash = responseObject.blockID;
        long timestamp = responseObject.block_header.raw_data.timestamp;

        Console.WriteLine($"Block Height: {blockNumber}\tHash: {blockHash}");

        // Process transactions
        if (responseObject.transactions != null && responseObject.transactions.Count > 0)
        {
            foreach (var tx in responseObject.transactions)
            {
                // Parse contract type and extract transfer details
                ProcessTransaction(tx);
            }
        }
    }
    catch (ThreadSleepException)
    {
        HandleThrottling(stopWatch);
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Error: {ex.Message}");
        HandleThrottling(stopWatch);
    }

    // Maintain 2.5s polling interval to stay in sync with 3s block time
    if (stopWatch.ElapsedMilliseconds < 2500)
        Thread.Sleep((int)(2500 - stopWatch.ElapsedMilliseconds));
}

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Handling Key Transaction Types

The script identifies three major contract types on the TRON network:

1. TransferContract – Native TRX Transfers

This handles all basic TRX transfers between addresses.

case "TransferContract":
{
    var fromAddress = Base58Encoder.EncodeFromHex(value.owner_address, 0x41);
    var toAddress = Base58Encoder.EncodeFromHex(value.to_address, 0x41);
    decimal amount = (long)value.amount / 1_000_000m; // Convert Sun to TRX

    // Check if either address is being monitored
    if (IsMonitoredAddress(fromAddress) || IsMonitoredAddress(toAddress))
    {
        // Trigger deposit/withdrawal logic
    }
    break;
}

2. TriggerSmartContract – USDT (TRC20) and Other Token Transfers

This captures interactions with smart contracts—primarily USDT (TRC20) transfers.

The contract address used here is:
41a614f803b6fd780986a42c78ec9c7f77e6ded13c (Tether USD)

case "TriggerSmartContract":
{
    if (value.contract_address == "41a614f803b6fd780986a42c78ec9c7f77e6ded13c")
    {
        string data = value.data;
        if (data.StartsWith("a9059cbb")) // Standard ERC20/USDT transfer method ID
        {
            string rawToAddress = data.Substring(8, 64);
            string cleanToHex = rawToAddress.TrimStart('0');
            var toAddressBytes = Enumerable.Range(0, cleanToHex.Length)
                .Where(x => x % 2 == 0)
                .Select(x => Convert.ToByte(cleanToHex.Substring(x, 2), 16))
                .ToArray();

            var toAddress = Base58Encoder.EncodeFromHex("41" + BitConverter.ToString(toAddressBytes).Replace("-", "").ToLower(), 0x41);

            string rawAmount = data.Substring(72, 64);
            long amount = (long)Convert.ToInt64(rawAmount, 16);
            decimal transferAmount = amount / 1_000_000m; // USDT has 6 decimals

            if (IsMonitoredAddress(toAddress))
            {
                // Record incoming USDT deposit
            }
        }
    }
    break;
}

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3. DelegateResourceContract – Resource Delegation Events

Used when energy or bandwidth is delegated. Useful for monitoring staking or resource-sharing activities.

case "DelegateResourceContract":
{
    var receiver = Base58Encoder.EncodeFromHex(value.receiver_address, 0x41);
    // Log or alert if receiver is a monitored address
    break;
}

Performance Optimization with Timing Control

To stay synchronized with the TRON network’s ~3-second block time, the system uses a Stopwatch to enforce a 2.5-second polling interval. This allows the process to:

If processing takes longer than 2.5 seconds, it skips waiting and proceeds immediately—ensuring minimal lag.

Dependency Management

This implementation relies on the following NuGet packages:

Install-Package Newtonsoft.Json
Install-Package StackExchange.Redis
Note: TronNet.Wallet is referenced but not required since we avoid SDK usage.

We use Newtonsoft.Json for parsing API responses and StackExchange.Redis to store and check monitored addresses efficiently.

Redis Integration for Address Monitoring

A simple Redis provider checks whether an address is being tracked:

public class RedisProvider
{
    private readonly IDatabase _database = ConnectionMultiplexer.Connect("127.0.0.1:6379").GetDatabase();
    public static RedisProvider Instance { get; } = new RedisProvider();

    public bool KeyExists(string key) => _database.KeyExists(key);
}

Each transaction’s sender and receiver are checked against Redis-stored addresses. If there's a match, your application can trigger notifications, update balances, or initiate KYC workflows.

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Frequently Asked Questions

Q: Can this method monitor other TRC20 tokens besides USDT?

Yes. Simply replace the contract address in the TriggerSmartContract condition with the token’s TRON address. For example, use TR7NHqjeKQxGTCi8q8ZY4pL8otSzgjLj6t for BTT.

Q: Is polling every 2.5 seconds safe for the API?

Yes. The Trongrid API allows generous rate limits for public use. Using a valid API key (set via TRON-PRO-API-KEY) increases your quota significantly. Consider rotating nodes or using enterprise endpoints for production-scale systems.

Q: What happens if the server restarts? Will I miss transactions?

The current version starts from the latest block each time. For fault tolerance, store the last processed block number in persistent storage (like a database), then resume from that height on restart.

Q: How accurate is USDT transfer parsing?

Very accurate. The a9059cbb method ID is standard across ERC20-compatible tokens. As long as the data format follows ABI encoding (which USDT does), parsing will work reliably.

Q: Can I run this on Linux or only Windows?

Yes, this code runs perfectly on Linux using .NET Core or .NET 6+. Just ensure your runtime environment supports asynchronous HTTP operations and JSON deserialization.

Q: Why not use websockets or event listeners?

While websockets offer push-based updates, they require stable connections and complex reconnection logic. Polling via HTTP is simpler, more reliable for mission-critical apps, and easier to debug.

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With this foundation, you can extend the system to support multi-chain monitoring, database logging, email/SMS alerts, and integration with trading engines or compliance systems.