Fee Estimation

using System.Numerics;
using Nethereum.Hex.HexTypes;
using Nethereum.RPC.Eth.DTOs;
using Nethereum.RPC.Fee1559Suggestions;

var fee = new Fee1559
{
    BaseFee = 20_000_000_000,
    MaxPriorityFeePerGas = 2_000_000_000,
    MaxFeePerGas = 42_000_000_000
};

var defaultPriority = SimpleFeeSuggestionStrategy.DEFAULT_MAX_PRIORITY_FEE_PER_GAS;
// 2,000,000,000 (2 Gwei)

// Usage with Web3:
// var strategy = new SimpleFeeSuggestionStrategy(web3.Client);
// Fee1559 fee = await strategy.SuggestFeeAsync();

var strategy = new MedianPriorityFeeHistorySuggestionStrategy();

strategy.GetBaseFeeMultiplier(30_000_000_000);   // 2.0x  (< 40 Gwei)
strategy.GetBaseFeeMultiplier(50_000_000_000);   // 1.6x  (40-100 Gwei)
strategy.GetBaseFeeMultiplier(150_000_000_000);  // 1.4x  (100-200 Gwei)
strategy.GetBaseFeeMultiplier(300_000_000_000);  // 1.2x  (>= 200 Gwei)

var feeHistory = new FeeHistoryResult
{
    OldestBlock = new HexBigInteger(100),
    BaseFeePerGas = new[]
    {
        new HexBigInteger(20_000_000_000),
        new HexBigInteger(21_000_000_000)
    },
    GasUsedRatio = new decimal[] { 0.5m },
    Reward = new[]
    {
        new[] { new HexBigInteger(1_000_000_000) },
        new[] { new HexBigInteger(1_500_000_000) },
        new[] { new HexBigInteger(2_000_000_000) },
        new[] { new HexBigInteger(2_500_000_000) },
        new[] { new HexBigInteger(3_000_000_000) }
    }
};

var estimate = strategy.EstimatePriorityFee(feeHistory);

var maxPriorityFee = new BigInteger(2_000_000_000);
var baseFee = new HexBigInteger(30_000_000_000);

Fee1559 result = strategy.SuggestMaxFeeUsingMultiplier(maxPriorityFee, baseFee);
// result.MaxFeePerGas > baseFee (includes multiplier headroom)
// result.MaxPriorityFeePerGas == maxPriorityFee

var strategy = new TimePreferenceFeeSuggestionStrategy();

// Build fee history (normally from eth_feeHistory RPC)
var feeHistory = new FeeHistoryResult
{
    OldestBlock = new HexBigInteger(1000),
    BaseFeePerGas = baseFees,   // HexBigInteger[101]
    GasUsedRatio = gasUsedRatio // decimal[100]
};

var tip = new BigInteger(2_000_000_000);
Fee1559[] fees = strategy.SuggestFees(feeHistory, tip);

foreach (var fee in fees)
{
    // fee.MaxFeePerGas >= fee.MaxPriorityFeePerGas
}

web3.TransactionManager.Fee1559SuggestionStrategy =
    new SimpleFeeSuggestionStrategy(web3.Client);

web3.TransactionManager.UseLegacyAsDefault = true;
// Or provide GasPrice in TransactionInput — legacy is used automatically

// Simple
var simple = new SimpleFeeSuggestionStrategy(web3.Client);
Fee1559 fee = await simple.SuggestFeeAsync();

// Median
var median = new MedianPriorityFeeHistorySuggestionStrategy(web3.Client);
Fee1559 fee = await median.SuggestFeeAsync();

// TimePreference
var timePref = new TimePreferenceFeeSuggestionStrategy(web3.Client);
Fee1559[] fees = await timePref.SuggestFeesAsync();