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eth_gasPrice

Returns the current gas price in wei. This represents the median gas price from recent blocks on IoTeX L1.

When to Use This Method​

eth_gasPrice is essential for:

  • Transaction Pricing - Set appropriate gas prices for transactions
  • Fee Estimation - Calculate transaction costs for users
  • Gas Strategy - Optimize transaction speed vs cost
  • Market Monitoring - Track network congestion levels

Parameters​

None - This method takes no parameters.

{
  "jsonrpc": "2.0",
  "method": "eth_gasPrice",
  "params": [],
  "id": 1
}

Returns​

QUANTITY - Current gas price in wei (hexadecimal).

Implementation Examples​

import { JsonRpcProvider, formatGwei, formatEther } from 'ethers';

const provider = new JsonRpcProvider('https://api-iotex-mainnet.n.dwellir.com/YOUR_API_KEY');

// Gas price monitoring and optimization
class GasPriceManager {
  constructor(provider) {
    this.provider = provider;
    this.priceHistory = [];
    this.updateInterval = null;
  }

  async getCurrentGasPrice() {
    const gasPrice = await this.provider.getGasPrice();
    
    return {
      wei: gasPrice.toString(),
      gwei: formatGwei(gasPrice),
      eth: formatEther(gasPrice),
      hex: gasPrice.toHexString(),
      timestamp: Date.now()
    };
  }

  async getGasPriceWithContext() {
    // Get multiple data points for context
    const [gasPrice, feeData, block] = await Promise.all([
      this.provider.getGasPrice(),
      this.provider.getFeeData(),
      this.provider.getBlock('latest')
    ]);

    // Calculate percentiles for better pricing
    const baseFee = block.baseFeePerGas || 0n;
    const priorityFee = feeData.maxPriorityFeePerGas || 0n;
    
    return {
      current: {
        gasPrice: formatGwei(gasPrice),
        unit: 'gwei'
      },
      eip1559: {
        baseFee: formatGwei(baseFee),
        priorityFee: formatGwei(priorityFee),
        maxFeePerGas: formatGwei(feeData.maxFeePerGas),
        recommended: formatGwei(baseFee + priorityFee)
      },
      speeds: {
        slow: formatGwei(gasPrice * 90n / 100n),
        standard: formatGwei(gasPrice),
        fast: formatGwei(gasPrice * 120n / 100n),
        instant: formatGwei(gasPrice * 150n / 100n)
      },
      networkCongestion: this.assessCongestion(baseFee)
    };
  }

  assessCongestion(baseFee) {
    const baseGwei = Number(formatGwei(baseFee));
    
    if (baseGwei < 0.1) return 'very low';
    if (baseGwei < 0.5) return 'low';
    if (baseGwei < 1) return 'moderate';
    if (baseGwei < 5) return 'high';
    return 'very high';
  }

  async calculateTransactionCost(gasLimit, gasPriceMultiplier = 1) {
    const gasPrice = await this.provider.getGasPrice();
    const adjustedPrice = gasPrice * BigInt(Math.floor(gasPriceMultiplier * 100)) / 100n;
    const cost = adjustedPrice * BigInt(gasLimit);
    
    return {
      gasLimit: gasLimit.toString(),
      gasPrice: formatGwei(adjustedPrice),
      totalCostWei: cost.toString(),
      totalCostGwei: formatGwei(cost),
      totalCostETH: formatEther(cost),
      dollarValue: await this.estimateUSDValue(cost)
    };
  }

  async estimateUSDValue(costWei) {
    // This would typically fetch ETH price from an oracle
    // For demonstration, using a static value
    const ethPrice = 3000; // USD
    const costETH = Number(formatEther(costWei));
    return (costETH * ethPrice).toFixed(4);
  }

  startMonitoring(intervalMs = 5000, callback) {
    this.stopMonitoring();
    
    this.updateInterval = setInterval(async () => {
      const price = await this.getCurrentGasPrice();
      this.priceHistory.push(price);
      
      // Keep only last 100 entries
      if (this.priceHistory.length > 100) {
        this.priceHistory.shift();
      }
      
      if (callback) {
        callback(price, this.getStatistics());
      }
    }, intervalMs);
  }

  stopMonitoring() {
    if (this.updateInterval) {
      clearInterval(this.updateInterval);
      this.updateInterval = null;
    }
  }

  getStatistics() {
    if (this.priceHistory.length === 0) return null;
    
    const prices = this.priceHistory.map(p => BigInt(p.wei));
    const sum = prices.reduce((a, b) => a + b, 0n);
    const avg = sum / BigInt(prices.length);
    const min = prices.reduce((a, b) => a < b ? a : b);
    const max = prices.reduce((a, b) => a > b ? a : b);
    
    return {
      samples: prices.length,
      average: formatGwei(avg),
      minimum: formatGwei(min),
      maximum: formatGwei(max),
      current: formatGwei(prices[prices.length - 1]),
      trend: this.calculateTrend()
    };
  }

  calculateTrend() {
    if (this.priceHistory.length < 2) return 'stable';
    
    const recent = this.priceHistory.slice(-10);
    const older = this.priceHistory.slice(-20, -10);
    
    if (older.length === 0) return 'stable';
    
    const recentAvg = recent.reduce((sum, p) => sum + BigInt(p.wei), 0n) / BigInt(recent.length);
    const olderAvg = older.reduce((sum, p) => sum + BigInt(p.wei), 0n) / BigInt(older.length);
    
    const change = Number(recentAvg - olderAvg) / Number(olderAvg) * 100;
    
    if (change > 10) return 'increasing';
    if (change < -10) return 'decreasing';
    return 'stable';
  }

  async waitForLowerGas(targetGwei, timeoutMs = 60000) {
    const startTime = Date.now();
    
    while (Date.now() - startTime < timeoutMs) {
      const current = await this.getCurrentGasPrice();
      
      if (parseFloat(current.gwei) <= targetGwei) {
        return {
          success: true,
          gasPrice: current,
          waitTime: Date.now() - startTime
        };
      }
      
      await new Promise(resolve => setTimeout(resolve, 2000));
    }
    
    return {
      success: false,
      reason: 'timeout',
      currentPrice: await this.getCurrentGasPrice()
    };
  }
}

// Usage examples
const gasPriceManager = new GasPriceManager(provider);

// Get current gas price
const currentPrice = await gasPriceManager.getCurrentGasPrice();
console.log(`Current gas price: ${currentPrice.gwei} gwei`);

// Get comprehensive gas data
const gasData = await gasPriceManager.getGasPriceWithContext();
console.log('Network congestion:', gasData.networkCongestion);
console.log('Recommended speeds:', gasData.speeds);

// Calculate transaction cost
const txCost = await gasPriceManager.calculateTransactionCost(21000); // ETH transfer
console.log(`Transaction cost: ${txCost.totalCostETH} ETH (~$${txCost.dollarValue})`);

// Monitor gas prices
gasPriceManager.startMonitoring(5000, (price, stats) => {
  console.log(`Gas: ${price.gwei} gwei | Trend: ${stats?.trend}`);
});

// Wait for lower gas
const result = await gasPriceManager.waitForLowerGas(0.5, 30000);
if (result.success) {
  console.log('Gas price dropped to target!');
}

Common Use Cases​

1. Dynamic Fee Adjustment​

// Dynamically adjust fees based on network conditions
async function getOptimalGasPrice(urgency = 'standard') {
  const gasPrice = await provider.getGasPrice();
  const block = await provider.getBlock('latest');
  const baseFee = block.baseFeePerGas;
  
  const multipliers = {
    low: 0.9,
    standard: 1.0,
    high: 1.2,
    urgent: 1.5
  };
  
  const multiplier = multipliers[urgency] || 1.0;
  const adjustedPrice = gasPrice * BigInt(Math.floor(multiplier * 100)) / 100n;
  
  // For EIP-1559 transactions
  const maxPriorityFee = adjustedPrice - baseFee;
  const maxFeePerGas = baseFee * 2n + maxPriorityFee;
  
  return {
    legacy: {
      gasPrice: adjustedPrice,
      formatted: formatGwei(adjustedPrice) + ' gwei'
    },
    eip1559: {
      maxFeePerGas: maxFeePerGas,
      maxPriorityFeePerGas: maxPriorityFee,
      formatted: {
        maxFee: formatGwei(maxFeePerGas) + ' gwei',
        priorityFee: formatGwei(maxPriorityFee) + ' gwei'
      }
    },
    estimatedConfirmationBlocks: urgency === 'urgent' ? 1 : urgency === 'high' ? 2 : 3
  };
}

2. Gas Price Oracle​

// Create a gas price oracle with caching
class GasPriceOracle {
  constructor(provider, cacheTime = 5000) {
    this.provider = provider;
    this.cacheTime = cacheTime;
    this.cache = null;
    this.lastFetch = 0;
  }
  
  async getPrice() {
    const now = Date.now();
    
    if (this.cache && (now - this.lastFetch) < this.cacheTime) {
      return this.cache;
    }
    
    const gasPrice = await this.provider.getGasPrice();
    
    this.cache = {
      wei: gasPrice,
      gwei: formatGwei(gasPrice),
      timestamp: now
    };
    this.lastFetch = now;
    
    return this.cache;
  }
  
  async getPriceWithRecommendations() {
    const price = await this.getPrice();
    const gweiPrice = parseFloat(price.gwei);
    
    return {
      ...price,
      recommendations: {
        sendNow: gweiPrice < 1,
        waitSuggested: gweiPrice > 5,
        congestionLevel: gweiPrice < 0.5 ? 'low' : gweiPrice < 2 ? 'normal' : 'high'
      }
    };
  }
}

3. Transaction Cost Calculator​

// Calculate and display transaction costs
async function calculateDetailedCosts(gasLimit) {
  const gasPrice = await provider.getGasPrice();
  const ethPrice = 3000; // Would fetch from price feed
  
  const costs = {
    slow: gasPrice * 90n / 100n,
    standard: gasPrice,
    fast: gasPrice * 120n / 100n
  };
  
  const results = {};
  
  for (const [speed, price] of Object.entries(costs)) {
    const totalWei = price * BigInt(gasLimit);
    const totalETH = Number(formatEther(totalWei));
    
    results[speed] = {
      gasPrice: formatGwei(price) + ' gwei',
      totalETH: totalETH.toFixed(6) + ' ETH',
      totalUSD: '$' + (totalETH * ethPrice).toFixed(2),
      percentOfTransfer: gasLimit === 21000 ? 'N/A' : 
        ((Number(totalWei) / Number(parseEther('1'))) * 100).toFixed(3) + '%'
    };
  }
  
  return results;
}

Error Handling​

Error ScenarioDescriptionSolution
Network timeoutRPC connection issuesRetry with exponential backoff
Invalid responseMalformed data from nodeValidate response format
Stale dataCached price too oldForce refresh
async function getRobustGasPrice(maxRetries = 3) {
  let lastError;
  
  for (let i = 0; i < maxRetries; i++) {
    try {
      const gasPrice = await provider.getGasPrice();
      
      // Validate response
      if (!gasPrice || gasPrice === 0n) {
        throw new Error('Invalid gas price returned');
      }
      
      // Sanity check - IoTeX L1 shouldn't have extremely high gas
      const gweiPrice = Number(formatGwei(gasPrice));
      if (gweiPrice > 1000) {
        console.warn('Unusually high gas price detected:', gweiPrice);
      }
      
      return gasPrice;
      
    } catch (error) {
      lastError = error;
      
      // Exponential backoff
      if (i < maxRetries - 1) {
        await new Promise(resolve => 
          setTimeout(resolve, Math.pow(2, i) * 1000)
        );
      }
    }
  }
  
  throw new Error(`Failed to get gas price after ${maxRetries} attempts: ${lastError.message}`);
}

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