Gas Statistics

The gasStats topic streams per-shard gas price and PPU (Price Per Unit) statistics every 50ms. Use this data to set competitive gas prices, detect shard congestion, and time transaction submission.

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Subscribe

ws.send(JSON.stringify({
  action: 'subscribe',
  topic: 'gasStats'
}));

An initial snapshot is delivered immediately upon subscription. Updates follow every 50ms while the subscription is active.

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Message Schema

Each message covers a single shard. A separate message is emitted per shard per interval.

{
  "type": "gasStats",
  "data": {
    "shard": 0,
    "gasPrice": {
      "min": 1000000000,
      "max": 1500000000,
      "avg": 1200000000,
      "bucketAvg": 1210000000,
      "percentiles": {
        "p50": 1150000000,
        "p75": 1350000000,
        "p90": 1450000000
      }
    },
    "ppu": {
      "min": 10,
      "max": 15,
      "avg": 12,
      "bucketAvg": 12.1
    }
  }
}

Field Descriptions

Field	Type	Description
type	string	Always "gasStats"
data.shard	number	Shard identifier: 0, 1, or 2
data.gasPrice.min	number	Minimum gas price observed in the current window (atomic units)
data.gasPrice.max	number	Maximum gas price observed in the current window (atomic units)
data.gasPrice.avg	number	Simple average gas price across the full 30-minute window (atomic units)
data.gasPrice.bucketAvg	number	Weighted average computed from 10-second buckets — less sensitive to old data
data.gasPrice.percentiles.p50	number	50th percentile gas price; half of transactions paid at or below this value
data.gasPrice.percentiles.p75	number	75th percentile gas price
data.gasPrice.percentiles.p90	number	90th percentile gas price; spam-resistant upper bound for competitive pricing
data.ppu.min	number	Minimum Price Per Unit in the window
data.ppu.max	number	Maximum Price Per Unit in the window
data.ppu.avg	number	Average Price Per Unit across the full window
data.ppu.bucketAvg	number	Bucket-weighted average PPU

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Sliding Window and Bucket Algorithm

Gas statistics are computed over a 30-minute sliding window divided into 10-second buckets (180 buckets total).

• As each bucket expires, it is dropped from the window and the oldest transaction data is discarded.

• The avg fields represent a simple mean across all transactions in the full 30-minute window.

• The bucketAvg fields are computed as the mean of per-bucket averages, giving more recent buckets equal weight regardless of transaction volume. This prevents a high-volume period from distorting the metric.

• Percentiles (p50, p75, p90) are computed over the sliding window using reservoir sampling. Because spam transactions cluster at the minimum gas price, percentiles above p50 provide a spam-resistant view of what legitimate transactions actually paid.

Choosing a Gas Price

Goal	Recommended value
Minimum acceptance	1000000000 (network minimum)
Fast inclusion, low congestion	gasPrice.bucketAvg
Reliable inclusion	gasPrice.percentiles.p75
Priority inclusion under congestion	gasPrice.percentiles.p90

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PPU — Price Per Unit

PPU is the effective cost per unit of gas computation, factoring in the transaction's data payload. For a plain EGLD transfer with no data, PPU equals gasPrice. For transactions with a data field, each byte costs an additional 1,500 gas units at the current gas price, making PPU higher than the raw gasPrice.

Use PPU to compare the true cost of transactions with different data sizes.

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Example: Dynamic Gas Price Selection

class GasAdvisor {
  constructor() {
    this.stats = new Map(); // shard -> latest gasStats data

    this.ws = new WebSocket('wss://relayer.xoxno.com/ws');

    this.ws.onopen = () => {
      this.ws.send(JSON.stringify({ action: 'subscribe', topic: 'gasStats' }));
    };

    this.ws.onmessage = (event) => {
      const msg = JSON.parse(event.data);
      if (msg.type === 'gasStats') {
        this.stats.set(msg.data.shard, msg.data);
      }
    };
  }

  /**
   * Returns a gas price for the given shard suitable for reliable inclusion.
   * Falls back to the network minimum if no data is available.
   */
  getGasPrice(shard, priority = 'normal') {
    const data = this.stats.get(shard);
    if (!data) return 1000000000;

    switch (priority) {
      case 'low':    return data.gasPrice.bucketAvg;
      case 'normal': return data.gasPrice.percentiles.p75;
      case 'high':   return data.gasPrice.percentiles.p90;
      default:       return data.gasPrice.percentiles.p75;
    }
  }

  /**
   * Returns true if the given shard's avg gas price is significantly
   * above the network minimum, indicating congestion.
   */
  isCongested(shard) {
    const data = this.stats.get(shard);
    if (!data) return false;
    return data.gasPrice.avg > 1200000000;
  }
}

const advisor = new GasAdvisor();

// After connection stabilizes, use advisor:
// const gasPrice = advisor.getGasPrice(0, 'normal');

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Unsubscribe

ws.send(JSON.stringify({
  action: 'unsubscribe',
  topic: 'gasStats'
}));

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Use Cases

• Dynamic fee estimation — Set gasPrice on outbound transactions using percentiles.p75 for reliable confirmation without overpaying.

• Congestion detection — Monitor avg across shards; route time-sensitive operations away from congested shards when possible.

• Wallet fee display — Show users a real-time estimated fee before they confirm a transaction.

• MEV / sequencing tools — Use bucketAvg and percentiles to model current mempool competition.

When a shard has no recent transactions, all gas price fields return 1000000000 (the network minimum) and PPU fields return 0. This indicates the shard has full capacity available.

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Related Pages

• Network Statistics — TPS, mempool pressure, block times

• Transaction Broadcasting — Submit pre-signed transactions

• Transaction Relaying — Co-signed relayed transactions

• Error Reference — WebSocket error codes