MEV & Trading APIs

Axol provides specialized APIs for MEV (Maximal Extractable Value) extraction, trading automation, and DeFi opportunity detection. These endpoints are designed for low-latency, high-reliability applications like trading bots, liquidation bots, and arbitrage systems.

Feature Overview

Feature	Description	Use Case
Gas Oracle	Multi-provider gas prices with failover	Transaction timing optimization
Mempool Streaming	Real-time pending transaction monitoring	Arbitrage detection, sandwich protection
DeFi Liquidations	Position health and opportunity detection	Liquidation bots
Gateway	Direct node access for low latency	Latency-critical operations
MEV Bundles	Flashbots bundle submission	Atomic transaction execution

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Quick Start

1. Get Gas Prices (No Auth Required)

curl https://api.axol.io/api/v1/oracle/gas/ethereum

Response:

{
  "chain": "ethereum",
  "slow": {"max_fee_gwei": 25.0, "priority_fee_gwei": 1.0},
  "standard": {"max_fee_gwei": 27.0, "priority_fee_gwei": 2.0},
  "fast": {"max_fee_gwei": 30.0, "priority_fee_gwei": 3.0},
  "instant": {"max_fee_gwei": 35.0, "priority_fee_gwei": 5.0},
  "base_fee_gwei": 24.0,
  "network_congestion": "medium",
  "stale": false
}

2. Stream Mempool Transactions

Python:

import asyncio
import websockets
import json

async def monitor():
    uri = "wss://api.axol.io/api/v1/mempool/ethereum/stream"
    headers = {"X-API-Key": "YOUR_KEY"}

    async with websockets.connect(uri, extra_headers=headers) as ws:
        await ws.send(json.dumps({
            "action": "subscribe",
            "filter": {"tx_types": ["swap"], "min_value_eth": 1.0}
        }))

        async for msg in ws:
            print(json.loads(msg))

asyncio.run(monitor())

3. Find Liquidation Opportunities

curl -H "X-API-Key: YOUR_KEY" \
  "https://api.axol.io/api/v1/defi/ethereum/liquidations/opportunities?min_profit_usd=100"

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Supported Chains

Gas Oracle

Ethereum, Polygon, Arbitrum, Optimism, Base, Avalanche

Mempool Monitoring

Ethereum, Gnosis, Optimism, Arbitrum

DeFi Liquidations

Ethereum, Optimism, Arbitrum, Polygon, Base, Gnosis

Gateway (Direct Node Access)

Ethereum, Optimism, Base, Arbitrum

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Key Concepts

Multi-Provider Failover

All Oracle endpoints use multiple RPC providers with automatic failover:

1. Primary provider is tried first
2. If it fails, backup providers are queried in parallel
3. If all providers fail, cached data is served (marked stale: true)

This ensures your bot never goes blind, even during RPC outages.

Cache TTLs

Data Type	Cache TTL	Update Frequency
Gas	3s	Every 3 seconds
Lrt	30s	Every 30 seconds
Beacon	12s	Every 12 seconds
L1 Data Fee	12s	Every 12 seconds
Prices	60s	Every 60 seconds
Blocks	3s	Every 3 seconds

Transaction Classification

Mempool transactions are automatically classified:

Type	Description
swap	DEX trades (Uniswap, SushiSwap, etc.)
liquidation	Lending protocol liquidations
transfer	Simple token transfers
flashloan	Flash loan operations
bridge	Cross-chain bridge transactions
nft	NFT trades and mints
other	Unclassified transactions

MEV Opportunity Detection

Detected opportunities include:

Type	Description
arbitrage	Price discrepancy across DEXes
sandwich	Sandwich opportunity around large swaps
liquidation	Profitable liquidation opportunity
backrun	Backrun opportunity after large trade
frontrun	Frontrun opportunity (detected for awareness)

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Best Practices

1. Use WebSocket for Real-Time Data

For time-sensitive operations, always prefer WebSocket over polling:

# Good - WebSocket streaming
async with websockets.connect(uri) as ws:
    async for msg in ws:
        process(msg)

# Bad - Polling REST endpoint
while True:
    response = requests.get(url)
    process(response)
    time.sleep(0.1)  # Wastes time and rate limits

2. Handle Stale Data Gracefully

When providers fail, you'll receive cached data marked as stale:

gas = response.json()
if gas['stale']:
    # Data is cached, may be outdated
    # Consider adding safety margin or skipping trade
    gas_price = gas['fast']['max_fee_gwei'] * 1.2  # 20% buffer
else:
    gas_price = gas['fast']['max_fee_gwei']

3. Filter Aggressively

Reduce noise by filtering to only relevant transactions:

await ws.send(json.dumps({
    "action": "subscribe",
    "filter": {
        "tx_types": ["swap"],
        "min_value_eth": 10.0,
        "dex_protocols": ["uniswap_v3"],
        "include_mev": True
    }
}))

4. Monitor Provider Health

Check oracle health before critical operations:

health = requests.get(f"{BASE_URL}/oracle/health").json()
if health['overall_status'] != 'healthy':
    # Consider fallback strategy
    logger.warning(f"Oracle degraded: {health}")

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Rate Limits

MEV endpoints have higher rate limits to support trading applications:

Tier	Oracle (req/min)	Mempool WS	DeFi (req/min)
Free	300	1 connection	60
Pro	3000	5 connections	600
Enterprise	Unlimited	20 connections	Unlimited

Oracle endpoints (/oracle/*) do not require authentication and have generous limits.

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Next Steps

• Gas Oracle API - Detailed oracle documentation
• Mempool Streaming - Transaction monitoring
• DeFi Liquidations - Liquidation detection
• Building a Trading Bot - Complete tutorial