GET
$0.0011 default
/v1/evm/gasDescription
Multi-chain EVM gas price oracle for AI agents — 17 chains (Ethereum, Base, Arbitrum, Optimism, Polygon, BNB, Avalanche…). One x402 call returns slow/standard/fast EIP-1559 tiers as DROP-IN maxFeePerGas + maxPriorityFeePerGas in wei (plug straight into a viem/ethers tx, no conversion, exact even on sub-gwei L2s), plus base fee, head block, and fullness, from a live eth_feeHistory call. Pass ?chain= to switch chains.
Pricing
$0.0011 default
Parameters
{
"properties": {
"blocks": {
"description": "Recent blocks to sample for percentile reward (1..50, clamped).",
"maximum": 50,
"minimum": 1,
"type": "integer"
},
"chain": {
"description": "Target EVM chain id. One of: ethereum, base, optimism, arbitrum, polygon, avalanche, gnosis, linea, scroll, blast, mode, opbnb, celo, bsc, fantom, zksync, mantle. Also accepts common aliases (eth, arb, op, matic, avax, bnb). Default: ethereum.",
"enum": [
"ethereum",
"base",
"optimism",
"arbitrum",
"polygon",
"avalanche",
"gnosis",
"linea",
"scroll",
"blast",
"mode",
"opbnb",
"celo",
"bsc",
"fantom",
"zksync",
"mantle"
],
"type": "string"
}
},
"required": [
"chain"
],
"type": "object"
}Example response
{
"base_fee_gwei": 8.421,
"base_fee_wei": "8421000000",
"block_number": 21403217,
"caip2": "eip155:1",
"chain": "ethereum",
"chain_name": "Ethereum mainnet",
"gas_model": "eip1559",
"stats": {
"blocks_sampled": 20,
"median_fullness_pct": 45.5,
"ts": "2026-05-28T15:42:30.000Z"
},
"tiers": {
"fast": {
"maxFeePerGas": "14831000000",
"maxPriorityFeePerGas": "2200000000",
"max_fee_gwei": 14.831,
"max_priority_gwei": 2.2
},
"slow": {
"maxFeePerGas": "12631000000",
"maxPriorityFeePerGas": "1000000",
"max_fee_gwei": 12.631,
"max_priority_gwei": 0.001
},
"standard": {
"maxFeePerGas": "13731000000",
"maxPriorityFeePerGas": "1100000000",
"max_fee_gwei": 13.731,
"max_priority_gwei": 1.1
}
}
}