Chain

Gas / fee oracle API

Current gas conditions for a chain: base fee, suggested priority tip, suggested max fee, and the estimated cost of a standard transfer. Agents call this before sending to set a fee that lands without overpaying.

Price$0.01per request

MethodPOST

Route/v1/chain/gas

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache10s public

chaingasfeeseip1559payments

API URLhttps://x402.hexl.dev/v1/chain/gas

Integration docs

Example request

{
  "chain": "base"
}

Example response

{
  "chain": "base",
  "baseFeeGwei": 0.05,
  "priorityFeeGwei": 0.01,
  "suggestedMaxFeeGwei": 0.11,
  "estTransferCostNative": "0.000002",
  "interpretation": "Base fee ~0.05 gwei. A standard transfer costs about 0.000002 in native token at the suggested max fee.",
  "checkedAt": "2026-06-02T00:00:00.000Z"
}

Input schema

{
  "type": "object",
  "properties": {
    "chain": {
      "type": "string",
      "enum": [
        "base",
        "ethereum"
      ],
      "default": "base"
    }
  }
}

Output schema

{
  "type": "object",
  "required": [
    "chain",
    "baseFeeGwei",
    "suggestedMaxFeeGwei",
    "estTransferCostNative"
  ],
  "properties": {
    "chain": {
      "type": "string"
    },
    "baseFeeGwei": {
      "type": "number"
    },
    "priorityFeeGwei": {
      "type": "number"
    },
    "suggestedMaxFeeGwei": {
      "type": "number"
    },
    "estTransferCostNative": {
      "type": "string"
    },
    "interpretation": {
      "type": "string"
    },
    "checkedAt": {
      "type": "string"
    }
  }
}