Multi-chain gas oracle with USD cost API

Current gas price across N EVM chains (ethereum, base, arbitrum, optimism, polygon, bsc, avalanche) in ONE call, each joined with its native-token USD price to quote the concrete dollar cost of a plain transfer and a typical swap, ranked cheapest-first. Saves agents from per-chain RPC + price calls and error-prone wei->gwei->USD math. Answers 'gas price on base vs arbitrum', 'cheapest chain to transact right now', 'how much USD to send a transaction', 'multi-chain gas comparison'.

Price$0.01per request

MethodPOST

Route/v1/chain/gas-multi

StatusLive

MIME typeapplication/json

Rate limit60/minute

Cache3600s public

chaingasfeesmulti-chaingweirpcevmcost

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

Integration docs

Example request

{
  "chains": [
    "ethereum",
    "base"
  ]
}

Example response

{
  "count": 2,
  "cheapest": "base",
  "chains": [
    {
      "chain": "base",
      "native": "ETH",
      "gasPriceGwei": 0.006,
      "nativeUsd": 1830.3,
      "transferCostNative": 1.3e-7,
      "transferCostUsd": 0.0002,
      "swapCostNative": 9e-7,
      "swapCostUsd": 0.0016
    }
  ],
  "checkedAt": "2026-06-03T18:56:32.800Z"
}

Input schema

{
  "type": "object",
  "required": [],
  "properties": {
    "chains": {
      "type": "array",
      "items": {
        "type": "string"
      },
      "examples": [
        [
          "ethereum",
          "base",
          "arbitrum"
        ]
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}