Gas-price forecast (next ~hour) API

Read eth_feeHistory from a free public RPC, compute an EWMA + linear trend slope of the base fee, project it ~1 hour out, and layer recent priority-fee tips to produce slow/standard/fast estimates in gwei. The value-add is the forecast. Differs from chain-gas (current spot) and chain-gas-history (past percentiles). Answers 'will gas be cheaper in an hour', 'predicted gas price', 'forecast slow vs fast gas', 'is base fee trending up'.

Price$0.01per request

MethodPOST

Route/v1/chain/gas-forecast

StatusLive

MIME typeapplication/json

Rate limit60/minute

Cache3600s public

chaingasforecastewmabasefeeethereumbasepredict

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

Integration docs

Example request

{
  "chain": "base",
  "blocks": 60
}

Example response

{
  "chain": "base",
  "horizonBlocks": 1800,
  "currentBaseFeeGwei": 15,
  "forecastBaseFeeGwei": 17.4,
  "trendSlopeGweiPerBlock": 0.05,
  "direction": "rising",
  "priorityTipGwei": 1.5,
  "forecast": {
    "slowGwei": 18.15,
    "standardGwei": 18.9,
    "fastGwei": 21.39
  }
}

Input schema

{
  "type": "object",
  "properties": {
    "chain": {
      "type": "string",
      "enum": [
        "base",
        "ethereum"
      ],
      "default": "base"
    },
    "blocks": {
      "type": "number",
      "default": 60,
      "minimum": 5,
      "maximum": 256
    }
  }
}

Output schema

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