vehicle.fuel-economy

Official US EPA/DOE fuel-economy, fuel-cost, and emissions data for a vehicle by year + make + model. Because a model-year often has several powertrain configurations (engine/transmission), this returns one entry per configuration, each with: MPG city/highway/combined (or MPGe for EVs), CO2 tailpipe grams/mile, estimated annual fuel cost (USD), annual petroleum use (barrels), EPA greenhouse-gas score (1-10), 5-year savings vs the average new vehicle, plus transmission, drivetrain, cylinders, displacement, fuel type, EPA size class, and electric range for EV/PHEV. Authoritative EPA test figures — the real ratings an agent should not estimate. Keyless, public-domain (FuelEconomy.gov), covers model years 1984+.

price

$0.0018 USDC per call

method

GET/api/vehicle/fuel-economy

payment

x402 v2 · USDC on Base (EIP-3009) or Solana (SPL transfer)

auth

None. Sign the payment, retry with PAYMENT-SIGNATURE.

tier

Tier 0 — no paid upstream

Parameters

Name	Type	Description
`year`required	integer	min 1984 · max 2100
`make`required	string	min 1 chars · max 40 chars
`model`required	string	min 1 chars · max 60 chars

Code samples

cURLbash

# 1. Probe with no auth → 402 envelope with PaymentRequirements
curl -sS 'https://2s.io/api/vehicle/fuel-economy?year=1984&make=example&model=example'

# 2. Sign + retry with PAYMENT-SIGNATURE:
curl -sS 'https://2s.io/api/vehicle/fuel-economy?year=1984&make=example&model=example' \
  -H 'PAYMENT-SIGNATURE: <base64-json-payload>'

# Or use the canonical runner (handles probe → sign → retry):
#   EVM_PRIVATE_KEY=0x... node --env-file=.env.local \
#     --experimental-strip-types scripts/x402-pay.ts \
#     'https://2s.io/api/vehicle/fuel-economy?year=1984&make=example&model=example'

TypeScript / Node — @2sio/sdktypescript

import { TwoS } from '@2sio/sdk'

const client = new TwoS({
  privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})

const result = await client.vehicle.fuelEconomy({
  "year": 1984,
  "make": "example",
  "model": "example"
})

console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)

Python — 2siopython

import os
from twosio import TwoS

client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])

result = client.vehicle.fuel_economy(year=1984, make="example", model="example")

print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)

MCP — Claude Desktop / AgentKit / any MCP hostjson

// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
//    EVM_PRIVATE_KEY funds x402 payments per call.

// claude_desktop_config.json
{
  "mcpServers": {
    "2sio": {
      "command": "npx",
      "args": ["-y", "@2sio/mcp"],
      "env": { "EVM_PRIVATE_KEY": "0x..." }
    }
  }
}

// 2. Once the server is running, agents call this tool via standard MCP:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "vehicle.fuel-economy",
    "arguments": {
      "year": 1984,
      "make": "example",
      "model": "example"
    }
  }
}

Response

Field	Type	Description
`ok`	boolean	one of: true
`items`	array
`total`	integer	Total matching rows upstream; null when unknown.
`source`	object
`meta`	object

Example response datajson

{
  "ok": true,
  "items": [
    {
      "id": "example",
      "description": "example",
      "year": 1,
      "make": "example",
      "model": "example",
      "vehicleClass": "example",
      "transmission": "example",
      "drive": "example",
      "cylinders": 1,
      "displacementL": 1,
      "fuelType": "example",
      "mpgCity": 1,
      "mpgHighway": 1,
      "mpgCombined": 1,
      "co2GramsPerMile": 1,
      "annualFuelCostUSD": 1,
      "annualPetroleumBarrels": 1,
      "ghgScore": 1,
      "fiveYearSavingsVsAvgUSD": 1,
      "electricRangeMi": 1
    }
  ],
  "total": 1,
  "source": {
    "provider": "example",
    "url": "example",
    "license": "example"
  },
  "meta": {
    "query": {
      "year": 1,
      "make": "example",
      "model": "example"
    },
    "total": 1
  }
}

Discovery

/api/directory — full catalog of every endpoint
/openapi.json — OpenAPI 3.1 spec (per-op x-payment-info, x402Payment security)
/.well-known/x402 — machine-readable service descriptor for x402-aware crawlers
/.well-known/mcp/server-card.json — MCP SEP-1649 server card
/llms.txt — plain-text manifest for LLM ingestion

2s.io is x402-native. Every call is paid per-request from a USDC-funded EVM wallet on Base — no signup, no API keys, no monthly fees. Source code: github.com/2s-io/sdk.