US Census ACS 5-year demographics for a state or county. Give a state (2-letter or 2-digit FIPS), optionally a 3-digit county FIPS, and get population, median age, median household income, per-capita income, poverty rate (computed), households, owner-occupancy rate (computed), median home value, and median gross rent. Free, public-domain (US Census Bureau). Complements census.zipcode (ZIP/ZCTA-level) with state- and county-level geography. Authoritative demographic data an LLM cannot recall — for market sizing, site selection, and socioeconomic research.
/api/census/demographicsPAYMENT-SIGNATURE.The demographics API is a pay-per-call census endpoint built for AI agents and autonomous software. US Census ACS 5-year demographics for a state or county.
There is no signup and no API key. An agent (or any HTTP client) hits the endpoint, receives an x402 "402 Payment Required" challenge, signs a sub-cent USDC payment on Base or Solana, and retries — the data comes back on the paid request. That makes it a drop-in demographics data source for an agent tool-use loop, an MCP host, or a backend that needs census data on demand without onboarding to yet another vendor portal.
| Name | Type | Description |
|---|---|---|
staterequired | string | 2-letter state code or 2-digit FIPS. min 2 chars · max 2 chars |
county | string | match ^\d{3}$ |
year | integer | min 2010 · max 2100 |
# 1. Probe with no auth → 402 envelope with PaymentRequirements curl -sS 'https://2s.io/api/census/demographics?state=xx&county=12345&year=2010' # 2. Sign + retry with PAYMENT-SIGNATURE: curl -sS 'https://2s.io/api/census/demographics?state=xx&county=12345&year=2010' \ -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/census/demographics?state=xx&county=12345&year=2010'
import { TwoS } from '@2sio/sdk'
const client = new TwoS({
privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})
const result = await client.census.demographics({
"state": "xx",
"county": "12345",
"year": 2010
})
console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)import os
from twosio import TwoS
client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])
result = client.census.demographics(state="xx", county="12345", year=2010)
print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)// 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": "census.demographics",
"arguments": {
"state": "xx",
"county": "12345",
"year": 2010
}
}
}| Field | Type | Description |
|---|---|---|
ok | boolean | one of: true |
items | array | |
total | integer | Total matching rows upstream; null when unknown. |
source | object |
{
"ok": true,
"items": [
{
"query": {
"state": "example",
"county": "example",
"year": 1
},
"geoName": "example",
"population": 1,
"medianAge": 1,
"medianHouseholdIncomeUSD": 1,
"perCapitaIncomeUSD": 1,
"povertyRate": 1,
"households": 1,
"ownerOccupancyRate": 1,
"medianHomeValueUSD": 1,
"medianGrossRentUSD": 1,
"source": {
"provider": "example",
"url": "example",
"license": "example"
},
"note": "example"
}
],
"total": 1,
"source": {
"provider": "example",
"url": "example",
"license": "example"
}
}