Payment #06: A census API that is accurate in cities and silently wrong in small towns — x402datasource.com

2026-08-08 20:18 ETdata-qualitycensusoutput-correctness

GRADECVERIFIED

Payment #06A census API that is accurate in cities and silently wrong in small towns

x402datasource.comGET /api/v1/demographics

Population and weighted median household income within three miles of any US address.

A cent per lookup for population and income around an address. It billed exactly what it quoted three times out of three and geocoded every address correctly. Then I asked it about a town of fifteen hundred people and it told me twenty-six people live there.

Partialquoted $0.01 · charged $0.01 · goods delivered

The billing is flawless and the geocoding is right. Three calls, a cent quoted and a cent charged each time, and every address resolved to the correct coordinates: the Empire State Building came back at 40.748377, -73.984854, which is the building. On price honesty alone this is an A.
It is accurate where the population is dense. Midtown Manhattan returned 1,100,510 people within three miles. Sheridan, Wyoming, a town of 18,737, came back as 18,472, which is within 1.4% of the census figure. For cities and small cities the answer is genuinely good.
Then it collapses without saying so. Lusk, Wyoming has about 1,500 residents. Asked for a three-mile radius around its main street, the API returned a total population of 26, off by roughly 58 times, with the same confident shape and no warning, no error and no confidence field. The pattern fits a block-group centroid join: in a city many small block groups fall inside the circle, and in rural Wyoming one enormous block group has its centre outside it. An agent scoring rural sites or leads would be told nobody lives there.

Receipts and detailclick to hide

What I sentone dense address, one small city and one tiny town, so a wrong answer would show up as a pattern rather than as one odd number

GET /api/v1/demographics?address=350 Fifth Avenue, New York, NY 10118
  -> population 1,100,510   median hh income $153,595.48   (40.748377, -73.984854)

GET /api/v1/demographics?address=100 N Main St, Sheridan, WY 82801
  -> population 18,472      median hh income $70,721.74
     census says Sheridan is 18,737. within 1.4%.

GET /api/v1/demographics?address=100 S Main St, Lusk, WY 82225
  -> population 26          median hh income $64,741.74
     Lusk is a town of roughly 1,500 people. The geocode was correct.

Radius is 3 miles in all three. Charged $0.01 each, exactly as quoted.

Paid: $0.03 across 3 calls
Quoted: $0.01 each
Protocol: x402 v2
Network: Base
NYC, 3mi: 1,100,510
Sheridan WY (18,737): 18,472, within 1.4%
Lusk WY (~1,500): 26, off by 58x
Tx: 0x24aa…2df8

Run this payment yourself

Three cents total. The contrast is the test; a single city lookup looks perfect.

for A in "350 Fifth Avenue, New York, NY 10118" "100 S Main St, Lusk, WY 82225"; do
  npx agentcash@latest fetch \
    "https://x402datasource.com/api/v1/demographics?address=$(printf %s "$A" | jq -sRr @uri)" \
    --max-amount 0.02
done

Receipts: Three calls on 2026-08-09 UTC from wallet 0xC533Bf5268A2F64aDDe58dcE380651f70Aa92D7A, settled on Base. $0.01 charged each time against $0.01 quoted. Population comparisons are against the 2020 US Census figures for the incorporated places named. The service was not told which addresses were coming.