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SiteCheck Postcode Lookup
x402
SiteCheck Postcode Lookup is a paid API for AI agents from api.sitecheck-api.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-23).
Resolves a postcode or ZIP code to geographic and administrative details including coordinates, region, district, and constituency
Price / call$0.001
Success—
StatusUnknown
How this service works
Place names and coordinates for a postcode. GB adds district, ward and constituency (postcodes.io); other countries use Zippopotam.us for ZIP and postal codes. A postcode that does not exist answers 404, not charged.
Output
A JSON object containing the postcode, an array of matching places each with latitude, longitude, county, region, district, place name, and constituency, plus the country code, lookup timestamp, data source attribution, and a link to postcodes.io.
Example use cases
Address verification for e-commerce checkout
“Can you check whether the postcode W1A 0AX is valid for the UK and tell me what district and region it belongs to so I can validate the shipping address?”
Constituency lookup for political research
“I need to know which parliamentary constituency the postcode EC1A 1BB falls in — can you look that up for me?”
Geocoding postcodes for mapping application
“I have a UK postcode, SW1H 0ET — can you get me the latitude and longitude for it so I can plot it on a map?”
Technical details
Endpoint
GEThttps://api.sitecheck-api.workers.dev/api/postcode?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to resolve a UK postcode (or other country ZIP code) to structured geographic and administrative data including coordinates, region, district, and constituency. It is backed by postcodes.io with OS Crown copyright data, making it authoritative for UK addresses. Prefer it over generic geocoding APIs when administrative boundary data (constituency, district, county) is needed alongside coordinates.
Side effects
- Invalid or malformed postcode returns an error or empty places array
- Unsupported country code may yield no results
- Postcode that no longer exists (retired postcodes) may return empty results
- Missing required query parameters (country or code) returns a validation error
- Network timeout or upstream postcodes.io unavailability
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"code": "SW1A 1AA",
"places": [
{
"lat": 51.50101,
"lon": -0.141563,
"county": null,
"region": "London",
"district": "Westminster",
"placeName": "St James's",
"constituency": "Cities of London and Westminster"
}
],
"source": "postcodes.io (https://api.postcodes.io)",
"country": "GB",
"checkedAt": "2026-10-14T04:49:24.511Z",
"attribution": "Contains OS data © Crown copyright and database right; postcodes.io (Open Government Licence v3.0)"
}
}Tags
x402
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