UK grounding service · built for AI agents

Give postcode answers a place to stand.

Validate a UK postcode and return its retained ONS geography fields through a straightforward JSON API or, in supporting browsers, a WebMCP tool.

Try a lookup View API example About postcode validation API specification

A small, explicit contractJSON

{
  "service": "uk-postcode-grounding",
  "status": "found",
  "normalizedPostcode": "SW1A1AA",
  "data": {
    "postcode": "SW1A 1AA",
    "latitude": 51.501009,
    "longitude": -0.141588,
    "country_code": "E92000001",
            "region_code": "E12000007"
  }
}

Illustrative response shape. The API includes the stored normalized and raw ONS fields.

Try a postcode

This form and the agent tool use the same public lookup service.

Plain JSON API

No API key. Send a postcode to a versioned endpoint and receive the source fields as typed JSON.

WebMCP tool

A read-only browser tool is registered where WebMCP is available. The API works independently of browser support.

Source and limits

Based on ONSPD February 2025. BT postcodes are withheld pending confirmation of Northern Ireland licensing.