Postcodes.io

How to Use This API

1. Single Postcode Lookup

Returns full details for any valid UK postcode:

https://postcodes.io/postcodes/SE14EG

Returns: postcode, longitude, latitude, parliamentary constituency, NHS region, county, district, ward, and more.

2. Bulk Lookup (up to 100)

POST multiple postcodes in one request:

curl -X POST https://postcodes.io/postcodes \
  -H "Content-Type: application/json" \
  -d '{"postcodes": ["SW1A1AA", "EC2N4AY"]}'

3. Random Postcode Generator

Great for testing:

https://postcodes.io/random/postcodes

4. JavaScript — Map a Postcode

async function plotPostcode(postcode) {
  const resp = await fetch(`https://postcodes.io/postcodes/${postcode}`);
  const data = await resp.json();
  const result = data.result;
  
  console.log(`Postcode: ${result.postcode}`);
  console.log(`Location: ${result.latitude}, ${result.longitude}`);
  console.log(`Region: ${result.region}`);
  console.log(`Constituency: ${result.parliamentary_constituency}`);
  
  // Use coordinates with a mapping library
  return { lat: result.latitude, lng: result.longitude };
}

plotPostcode('SE14EG');

5. Python — Validate Postcodes

import requests

postcodes = ['SE14EG', 'SW1A 1AA', 'INVALID']
for pc in postcodes:
    resp = requests.get(f'https://postcodes.io/postcodes/{pc}/validate')
    valid = resp.json()['result']
    print(f"{pc}: {'Valid' if valid else 'Invalid'}")