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Address capture for developers

UK Address Autocomplete API

Add fast Great Britain address lookup and autofill to checkout, onboarding and CRM forms. Suggestions are free, and you pay only when a user selects an address.

Free type-ahead suggestions35 credits per selected addressMonthly credit plansUPRN includedGreat Britain coverage
Get an API keyView quick start

1 EXAMPLE ROAD

EXAMPLETON, EX1 2AB

10 EXAMPLE ROAD

EXAMPLETON, EX1 2AB

12 EXAMPLE ROAD

EXAMPLETON, EX1 2AB

Fictional addresses shown. Add a manual entry option to every form.

Address lookup API

One search box, two simple API calls

The UK Address Autocomplete API separates fast suggestions from full address retrieval. Call the find endpoint while the user types, then send the selected suggestion ID to retrieve a canonical address, UPRN and coordinates.

1

Search

Send at least three characters, a partial address or a full postcode.

2

Select

Show up to ten suggestions and keep manual address entry available.

3

Retrieve

Retrieve the selected address within 30 minutes. Only this call is charged.

Simple address API pricing

Free suggestions. 35 credits per selected address.

Autocomplete find requests cost 0 credits. A successful retrieve costs 35 API credits. Invalid and expired selections are not charged.

  • ✓ No charge per keystroke
  • ✓ UPRN included
  • ✓ Coordinates included
  • ✓ No separate address subscription
35credits per selected addressView all API plans

Authentication

All requests to the UK Address Autocomplete API require authentication using an API key. You can obtain your API key from your PropertyInsights dashboard after subscribing to an API plan.

Include your API key in the request header as follows: 

X-API-Key: your_api_key_here

Security Warning

Never expose your API key in client-side code. Always make API calls from your server-side application to protect your credentials.

Quick start

1. Find suggestions

curl "https://propertyinsights.co.uk/api/v1/address/autocomplete?query=1%20Example%20Ro&limit=6" \
  -H "x-api-key: YOUR_API_KEY"

2. Retrieve the selection

curl "https://propertyinsights.co.uk/api/v1/address/retrieve?id=SUGGESTION_ID" \
  -H "x-api-key: YOUR_API_KEY"
Keep your API key on your server. Your frontend should call a small endpoint in your own application, which then calls Property Insights.
GET

Find address suggestions

Free
/api/v1/address/autocomplete?query=...&limit=6
ParameterRequiredDescription
queryYes3 to 200 characters. Accepts a partial address or full postcode.
limitNo1 to 10 suggestions. Defaults to 6.
{
  "success": true,
  "data": [
    {
      "id": "v1.eyJ1cHJuIjoiMTAwMDAwMDAwMDAxIn0.signature",
      "text": "1 EXAMPLE ROAD, EXAMPLETON, EX1 2AB",
      "postcode": "EX1 2AB"
    }
  ]
}
GET

Retrieve a selected address

35 API credits
/api/v1/address/retrieve?id=...

Send the signed id returned by the find endpoint. Modified IDs are rejected, and valid IDs expire after 30 minutes.

Billing details in the response

Successful chargeable JSON responses include a top-level billing object. The endpoint examples on this page focus on the endpoint-specific data, so this repeated block may not be shown in every example. 

"billing": {
  "mode": "prepaid",
  "creditsCharged": 1,
  "creditsRemaining": 1999,
  "creditsRefreshAt": "2026-08-14T09:30:00.000Z"
}
Field or headerMeaning
billing.creditsCharged
X-Credits-Charged		Credits charged by this call. Failed and non-chargeable calls return 0 in the header.
billing.creditsRemaining
X-Credits-Remaining		The credit balance after the call.
billing.creditsRefreshAt
X-Credits-Refresh-At		The next monthly credit refresh as an ISO 8601 timestamp. Trial and non-renewing balances return null and omit the header.

All authenticated API-key calls expose the billing headers, including validation errors and zero-credit status or management requests. Only successful chargeable JSON responses add the billing object to the response body.

Selected address response

The canonical single-line value is returned alongside practical form fields. All example details are fictional.

{
  "success": true,
  "data": {
    "address": "FLAT 1, EXAMPLE HOUSE, EXAMPLE ROAD, EXAMPLETON, EX1 2AB",
    "addressLines": ["FLAT 1", "EXAMPLE HOUSE", "EXAMPLE ROAD"],
    "line1": "FLAT 1",
    "line2": "EXAMPLE HOUSE",
    "line3": "EXAMPLE ROAD",
    "town": "EXAMPLETON",
    "postcode": "EX1 2AB",
    "country": "GB",
    "uprn": "100000000001",
    "latitude": 51.5001,
    "longitude": -0.1001
  }
}

Coverage and data notes

The API currently covers postcode-bearing Ordnance Survey AddressBase Core records in England, Scotland and Wales.

It identifies an addressable property and its UPRN. It does not currently certify Royal Mail deliverability, include PAF Multiple Residence records or cover Northern Ireland.

Always provide manual address entry when an address is missing or newly created.

Address autocomplete API questions

What does an address lookup cost?

Type-ahead suggestions are free. Retrieving a selected address costs 35 API credits.

Does the API return a UPRN?

Yes. A successful retrieve response includes the UPRN, canonical single-line address, practical form fields, postcode and coordinates.

Is this a Royal Mail PAF address validation API?

No. The current API uses postcode-bearing Ordnance Survey AddressBase Core records for Great Britain. It should not be used as proof that Royal Mail can deliver to an address.

Can I call the API directly from a browser?

Keep your Property Insights API key on your server. Call the API through a small backend route in your application so the key is not exposed to visitors.

How long does a suggestion ID remain valid?

A signed suggestion ID remains valid for 30 minutes. Run a new find request if the user returns to the form later.