Property ID Changes and Redirects

HelloData maintains a consistent property identifier (id) for each building to allow users to retrieve full property details and history. However, in rare but important edge cases, these IDs can change.

The /property/search endpoint is always free—feel free to use it when something looks off.

When Do Property IDs Change?

We may update the property ID you receive in the following scenarios:

1. Property Merges

When two properties (say A and B) are merged into one new property C:

  • Both A and B will redirect to C.
  • Your old id will still work and return property C.

2. Property Splits

When a property is split into multiple distinct properties:

  • The old ID (e.g. A) will redirect to one of the resulting new properties (e.g. B or C).
  • We recommend re-checking the address or building_name if you’re unsure.

3. Major Address or Identity Changes

If a property’s ZIP code, city, or address is significantly updated:

  • We may assign a new ID to the updated property.
  • The old ID will redirect to the new one.

If your request to /property/{id} returns a 404, it may be due to one of these transitions. Use /property/search to find the updated ID.

Tips for Developers

  • Use Search as Backup: If an ID returns unexpected results, confirm via the /property/search endpoint using name or address.
  • Alias Matching: The building_name_alias and street_address_alias fields can help confirm that you’re looking at the right property.
  • Cache Sensibly: Property IDs are generally stable, but if you rely on them long term, consider periodic revalidation.

Example

You originally fetched:

1GET /property/11111-11111-11111-11111
2{
3  "id": "22222-22222-22222-22222",
4  "building_name": "Main Street Apartments",
5  "building_name_alias": ["Main Apartments"],
6  "street_address": "1234 New Ave"
7}

This is expected behavior—you’re still seeing the correct property under the latest data we have. We redirect to the new ID to ensure you always get the most up-to-date information.