Skip to main content
Sure can look up a property’s estimated market value when you add a property account and refresh that estimate automatically on a recurring schedule. Three providers are supported: RentCast and Realie for US properties, and Chimnie for UK residential properties.

How it works

When you add a new property account using a valuation provider:
  1. You enter the property name and address
  2. Sure sends the address (or UPRN for Chimnie) to the provider
  3. The provider returns the property record and an estimated value
  4. You review the result before anything is created
  5. Confirming creates the property account with the estimated value as the opening balance
After setup, Sure queues automatic valuation refreshes on the first of each month. Each property keeps its selected provider. RentCast and Realie also require at least a day between automatic refreshes; Chimnie requires a month. Properties are processed stalest-first, subject to provider configuration, address and currency checks, and the remaining monthly request budget.

Enabling a provider

Add the API key for the provider you want to use. You can do this in two ways:
  • Settings UI — go to Settings → Self-Hosting and enter the key in the provider’s field
  • Environment variable — set RENTCAST_API_KEY, REALIE_API_KEY, or CHIMNIE_API_KEY in your environment
Once a key is present, the provider appears as an option when you add a new property account.

Providers

RentCast

RentCast is a US property data API. The free tier allows 50 requests per month.

Realie

Realie is a US property data and AVM API. The free tier allows 25 requests per month.

Realie API versions (v2 and v3)

Realie introduced a v3 response shape on 2026-08-19. The response shape is an account-level setting that all API keys on the account inherit:
  • v2 flat record — the original shape, still active for accounts created before the v3 release unless you opt in.
  • v3 nested parcel record — the default for accounts created after 2026-08-19. Older accounts can switch to v3 from the Realie dashboard. The switch is one-way.
Sure handles both shapes automatically. No configuration change is needed when your Realie account is on v3 or when you opt in later.

Chimnie

Chimnie is a UK property valuation API. UPRN-based valuations are free and include an estimated value, value range, and confidence level. Sure caps requests at 1,000 per month by default.
Create an account and API key at dashboard.chimnie.com. Check Chimnie’s current sign-up requirements if registration is rejected.
Chimnie looks up properties by their UPRN (Unique Property Reference Number), not by address. You need the UPRN when adding a property through Chimnie. Finding your UPRN: every UK address has a UPRN of up to 12 digits. You can find it at findmyaddress.co.uk (GeoPlace) or by asking your local council. Chimnie includes attribution in the property preview: valuation data from Chimnie contains OS data © Crown copyright and database right, Royal Mail data © Royal Mail copyright and database right, and HM Land Registry data © Crown copyright and database right, licensed under the Open Government Licence v3.0.

Monthly request budget

Each provider tracks requests in a durable database counter that resets at the start of each calendar month. This counter covers both user-initiated lookups (adding a property) and automatic refreshes. The refresh job checks the counter before spending a request and stops when the budget is exhausted. For Chimnie, Sure retries HTTP 429 responses with exponential backoff, for up to three retries. Each provider instance spaces requests at least 1.1 seconds apart. Every attempt counts against the monthly cap, and requests stop when that cap is reached. The free tier caps are conservative. If you have a paid plan with a higher limit, set the override variable to match:

Linking a valuation provider to an existing property

If you added a property manually (without using a valuation provider at creation time), you can link a provider later from the property’s Overview tab. A property is eligible to link when all of these are true:
  • No provider is already linked
  • The property has a complete address in the provider’s supported country. For RentCast and Realie, provide a US street address, city, state, ZIP code, and country
  • The property’s account currency matches the provider’s valuation currency (USD for RentCast and Realie; GBP for Chimnie)
  • The provider does not require an external identifier (Chimnie requires a UPRN, so it can only be linked at creation time, not after)
  • The provider’s API key is configured
When you click the link button, Sure runs the first valuation immediately. The link is kept only if that valuation succeeds. If the address is not found or the monthly budget is exhausted, the link is reverted and the property stays unlinked so you can try a different provider. To link a provider:
  1. Open the property account and go to the Overview tab
  2. If the property is eligible, an Update value automatically with [provider name] button appears for each configured, eligible provider. You need write access to link it
  3. Click the button for the provider you want to use
  4. Sure runs the first valuation and confirms whether the link succeeded
After linking, the Overview tab shows the last valuation date and a Refresh valuation button. The property is included in future automatic monthly refreshes.

Adding a property using a valuation provider

US properties (RentCast or Realie)

  1. Go to Accounts → Add Account → Property
  2. Select Add via RentCast or Add via Realie (these options appear only when the provider’s API key is configured)
  3. Enter the property name and its full US address
  4. Click Look up property
  5. Review what the provider found — the property type, estimated value, and other details are shown before anything is saved. If the address matched an area estimate rather than a specific record, a notice says so
  6. Click Add property to confirm, or Back to correct the address

UK properties (Chimnie)

  1. Go to Accounts → Add Account → Property
  2. Select Add via Chimnie (this option appears only when the CHIMNIE_API_KEY is configured)
  3. Enter the property name, its UK address (address line 1 and postcode are required; county is optional), and its UPRN
  4. Click Look up property
  5. Review what Chimnie found — the estimated value, value range, and confidence level are shown before anything is saved
  6. Click Add property to confirm, or Back to correct the details
Nothing is created until you confirm. If the lookup fails (UPRN not found, rate limit reached, provider error), an error message explains the reason.

Automatic refresh

The default background job runs monthly, on the first day of the month at 01:30 in the scheduler’s configured timezone. It considers active property accounts with a linked valuation provider. A provider’s minimum interval also applies: one day for RentCast and Realie, and one month for Chimnie. Properties are processed in order of their last refresh date, oldest first. A property is skipped if:
  • It was already refreshed within the provider’s refresh interval
  • Its address fields required by the provider are missing
  • The provider only supports a specific country and the property’s address does not match
  • Its currency does not match the provider’s valuation currency
  • The provider’s monthly request budget is exhausted
  • The provider’s API key has been removed since the property was added
Address, provider-configuration, and currency failures are recorded in Settings → Debug logs under the provider key. Routine interval and exhausted-budget skips may not create a log entry. A Refresh valuation button on the property account bypasses the normal interval and queues a fresh valuation, still subject to the provider budget and validation checks. The button is disabled if the provider is no longer configured.

Troubleshooting

The valuation option is not showing when I add a property: the provider’s API key is not configured. Add the relevant key (RENTCAST_API_KEY, REALIE_API_KEY, or CHIMNIE_API_KEY) to your environment, or enter it in Settings → Self-Hosting. Chimnie sign-up was rejected: check Chimnie’s current registration requirements or contact its support team. The UPRN lookup returned no result: the UPRN may be for a non-residential property, a newly built property not yet in Chimnie’s database, or an invalid number. Double-check the UPRN on findmyaddress.co.uk. The provider returned an area estimate instead of a property record: the address was not matched to a specific record. The confirmation screen says so explicitly. Review the address for typos before confirming — if the address is correct but the provider has no record for it, you can still add the property and manage its value manually. The value stopped updating: the provider’s monthly budget is likely exhausted. Check Settings → Debug logs filtered to the provider key, or check your provider dashboard. The budget resets at the start of the next calendar month, or you can raise the cap with the override variable if you are on a paid plan. The property account’s currency does not match the provider: RentCast and Realie return values in USD; Chimnie returns values in GBP. If your property account was created or later changed to a different currency, the refresh job skips it to avoid writing the wrong currency. Change the account currency to match or manage the value manually. No link button appears on the Overview tab for an existing property: check that the provider’s API key is configured, the address includes every required field and a supported country, and the account currency matches the provider’s valuation currency. Chimnie cannot be linked after creation because it requires a UPRN that can only be supplied when the property is first added. The link failed with an alert: the first valuation did not succeed, so the link was not saved. The address may not be in the provider’s database or the monthly budget may be exhausted. Correct the address or wait for the budget to reset, then try again.