Frequently Asked Questions

No. Your session is stored as a persistent cookie with a 7-day expiry. Closing the tab, minimising the browser, or even restarting your computer will not end it. Simply return to app.openprop.co.uk and navigate to /app — your session will still be active.

Same answer — closing the browser does not clear persistent cookies. Your session will be waiting when you reopen the browser, as long as the 7-day window hasn't expired.

If you clear your browser cookies, the session cookie is removed from that browser — but your session is not lost. Visit app.openprop.co.uk/recover and enter the email address you used when you paid via Stripe. We'll restore your remaining queries on the new browser or device. Private/incognito windows do not share cookies with your main browser profile, so use the recovery page to regain access there too.

Yes — use the session recovery page. Go to app.openprop.co.uk/recover on the new device and enter the email address from your Stripe receipt. Your remaining queries will be restored on that device. Note that using multiple devices simultaneously shares the same query pool — queries are not doubled.

Absolutely. The underlying HM Land Registry data is publicly available and we've published Kaggle notebooks so you can query the full 5 GB database yourself — no payment needed beyond a free Kaggle account.

Open validation notebook (methodology) →

Query the 5 GB database yourself →

Important: before you start, read How OpenProp Works . Data filtration is critical — querying the raw CSV without the correct filters produces different medians and counts from what our tool shows. The article explains exactly which filters to apply.

Each message you send in the chat counts as one query. The counter increments the moment you submit your question, regardless of whether a chart is generated. Follow-up messages in the same conversation each count separately.

Most analytical questions (price trends, borough comparisons, volume over time) produce a chart automatically. Simple factual answers (e.g. "what is the median price in Wandsworth?") may return text only. You can toggle chart generation on or off using the checkbox in the app.

OpenProp can generate a structured planning market evidence note — useful for S106 pre-negotiation, housing needs assessments, and viability appraisals. Ask something like "Generate a planning evidence note for SW11" and the app will produce a downloadable .docx report. This counts as one query.

The app will show a message explaining the session is complete and provide a link back to the landing page to purchase a new session. Any remaining time within the 7-day window is forfeited once the query limit is reached.

All transaction data comes from HM Land Registry Price Paid Data (Crown copyright, Open Government Licence v3.0). This is the official record of every residential property sold in England and Wales and submitted for registration.

The dataset covers 2010 to the most recent monthly update. HM Land Registry typically publishes updates with a 2–3 month lag as solicitors complete registration. Our pipeline refreshes monthly via Kaggle.

Greater London only — all 33 boroughs. Coverage includes postcode-level analysis for postcode districts (e.g. SW18, E1) and full boroughs (e.g. Wandsworth, Hackney). Individual street or flat-level lookup is not yet available.

Our full calculation notebook is published on Kaggle — the same scripts that generate the data behind this tool. View the open validation notebook →

Under UK Consumer Contracts Regulations 2013, you waived your 14-day cooling-off right when you ticked the consent checkbox and confirmed immediate access. This is standard practice for instant-access digital services. Refunds remain available if the service is faulty or materially different from what was described.

No. The price is £1.99 in total — no VAT is added at checkout. VAT will be introduced in a future update when applicable.

Yes. Payment is processed entirely by Stripe, a PCI-DSS Level 1 certified payment processor. OpenProp never sees or stores your card details.

Your session expires and you will be redirected to the landing page. Any unused queries within the 7-day window are forfeited — sessions do not roll over or extend automatically.

Any modern browser — Chrome, Firefox, Safari, Edge. Cookies must be enabled (required for session management). Very old browsers (pre-2020) may have display issues.

Yes, the landing page and FAQ are fully responsive. The chat interface works on mobile but is best experienced on a desktop or tablet where the chart and conversation panels are visible side by side.

The AI analysis backend is hosted on a shared server that enters a low-power state after periods of inactivity. The first query of a session may take 30–60 seconds while the backend wakes up. Subsequent queries are faster (typically 5–15 seconds). A "waking up" message will appear if this happens.