Your session
Does closing the browser tab end my session?
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 uk-property-paid.entzai.com
and navigate to
/app — your session will still be active.
What if I close the entire browser?
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.
What if I clear my cookies or browse in private/incognito mode?
If you clear your browser cookies, the session token is lost and you will
be locked out of the remaining queries. There is currently no way to
recover a session after cookies are cleared. Keep this in mind before
clearing your browser data. Private/incognito windows do not share cookies
with your main browser profile, so a session started in regular mode will
not work in incognito.
Can I use OpenProp on multiple devices?
Not yet — sessions are tied to the browser where you paid. Using a different
device means a different cookie store, so you would not have access there.
We are considering adding email-based login to solve this —
vote for it here.
Queries & usage
What counts as one query?
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.
Do I get a chart with every answer?
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.
What is a planning evidence report?
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.
What happens when I hit 10 queries?
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.
The data
What data does OpenProp use?
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.
How up to date is the data?
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.
What areas are covered?
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.
How can I verify the figures myself?
Our full calculation notebook is published on Kaggle —
the same scripts that generate the data behind this tool.
View the open validation notebook →
Payments & refunds
Why can't I get a refund?
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.
What does £1.99 + VAT mean?
The base price is £1.99 excluding VAT. UK VAT at 20% is added automatically
by Stripe at checkout, bringing the total to £2.39 inc. VAT.
Both figures are shown clearly before you pay.
Is Stripe safe?
Yes. Payment is processed entirely by
Stripe,
a PCI-DSS Level 1 certified payment processor.
OpenProp never sees or stores your card details.
What happens after 7 days?
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.
Technical
Which browsers are supported?
Any modern browser — Chrome, Firefox, Safari, Edge. Cookies must be
enabled (required for session management). Very old browsers (pre-2020)
may have display issues.
Does it work on mobile?
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.
Why is it slow sometimes?
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.