Privacy Policy: Kerbio

Last updated 10 September 2026. This policy covers only the Chrome extension named Kerbio.

What the extension does

When you open a property listing on rightmove.co.uk, zoopla.co.uk or onthemarket.com, the extension reads the listing's location (postcode and map coordinates) from the page you are viewing and shows Article 4 status, HMO licensing rules, licensed HMOs nearby, and a sold-price comparison for that council. On the search results pages of those same three sites, it adds a small status badge to each result card (Article 4, licensed HMOs nearby, price vs sold comparison, and whether you've already saved that listing) using the same page data, read locally in your browser. It does nothing on any other website.

Data the extension sends, and to whom

• The listing's postcode and coordinates are sent to two public data services to answer your query: api.postcodes.io (to identify the council) and www.planning.data.gov.uk (the UK Government planning data service, to check Article 4 directions). No account, name, email or browsing history is sent with them.
• Payment status is handled by ExtensionPay (extensionpay.com), which processes subscriptions through Stripe. If you start a trial or subscribe, ExtensionPay holds your email address and payment status. The extension only asks ExtensionPay whether your installation is paid or in trial. We never see your card details.

Data the extension stores

All stored locally in your browser (chrome.storage.local), never sent to us:

• A cached copy of your last known trial or subscription status, so a temporary outage of the payment service does not lock you out.
• Pipeline. If you press "Save to pipeline", the extension stores a snapshot of that listing (address, postcode, price, the panel's results, and the listing photo shown on the page) plus notes and a stage you set, so you can track it. This never leaves your browser unless you use the CSV export, which downloads a file to your own computer.
• Owner letters. If you use the letter feature (see below), your own name, postal address and contact details (so they can be printed on your letters), your edited letter text, and a suppression list of addresses you have marked as opted out are kept locally. Never sent anywhere.

Owner letters

The extension can prepare a print-ready letter addressed to "The Owner" at a property address: the listing you are viewing, or licensed HMOs near it drawn from the council registers already bundled with the extension or downloaded from our own site (see below). The letters contain no names and no data from the register beyond the property address; the recipient is always "The Owner". Nothing is fetched or sent to produce them, and the extension does not post or send anything on your behalf: you print and send the letters yourself and you are responsible for them, including honouring any request not to be contacted again (the built-in suppression list is there for that).

Data we do not collect

No browsing history, no analytics, no tracking, no advertising, no sale or sharing of data. The extension does not send us the listings you look at, your searches, or anything you save to your pipeline. Everything above stays in your own browser.

Permissions, and why

• storage: to cache your payment status locally.
• Access to listing and search-results pages on rightmove.co.uk, zoopla.co.uk and onthemarket.com: to read the listing location and draw the panel, or the small status badges on results pages. On a Rightmove results page the extension also reads each listed property's own page (same site, in the background) for its description and tenure, so the keyword and motivated-seller filter can work without you opening every listing. Those reads are cached on your device for a day. The prices you see on listings are remembered on your device so that a later price drop can be pointed out. They are also sent to our site as anonymous price observations (the portal's listing number, the price, the date it was seen and the date the portal says it was listed; nothing about you, no account, no identifier) and merged with every other user's observations into a shared price history that all users see. You can turn this sharing off in the extension's popup at any time. Saved searches are stored on your device, and saved Rightmove searches are re-run by the extension once a day in the background so it can count new or reduced listings on its toolbar badge. None of this is sent to us or anyone else.
• Access to api.postcodes.io, www.planning.data.gov.uk and extensionpay.com: the three services described above.
• Access to spareroom.co.uk and Zoopla's rental search: only when you press "Check rents and demand", the extension fetches SpareRoom's public search results and Zoopla's public rental results for the listing's postcode district to count rooms wanted and rooms listed and read the advertised rents. Nothing is fetched automatically and nothing about you is sent.
• Access to deluxe-cascaron-2fd7ae.netlify.app: our own site, from which the extension downloads its reference data (Article 4 lists, licensing tables, council registers) so it can be kept current without an extension update. Nothing about you is sent there; the request is a plain file download.

Accuracy

Article 4 results come from data councils publish to the national planning data service, which is incomplete. Where a council has published nothing, the extension says so rather than showing "no". Sold-price comparisons come from HM Land Registry Price Paid Data, a public dataset with no bedroom counts, so they compare by street, distance and house type, not size. Always confirm with the council before making an offer.

Contact

Luke Rallings, enquiries@swiftresolve.co.uk