Privacy policy

Effective September 9, 2026. Last updated October 25, 2026. Version 4.6. Version 3 names the search-result and map data that sharing sends, the scoring records we keep, our backup provider, and how deletion works. If you turned sharing on under version 2, the extension asks you again.

Lowball is a free Chrome extension that estimates fair rent for Zillow rental listings and suggests an offer. It is run by its founder, an individual operator in the United States. This policy covers the extension, our server at api.lowball.rent, and this website. It explains exactly what leaves your browser, when, and why.

The short version: we work with listing facts, not with you. The extension has no accounts, no names, and no emails; the one place this website asks for an email is the optional renting-or-buying form, described in its own section below. Two things we do handle are worth knowing about: a random install identifier, attached to what you send only while sharing is on, and your IP address, which reaches our server with every request as it does for any website.

What the extension reads

Lowball runs only on pages at zillow.com. It watches the listing data Zillow loads into the page and picks out rental listings. From a listing it reads: price, base rent, bedrooms, bathrooms, square footage, year built, home type, street address, city, ZIP code, map coordinates, days on Zillow, price history, Zillow's published rent estimate, posted specials, lease length, whether the owner listed it, the listing description text, and, for buildings, the list of available units.

It does not read other websites, your Zillow account, your saved homes, your search terms or filters, or anything you type on Zillow. When Zillow opens a listing in place and has not loaded its data yet, the extension may re-read the page that is open in your tab, one request, using your normal browser session, only to read that listing. That is the only request the extension ever makes to Zillow. It does not crawl, follow links, or fetch pages you did not open. It never loads any other page on its own.

Sent to our server to score a listing

To produce an estimate, the extension sends the listing facts above, except the description text and Zillow's rent estimate, which stay in your browser, to our server at api.lowball.rent over HTTPS and gets an estimate back. The description is checked in your browser for words like "short-term" or "furnished" and only those two yes-or-no answers are sent. On search result pages it sends the facts for each listing card on screen so it can add a badge to each one. When you open a listing or an apartment building, the request also carries up to 40 of the listings from the search results and maps your browser has already loaded, in any tab, that sit within five miles of it (listing id, street address or building name, coordinates, asking rent, last price change, beds, baths, square footage, home type, days listed, and a building's starting rents). The extension holds those listings in the browser's session memory, which is cleared when the browser closes. A building's request carries the building's coordinates, taken from its search card or its page. Where we have no local data, those are the comparable rentals the estimate is built from. They are used for that one answer and are not kept. The extension never requests extra pages from Zillow to collect them. These requests carry no identifier for you and no account. We do not store them. Like every web server, ours sees your IP address when it answers; see "Server logs" below.

Kept from scoring requests

For every estimate we keep one listing-level scoring record for 12 months, to check our accuracy and to improve the estimates. It holds the facts about the listing that the estimate used: ZIP code, bedrooms, bathrooms, square footage, home type, year built, the location rounded to about a kilometre, days listed, asking rent, base rent, any price cuts and the original asking rent, whether it is furnished, short-term or in a managed building, the lease term, a posted special, an inquiry count if Zillow shows one, the amenities and fees the listing states (parking and garage, laundry, pets, pool, air conditioning, solar, appliances, HOA fee, deposit and application fee, whether utilities are included, lot size, stories, view) and the walk, bike and transit scores shown on the listing page, a sale price from the listing's own history when one anchors the estimate, whether it was listed by an owner or came from a corporate feed, whether it was relisted, a seasonal window if the listing has one, when the estimate was made, our estimate, offer and likely settling point, how confident we were and how much local data we had, a random quote id, and whether the request came from a search card or an opened listing. It also holds a one-way listing id, made from the listing's Zillow id with a key that only our server has, so the same listing scored by anyone counts once and nobody outside can turn the id back into a listing. It has no address, no exact coordinates, and no install identifier: it records that a listing was scored, not who scored it. While sharing is on, the listing snapshot you share carries your install identifier and a timestamp, so the two could in principle be matched; we do not match them, and with sharing off there is nothing to match. Scoring records from all users train the model; training tables and models built from a record are kept after the record itself expires, and carry none of its fields individually. The version history below marks when this began. If you later report what happened with that offer while sharing is on, your report carries the quote id and your install identifier, which links that one scoring record to your install. With sharing off, reports carry the quote id only.

Sent only if you turn on sharing

When you install Lowball, and the first time the panel appears, it asks whether you want to share the listings and search results you view to improve estimates for everyone. Nothing in this section is sent unless you say yes. If you do, the extension sends:

• A snapshot of each rental listing you open, at most once per listing per day. It contains the listing facts listed above plus base rent and fees, the tax-assessed value, lease term, laundry, parking and cooling features, photo count, posted specials, the number of inquiries Zillow shows for the listing, whether it is listed by the owner, and our own furnished and short-term flags, minus the description text and Zillow's rent estimate.
• The result cards on each rental search page you load: for every card, the listing id, street address, city, ZIP, coordinates, asking rent, last price change and date, beds, baths, square footage, home type, year built, and days on Zillow; for apartment buildings, the name, page link, units available, and each floor plan's starting rent. Not your search terms, filters, or map position.
• When Zillow loads the pins for the area on your map, the same card fields for each pin that carries them.
• For apartment buildings, the building name, ZIP code, unit list, specials, and lease length.
• A record of the panel actions you use (copy, flag, counter), with the listing's id and page path.

Shared search cards and map pins are also used, for up to 45 days after they were last seen, as the comparable rentals behind other people's estimates in the same area, which is how a city nobody has scored before gets a local estimate. The comparables table in the panel can show a shared listing's street address and rent, both of which are on its public listing. Nothing about who shared it is attached.

Each of these is tagged with a random install identifier. That identifier is a random string created by the extension and stored only in your browser's extension storage. It is not derived from your Google account, email, device, or anything else about you. We use it to count distinct installs, to tell one person's views apart from another's when weighting data, and to find your data if you ask us to delete it.

You can turn sharing off at any time with the switch on the extension's welcome page, in its popup, or in the panel footer. Turning it off stops all sending immediately. Data already sent stays on our server until it expires or you ask us to delete it. Your install identifier is shown in the "Wrong? Flag it" form in the panel, where you can also reset it. Uninstalling the extension deletes the identifier and your sharing choice from your browser; reinstalling creates a new identifier.

Sent when you use the feedback form

The "Wrong? Flag it" form sends what you enter: the reason you pick, the optional note, the amounts you offered and the landlord accepted, plus the listing's facts, our estimate, and the listing's page address. Your install identifier is attached only while sharing is on, so the entry can be deleted on request; with sharing off the entry carries no identifier. This is sent when you press Send, whether or not sharing is on.

Please do not put names, phone numbers, emails, or other personal details in the note. Notes are capped at 500 characters, and anything that looks like an email address or phone number is removed before saving. We delete any note on request.

Sent	Never sent
Listing price, size, address, location, days listed, price history, specials, unit lists	Your name, email, phone, or any account
If sharing is on: listing snapshots, copied-offer records, and a random install identifier	Your search terms, filters, saved homes, or browsing outside zillow.com
If you use the feedback form: what you enter, with the listing and our estimate	The listing description text, Zillow's rent estimate, device identifiers, your own location, your Zillow login

Chrome Web Store user data policy

Under the Chrome Web Store's definitions, the zillow.com pages you view are "web browsing activity" and the listing facts on them are "website content." Lowball collects them only for the feature described on its store page and in the extension itself: rent estimates and offers on the listings you open, sharpened by the listings and search results you choose to share. Sharing is off until you turn it on, and the extension asks for your consent inside its own interface, with a specific action, before it sends any of it. If what sharing sends ever changes, the extension asks again before sending anything new. We do not sell user data, transfer it to third parties except the processors named below, or use it for advertising, creditworthiness, lending, or any purpose unrelated to the feature. Lowball's use of information received from Google APIs will adhere to the Chrome Web Store User Data Policy, including the Limited Use requirements.

Server logs

Our server runs on Fly.io in the United States. Every request to it carries your IP address. We do not keep request logs that contain IP addresses; the address is held in memory for a few minutes to limit request rates, and our own log line per request records only the path, timing, and result. Fly.io may keep brief infrastructure logs containing IP addresses under its own privacy policy. This website is hosted on GitHub Pages, which records visitor IP addresses in its own logs under GitHub's policy.

Website analytics

This website (not the extension) uses Microsoft Clarity to see how visitors use its pages: page views, clicks, scrolling, and recordings of how a visit moved through a page. Clarity sets cookies to recognise a returning visitor and receives your IP address, browser and device type. It hides what you type into form fields, so the email on the renting-or-buying form is not recorded. Microsoft processes this data under the Microsoft Privacy Statement. We use it only to improve the website, never for advertising. You can block it with your browser's cookie or tracker settings; the website works the same without it. The extension never loads Clarity.

This website also loads the Google Ads tag, only to count how many visitors who arrived from one of our Google ads went on to finish the renting-or-buying form (a visit to the page shown after it). The tag sets cookies and sends Google the page address, your IP address and a click identifier from the ad. We have turned off Google's ad personalization and remarketing for it, so we do not build audiences from visits or show you ads based on them. Google processes this data under the Google Privacy Policy. The email you enter on the form is never sent to Google. You can block it with your browser's cookie or tracker settings; the website works the same without it. The extension never loads the Google Ads tag.

Personal information, plainly

We do not collect names, emails, phone numbers, or account details, and we do not want them. Three things we handle can count as personal information under California law, and we treat them that way: the random install identifier, IP addresses in our host's logs, and anything personal you choose to type into the feedback note. Everything else we handle describes a rental listing, not a person.

One thing worth spelling out, because it looks like an exception and is not: when you copy a drafted message, Lowball signs it with the name and phone number Zillow already shows in the contact form on that page, so you do not have to fill in a placeholder. That happens inside your browser, at the moment you press Copy. The name and number are not stored, not kept between pages, and never sent to our server. If the page does not show them, the message keeps the placeholders for you to fill in yourself.

How we use data

• Listing facts are used to compute the estimate you see and to build and improve the estimates: comparable rentals, price-cut patterns, vacancy patterns, and coverage in areas we do not yet model.
• Feedback and reported outcomes are used to correct estimates.
• The install identifier is used to count installs, weight shared data, and honor deletion requests.
• We may publish aggregate market statistics, such as median asking rent or the share of listings that cut price by ZIP code. We may also license aggregate statistics like these to other companies. Aggregates never contain install identifiers, individual view records, notes, or anything that identifies a person, and we publicly commit not to try to re-identify anyone from them and to require the same of anyone we share them with. We only publish a statistic when it is built from at least 20 listings, and we only license one built from at least 50, in both cases with no single building or owner making up more than half of it.

The extension does not sell or share personal information (the website's optional renting-or-buying form is the one exception, described in its own section), we do not use any data for advertising, we do not use it to decide anyone's creditworthiness or eligibility for anything, and we do not let anyone read individual records except to run the service, investigate abuse, or comply with law.

Who else sees it

Fly.io hosts our server and stores the data files. Tigris Data, an object-storage provider, holds a nightly backup copy of the same files; our server deletes backup files on the same schedule it deletes the originals. GitHub hosts this website, Microsoft Clarity measures how the website is used, and Google counts form completions that came from our ads (see "Website analytics"). Fly.io, Tigris and GitHub are not allowed to use the data for their own purposes; Microsoft and Google handle the website data they receive as described in "Website analytics". To build the estimates, the operator periodically downloads shared data to a computer under the operator's control and deletes that copy after it has been merged into the anonymous training set. We share nothing else with anyone, except aggregate statistics as described above, or if required by law. Lowball is not affiliated with, endorsed by, or sponsored by Zillow Group, Inc. Zillow and Zestimate are trademarks of Zillow Group, Inc. Listing data belongs to its listing sources. Use of Lowball is also governed by our Terms of Use.

How long we keep it

• Scoring records (listing-level, identity-free, described above): 12 months, then deleted.
• Shared listing snapshots, search-result and map cards, and panel-action records: 24 months, then deleted or reduced to aggregates that carry no identifier. The backup copy expires on the same schedule.
• Feedback form entries: 24 months, then deleted.
• Your sharing choice and install identifier: in your browser until you reset them or uninstall.
• Deletion requests: completed within 30 days by a script that removes every stored row carrying your install identifier from our server and its backup. Rows already merged into the anonymous training set cannot be traced back to an identifier and are not affected.

Your choices and rights

Follow-ups and flags. When you answer a follow-up question (what happened after you sent a letter), check a landlord's counter, or flag an estimate, we receive that answer together with the listing's ZIP, bedroom count, and prices, whether or not listing sharing is on. If you type anything in the optional note box, we receive that text too; before it is stored, anything that looks like an email address, phone number or web link is replaced with a placeholder, so please leave out names and addresses. Your anonymous install identifier is attached only while sharing is on. We never attach the address or your name.

Anyone, in any state, can ask us what data we hold for their install identifier, ask us to delete it, or ask us to remove a feedback note. Email peterskotte@lowball.rent. For shared data, include your install identifier from the panel's feedback form; that is the only way we can find your records, and it is also the only proof of ownership we need. For a feedback note, tell us roughly when you sent it and which listing it was about. We answer within 30 days and we will never treat you differently for asking.

California residents have the right to know what personal information we collect and how we use it, to delete it, to correct it, and to be free from discrimination for exercising these rights. Because we do not sell or share personal information, there is nothing to opt out of on that front. If we ever changed that, this policy would say so and the extension would ask you first.

Our browser extension does not respond to "Do Not Track" signals, because the only tracking-like behavior it has, listing sharing, is off until you turn it on.

Security

All traffic between the extension and our server uses HTTPS. Data is stored on a private volume on Fly.io and in a private backup bucket, both accessible only to the operator, protected by account security and two-factor authentication. Nothing is perfect. If shared data or feedback is ever exposed, we will post a notice on this website within 72 hours of learning about it, and describe what happened and what we did.

Where data is stored, and who this is for

Our server and data are in the United States. Lowball is offered in the United States and is not distributed in the European Union or United Kingdom. If you use it from outside the United States, your data is processed in the United States under this policy.

Children

Lowball is for adults looking for a rental. It is not directed at children under 13 and we do not knowingly collect information from them. If you believe a child has sent us data, email us and we will delete it.

Changes

When this policy changes, we update the date and version at the top and keep prior versions listed at the bottom of this page. If a change affects what is shared, the extension will ask for your sharing choice again before sending anything new. If a change affects what is kept from every estimate, the extension shows a notice at the top of its panel until you dismiss it.

Contact

peterskotte@lowball.rent. See also the support page, which covers reporting an estimate that looks wrong and having your shared data deleted.

The renting-or-buying form on this website

If you fill in the short form on lowball.rent before installing the extension (or from the Deals page), we collect what you enter: whether you are renting, buying or selling, your timing, the area, bedrooms and budget or home type, whether an agent is already helping you, and, if you choose to give it, your email address. We do not ask for a phone number. We use it to send deal alerts for your area and to draft offers that fit your search.

If you tick the box saying a licensed agent may contact you, we may share your email and your answers with the kinds of businesses named beside the box: licensed real-estate agents or brokerages if you are buying or selling; property managers, landlords, and moving, internet or renters-insurance providers if you are renting. They may email you. Under California law that is a sale of personal information, and you can opt out at any time with the request below; we also honor the browser's Global Privacy Control signal, and an entry made with it on is never shared. We keep form entries for 24 months, then delete them. The form is separate from the extension: nothing the extension reads or sends is linked to it, and it never carries your install identifier. The extension itself does not sell data.

Do Not Sell or Share My Personal Information

Enter the email you gave on the form and we will stop sharing it and remove it from anything not yet handed to an agent. No account or verification needed beyond the address itself.

Do not sell or share

Listing watches (price-drop alerts) on this website

If you ask us to watch a listing, on the Watch page or on a card on the Deals page, we keep your email address, the listing's Zillow id, its ZIP code and link, the time, the consent text you ticked, whether your browser sent the Global Privacy Control signal, a random watch id, and the unsubscribe code in your alert link. We use them only to email you when that listing's price drops, when it leaves the market, or when it comes back. We use your address for nothing else, and we never sell or share it. No install identifier is attached, and nothing the extension reads or sends is linked to a watch. Every alert email has a link that deletes every watch for your address at once. Otherwise a watch is deleted 180 days after we last saw its listing, or 180 days after you made it if we never saw the listing. A deletion reaches our backup and our working copy at their next daily update. A copy of each alert email is kept for 30 days.

Checking a listing and "send me the link" on this website

On the Check page, the listing facts you type (rent, ZIP, bedrooms, bathrooms, size, type, days listed and, if you give it, the street address) are sent to our server to make the estimate. The facts are kept in the same listing-level scoring record as any other estimate, without your name, email or any install id; the street address is used only to keep that listing out of its own comparables and is not stored. If you ask us to email you the Lowball link, we send that one email through our email provider, Resend, and do not store your address: to stop the same address being emailed twice in a day we keep a one-way code made from it, in memory only, for 24 hours. We never use the address for anything else.

If you paste a Zillow link instead, the page first looks the listing up in a file of listings published on this website, which sends nothing about you. If the listing is not there, the page sends its listing number to our server. The server looks for it among listings shared by extension users in the last 45 days and, if it is not there either, reads that one listing from Zillow through our data provider, Apify, and returns its public facts: rent, size, location, price history, description and lease term. Those facts are kept in memory for a day so the same listing is not read twice; nothing about you is attached to them. To limit how many listings one visitor can have read, the server counts lookups per IP address in memory, and the count is cleared every day.

Version history: v4.6, October 25, 2026 (this version): a pasted link to a listing we do not have is looked up among shared listings, or read from Zillow by our server; the extension is unchanged. v4.5, October 25, 2026: the Check page and the one-time "send me the link" email; the extension is unchanged. v4.4, October 23, 2026: listing watches and price-drop alerts on the website; the extension is unchanged. v4.3, October 21, 2026: the website loads the Google Ads tag to count form completions from our ads, with ad personalization off; the extension is unchanged. v4.2, October 21, 2026: the website uses Microsoft Clarity analytics; the extension is unchanged. v4.1, September 21, 2026: an opened listing's request carries nearby listings from your loaded search results as comparables, used once and not kept; shared cards and pins serve as comparables for others for up to 45 days. v4, September 14, 2026: the website's renting-or-buying form and the Do Not Sell or Share request. v3.2, September 14, 2026: scoring records became listing-level and identity-free, and train the model. v3.1, September 10, 2026. v3, September 10, 2026. v2, September 9, 2026. v1, September 9, 2026 (initial).