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Privacy Policy

KAI-ching is a free, independent New Zealand grocery price-comparison tool at kaiching.co.nz. This page explains what personal information we collect, why, and your rights under New Zealand's Privacy Act 2020. Plain English, no surprises.

Who we are: KAI-ching is a personal project run by Magdalena Polus, Crofton Downs, Wellington, New Zealand. "We" on this page means Magdalena, who holds the information described here and can be reached at hello@kaiching.co.nz.

What we collect, and why

• Your email address, if you give it to us. That's when you subscribe to the newsletter, unlock the AI features with your email (which also signs you up to the weekly savings email), or ask to be notified about an upcoming feature. We store it with our email provider (Mailchimp) so we can send you the weekly savings email. Signups use double opt-in – we email a confirmation link first, and you can unsubscribe anytime via the link in any email.
• Your account, if you sign in. Signing in is optional; see Accounts & sync below for exactly what's stored.
• Email newsletter analytics. Our newsletters, sent via Mailchimp, include standard open and click tracking so we can see how many people opened an issue and which links were useful. This applies only to the emails we send, not to the website.
• Feature interest (no personal data). When you tap "I want this" on an upcoming feature, we record only which feature and store you were interested in – never your email or anything identifying – so we can gauge demand. Asking us to notify you is a separate, optional step (see above).
• Website usage analytics. We use Cloudflare Web Analytics and Umami, which are privacy-first: no cookies, no cross-site tracking, no personal identification. They only tell us aggregate things like how many people visited, which pages and sections of the app are popular, and where visitors came from. Umami counts a visit to each section of the app (Browse, My Trolley, Assistant and so on) by its name only, and a few anonymous actions (like sending a split or scanning a receipt), never what's in your trolley, and doesn't count you at all if your browser sends Do Not Track. If you arrive via a campaign link (say, from our newsletter or a social post), we also count which campaign brought you – just the campaign label, nothing about you.
• On-device data, when you're not signed in (we don't collect this). Your trolley, preferences, budget, saved shop and watchlist, your “I already have” list, your savings history (for each shop: the day, town, stores, items, prices and how the saving was worked out), the receipts you keep and, if you keep them, their photos are stored locally in your browser on your own device. When you're not signed in, they never leave your device or reach us, except the preferences and “I already have” list sent with a "Build my shop" or Recipes request and the receipt photos you scan (see AI features below). Clearing your browser data, or "Clear this device" (under Your data on the Savings page), removes them. If you share a trolley link, its items are written into the link itself, so anyone you send it to can see them. A shopping-list link works the same way: it holds the list's items and quantities (and your town), so anyone with the link can see them. The ticks you make on a shopping list stay on the device you tick them on: they aren't synced to your account or sent to us.
• Barcode scanning. If you scan a product barcode in-store, your camera is used only on your device to read the barcode. No camera images are sent to us.
• The browser extension, if you install it. It sends your trolley to the supermarket you choose. We count each send (which supermarket, nothing about you or your items) and, only if you turn on its optional savings tracking, receive a short saving report for each order it spots, with nothing in it that identifies you. See The browser extension below for exactly what it reads, keeps and sends.
• Android app testers, if you join the tester group. The tester group is a Google Group run by Google. Joining it gives us the name and email address you join with, which we use only to invite you to test the Android app and send test updates. They aren't added to the newsletter or shared, and you can leave the group (and the test) any time. Feedback you send through Google Play or by email is used only to improve the app. See Help test the Android app.
• Price-drop alerts (push notifications), if you turn them on. Alerts need an account. When you turn them on, your browser or phone gives us a push address (a long web address plus encryption keys, created by your browser's push service: Google for Chrome and Android, Apple for Safari and iPhone, Mozilla for Firefox). We store it with your account so we can send you a notification when something on your watchlist gets cheaper in your town, and we keep a note of the price we last alerted you about so we don't repeat ourselves. The notification itself names the product and the new price, and it passes through that push service on its way to you. Turning alerts off, signing out on that device, or deleting your account removes the push address.
• AI features. If you use "Build my shop", the text you type (which may include household or dietary details you choose to share) is sent to our AI provider (Anthropic) to generate your result, together with your saved preferences: household size, any dietary choices, budget, main goal and preferred or avoided stores. These go with every "Build my shop" request, signed in or not, even if you don't type them; you can change or reset them under Preferences. If you use Recipes, the choices you tap (appliances, dietary requirements, pantry items, cuisine and servings) are sent to Anthropic to suggest recipes. Both also send your “I already have” list (the things you've told us you already have at home, by name), so the assistant can leave them out of what you buy, or, with Recipes' "Use what I have", suggest recipes that use them up. In both cases the result is returned to you and we don't store your text, preferences, choices, list or AI requests. "Your deals" doesn't use AI: it's worked out on your own device from our prices. If you use "Scan a receipt", your device first makes a smaller copy of the photo (which also leaves out the camera's details, such as where it was taken), and that copy is sent to Anthropic to read (if your browser can't make the copy, the original photo is sent, and no photo can be kept); we ask it to extract only store, date, items and total, and to ignore any card or loyalty numbers or names. Nothing from the receipt is kept unless you choose to keep it (see Receipts you keep). Please don't upload anything you wouldn't want processed, and crop out personal details from receipts where you can. AI suggestions can be wrong, so always check product labels for allergens.
• Receipts you keep (optional). After a scan you choose: add it to your savings, keep the receipt without counting it, or discard it (which keeps nothing, photo included).
  • What's kept. What was read from the receipt: the supermarket chain (not the branch or address), the date, each line as printed (with any long numbers removed), quantities and prices paid, the product we matched each line to, and our comparison (average prices in your town on the day you scanned it, and when those prices were checked). And the photo, unless you untick "Keep the photo with this receipt": it's the smaller copy described above, not your original.
  • Card digits. Receipt photos can show the last digits of a card, or a loyalty number. If you'd rather not keep those, untick "Keep the photo" and only the details read from it are kept.
  • Where. When you're not signed in, only on that device (in your browser's storage). When you're signed in, the details sync with your account and the photo is kept in private file storage in your account (Supabase, our database provider). A photo kept while you were signed out moves to your account the next time you sign in on that device, and is then removed from the device.
  • Who can see them. Only you. The file storage is private: each account can only reach its own photos, there are no public links, and a photo is shown through a link that stops working after two minutes. We don't look at your receipts or photos, except to fix a problem you ask us to look into, and none of our tools read them. They aren't used for anything else.
  • How long. Until you delete them. On the Savings page you can delete a kept receipt and its photo at any time, or clear your whole savings history (a photo kept in your account can be deleted while you're signed in). "Delete my synced data" and "Delete my account" delete them from our servers, photos included, and "Clear this device" removes the ones on that device. We keep your 52 most recent receipts; older ones are deleted automatically, with their photos.
  • What you buy can say something about your health or household, so delete any receipt you'd rather not keep, or clear your savings history. Backups you download (Back up, under Your data) include the receipt details but not the photos.
• Basic technical data. Like any website, our server briefly handles technical data such as your IP address, used only to keep the service running and to apply fair-use limits (on the AI, and on how often one address can send forms or saving reports). It isn't used to identify you and isn't kept long-term.

Accounts & sync

You don't need an account to use KAI-ching. If you choose to sign in:

• How sign-in works. You sign in with your email and a password, or with a one-time sign-in link we email you. Sign-in is handled by Supabase, our database provider; your password is stored only in scrambled (hashed) form and we never see it. Signing in doesn't sign you up to the newsletter.
• What we store. Your email address and an account ID, plus a copy of the app data you'd otherwise keep only in your browser: your trolley, your saved and regular shop, your savings history (for each shop: the day, town, stores, items, prices and how the saving was worked out), the receipts you keep and their photos if you keep those (see Receipts you keep), your preferences (including your name if you enter one, your household and any dietary choices), your budget, your town, your watchlist, your “I already have” list, and whether you've unlocked the AI features. Dietary choices can say something about your health or beliefs, so only pick the ones you're comfortable having stored. What you buy can too, so delete any receipt you'd rather not keep, or clear your savings history, on the Savings page.
• Why. So your trolley and settings follow you between your devices. Signing in also unlocks the AI features. We don't use your synced data for marketing.
• Where. Supabase stores it for us (receipt photos in its file storage) and may store it outside New Zealand. Access is locked down so each account can only read and change its own data.
• How long. We keep it until you delete your account, or until you delete your synced data (your account stays). Item details are kept for your most recent shops and receipts; older shops are kept as totals. You can delete a kept receipt and its photo, or clear your savings history, at any time. Signing out stops syncing on that device.

Deleting your account

You can delete your KAI-ching account at any time, on the website or in the Android app:

• In the app: sign in, tap the account button at the top of the page (it shows your email address, or a sync icon on a phone), and choose Delete my account. This immediately and permanently deletes your account (email address, sign-in details and account ID) and everything synced to it: your trolley, saved and regular shop, savings history, kept receipts and their photos, preferences, town, watchlist, “I already have” list, price-alert history and push addresses.
• By email: if you can't sign in, email hello@kaiching.co.nz from the address you signed up with and we'll delete it within 30 days and confirm when it's done.
• What stays: anything stored only on your own device stays there until you clear your browser or app data, or use "Clear this device" (under Your data on the Savings page). The weekly email newsletter is separate: unsubscribe with the link in any email. Anonymous counts that were never linked to you (such as which campaign brought a visit) aren't affected, and neither are the extension's saving reports, which aren't stored with your account (they're deleted 12 months after we receive them). The savings they added to your savings history are part of your synced savings record, so they're deleted from your account with it.

The browser extension

The KAI-ching Trolley Sender is an optional extension for desktop Chrome and Edge. More about it, including its permissions: extension privacy.

• Sending a trolley. When you click Send, the extension sends the product codes and quantities in your trolley only to the supermarket you chose (woolworths.co.nz, paknsave.co.nz or newworld.co.nz), into your own trolley there. "Send the split" does the same for a split shop: each supermarket gets only its own part, in its own tab. The extension never sees your supermarket password and never checks out. Pak'nSave's and New World's trolley reply can include your delivery address. The extension only reads the product lines and never keeps or sends the rest. When a send starts, the KAI-ching page counts it (which supermarket, and for a split, how many supermarkets), nothing about you or your items. Before and during each send, when you turn savings tracking on, and (with it on) when you open KAI-ching, the extension downloads a small on/off file (extension.json) from kaiching.co.nz, so we can pause it if needed. Like any web request, that shows your IP address to our host. Nothing else about you or your trolley is sent, and, like other technical data, the address isn't used to identify you or kept long-term.
• Savings tracking (optional, off unless you turn it on). You can turn on "Track my savings" in the extension's menu, or when it asks after a send (it asks at most twice, at least two weeks apart). Only then, and only for 7 days after you send items from KAI-ching, it watches for the order-confirmation page on woolworths.co.nz, paknsave.co.nz or newworld.co.nz in that browser. When you place an order and its confirmation page appears straight after checkout, it reads that one order's product list (product codes, quantities, whether the order went through and when it was placed) from the supermarket's site, on your computer. A confirmation page you open later, from your order history or a link, isn't read or counted. (To notice these pages, the extension's script on those three sites checks the address of the page you're on, whether or not tracking is on; that check reads nothing else from the page and sends nothing off your computer.) It works out which of the items it sent you ordered, and roughly how much you saved compared with buying them at the cheapest single store, using KAI-ching's prices when you sent them and before any extra delivery or pick-up fees (each part of a split is its own order). On Pak'nSave and New World it also notices when you start editing an order, so it can re-read that order when you save the change. It only reads: it never changes anything on the supermarket's site while it's watching. On Woolworths it asks only for the product list, the order's status and when it was placed; on Pak'nSave and New World the supermarket's reply may also include details such as your delivery address and payment details, which the extension ignores and never stores or sends.
• What stays on your computer. While tracking is on, the extension keeps in your browser: the product codes, quantities and estimated savings of the items it sent, for up to 7 days; a scrambled reference to each order it has counted, with that order's saving figures and, for each product it sent, a scrambled product code with the quantity already counted, for 30 days, so the same order isn't counted twice, even if you change it; the random value used for those scrambles; and any saving waiting for KAI-ching to pick up, for up to 30 days. While you're editing a Pak'nSave or New World order, it keeps that order number in the browser's temporary memory for up to 24 hours (cleared when you close the browser), so it can re-read the order. If you haven't decided about tracking yet, it keeps each send's product codes, quantities and estimated savings (never an order number) in the browser's temporary memory for up to 24 hours (cleared sooner if you close that tab or the browser): turn tracking on while they're there and that send is included; otherwise tracking starts with your next send. It also remembers your choice, and how many times it has asked and when. It never keeps your name, address, payment details, the prices you paid or your town.
• What KAI-ching receives. The extension never sends a saving to us itself. The next time you open KAI-ching, the page asks the extension for any saving it found, adds it to your savings history (the Savings page) and sends our server a report of only: the supermarket; how many of the items it sent had a saving, and how many of those you bought; the estimated saving; whether it was a split shop; the extension's version number; and a random code for that order (made up by the extension, not your order number), with a revision number if the order is changed later. Our database adds the date (the day only, no time). The report contains nothing that identifies you: never your name, address, payment details, order number, products or prices. If you're signed in to KAI-ching, the saving is also added to your savings history in your account, which is stored with your account as before (see Accounts & sync). Your savings history keeps each order as its own entry: the supermarket, the day it was recorded, the estimated saving, how many items were sent and bought, whether it was a split shop and its revision number. All of these are also in the report we receive, so the two could be matched; we don't match them. The order's random code is never synced to your account (the page keeps it only on that device, so the same order is never added to your savings twice), and we don't store reports with accounts.
• Who handles it. Our web host, Railway, runs the server that receives it, and our database provider, Supabase, stores it for us. Like any website, our web host sees your IP address when the page sends the report. Our server uses it only in memory, to limit how many reports can come from one address, and doesn't store it with the saving. Supabase gets the report from our server, not from your browser.
• How long. Saving reports are deleted automatically 12 months after the day we receive them.
• Why. So you can see your own savings, and so we can see, in total, whether the extension is worth keeping. The reports are never sold, never used for advertising and never given to supermarkets or anyone else. Our use of information received by the extension adheres to the Chrome Web Store User Data Policy, including the Limited Use requirements.
• Your choice. Savings tracking is optional. The extension sends trolleys just the same with it off, and saying no costs you nothing. Turn it off any time in the extension's menu: that deletes what it was keeping for tracking straight away. The menu also shows what it's watching (how many sends, and until when), and "Forget everything" deletes that data while keeping your choice. Removing the extension deletes all of it. Savings already added to your savings history stay there, as part of your own savings record.
• Seeing or correcting it. The savings added to your savings history are part of your own savings record: on your device, and in your account if you're signed in, where you can see them and delete them with the rest of your synced data (see Deleting your account). What the extension keeps stays on your computer, where you can delete it as above. The reports our server receives hold nothing that identifies you and aren't stored with your account, and we don't try to match them to anyone. Questions: hello@kaiching.co.nz.

Who we share it with, and where it goes

We don't sell or rent your information to anyone. We use a small number of trusted providers to run the service, and most of them store and process data outside New Zealand, mainly in the United States. Each is bound by its own privacy commitments and data-processing terms, which provide safeguards comparable to those required by New Zealand law. By using these features you consent to your information being processed overseas as described.

• Mailchimp (Intuit, USA): the email newsletter; holds your email only if you give it, and handles newsletter open/click analytics.
• Supabase: our database provider; handles sign-in and stores your account and synced data if you sign in (including, in its file storage, the receipt photos you keep), and the saving reports (which hold nothing that identifies you) from the extension's optional savings tracking. It may store this outside New Zealand.
• Anthropic (USA): powers the AI features (Build my shop, Recipes and receipt scanning); processes your request text, preferences, choices or receipt image to generate a result.
• Cloudflare (USA): privacy-first, cookieless analytics and security.
• Umami (data stored in the European Union): privacy-first, cookieless analytics: counts of visits to each section of the app, and of a few anonymous actions.
• Google (Google Groups and Google Play): only if you join the Android tester group; it runs the group and the test (see Android app testers).
• Google, Apple or Mozilla push services: only if you turn on price-drop alerts; they carry each notification to your device (see price-drop alerts).
• Railway (USA): hosting. Our web server runs there, so it handles every request to kaiching.co.nz, including the extension's optional saving reports.
• esm.sh: a script CDN that serves two open-source code libraries the app loads (the sign-in library and the barcode reader). Like any server your browser fetches files from, it sees your IP address and browser details when it does.
• Supermarket image servers: product photos load directly from the supermarkets' own image servers (Woolworths and Foodstuffs), so your browser contacts them to show a photo, which shares your IP address and browser details with them, as any web image does.

How long we keep it

We keep your newsletter email for as long as you're subscribed, and remove it when you unsubscribe or ask us to. If you sign in, your account and synced data are kept until you delete your account. Feature-interest records (which hold no personal data) are kept only as long as useful for gauging demand. The extension's saving reports are deleted 12 months after the day we receive them. Technical data like IP addresses is short-lived and not retained long-term. We don't store AI request text, the preferences sent with it or recipe choices. A scanned receipt's details and photo are kept only if you choose to keep them, until you delete them (see Receipts you keep).

Your rights

Under the Privacy Act 2020 you can ask to see, correct, or delete the personal information we hold about you: your newsletter email and, if you've signed in, your account and the data synced to it. Unsubscribing removes you from the list, or you can email us and we'll sort it. The extension's saving reports hold nothing that identifies you and aren't stored with your account (see The browser extension); the savings they add to your savings history are part of your synced data if you're signed in. If you're ever unhappy with how we've handled your information, you can complain to us first, and then to the Office of the Privacy Commissioner (privacy.org.nz).

Data breaches

If a privacy breach occurs that could cause you serious harm, we'll notify you and the Office of the Privacy Commissioner as required by Part 6 of the Privacy Act 2020.

Cookies

The website doesn't use tracking or advertising cookies, and our website analytics are cookieless. If you sign in, your browser keeps a sign-in token so you stay signed in; it's used only for that. Emails we send via Mailchimp do include standard open/click tracking, as noted above.

Changes

If this policy changes, we'll update this page and the date at the top.

Contact

Questions or requests, including to see, correct or delete your information: Magdalena Polus, hello@kaiching.co.nz (Crofton Downs, Wellington, New Zealand).