Open Trolay

Built for UK supermarkets

Know your trolley total before the till.

Trolay is a small web app for your phone. Snap each shelf price label and it keeps a running total as you shop — with and without VAT, in a shop with no signal.

Open Trolay Try the 15-second demo

Runs in your browser · Add it to your home screen · No account needed to start

  • Under 5 seconds an item
  • 20% VAT, handled
  • Works offline once installed

How it works

Three taps from shelf to total.

No typing a price list. Trolay is built around the one thing you already do in a shop: look at the label.

  1. TESCO EXPRESS Semi-skimmed milk 2 pints £1.45
    1

    Snap the shelf label

    Pick the store, open the camera and frame the price tag. One tap captures it — the reading happens on your phone, not on a server.

  2. Label read
    Description Semi-skimmed milk
    Price £1.45
    Tax Includes VAT
    2

    Check the reading

    The description, price and VAT flag are filled in for you. Anything uncertain is highlighted, so you only correct what actually needs it.

  3. Total incl. VAT £12.84
    £10.70 excl. £2.14 tax
    £2.16 left of £15
    3

    Watch the total

    Add, edit or delete and the sticky total updates immediately. Tap it to switch between incl. and excl. VAT; the budget bar turns amber at 90%.

Try it

The whole loop, in fifteen seconds.

Snap the simulated shelf label, check what was read, then add it. The trolley and the VAT maths are real — only the camera is pretend.

Interactive demo Step 1 · Snap
Tesco Express Free-range eggs 6 pack · medium £2.65 £2.65 each

A stand-in for the app's camera. In Trolay, this reads the real price tag on your phone.

Your trolley

  • Semi-skimmed milk £1.45 each · incl. VAT 1 £1.45
  • Sourdough loaf £2.80 each · incl. VAT 1 £2.80
Excl. VAT
£3.54
VAT (20%)
£0.71
Items
2
Budget left £10.75 of £15.00

A simulation built from the app's real VAT rules. No camera access, no account and no data leaves this page.

What's inside

Small app. The whole shop covered.

Everything is built around the running total — from the first label to the receipt check, and the history you keep afterwards.

  • The total is always in sight

    A sticky footer shows what you've spent, the tax and the item count. Tap the headline to flip between incl. and excl. VAT; Trolay remembers your choice.

  • Under five seconds an item

    The camera reads the label on the device. Low-confidence fields are highlighted, so you fix the exception rather than typing every price.

  • A budget that speaks up

    Set a budget when the trip starts — or later. The bar turns amber at 90% and red when you're over, before the till does.

  • Receipt check

    Enter or snap the till total at the end. Trolay shows the difference from its own total, so a misread label can't hide.

  • One trolley, two phones

    Invite someone to a single trip. They see the items and running total live, and can add or edit — your other trips stay private.

  • History, and a CSV if you want it

    Finished trips are listed by store and date with their receipt difference. Export one trip or the lot as a spreadsheet.

  • Barcodes when they help

    Scan a barcode and Trolay fills the description from an earlier trip, or looks it up when you have signal. Offline, it retries later.

Offline by design

Supermarkets are signal black spots. Trolay isn't.

Once it's on your home screen, the app opens without a connection. Prices are read on the phone, records are saved on the phone, and anything you change queues until you're back online.

See how to install it

  • Local-first, not cloud-first

    Stores, trips, items and photos live in the browser's own database. Every screen reads from there, so it behaves the same in a basement aisle as at home.

  • Changes wait their turn

    Every edit goes into an outbox. When you reconnect it syncs, and a shared partner's changes come back the same way — nothing is lost if you both shop offline.

  • Private by default

    Until you sign in, data never leaves the device. There is no analytics on the app, and only barcodes are sent to Open Food Facts for a name lookup.

  • Photos don't pile up

    Finishing a trip deletes its photos from every device — unless the receipt didn't match, in which case they're kept as evidence until you delete them.

Install in seconds

A website that behaves like an app.

No app store and no download queue. Open Trolay in your phone's browser, add it to your home screen, and it gets its own icon, a full-screen window and an offline cache.

  • Android

    Chrome
    1. 1

      Open shopping.trolay.com in Chrome.

    2. 2

      Tap the ⋮ menu in the top-right.

    3. 3

      Choose “Install app” or “Add to Home screen”.

    4. 4

      Confirm — Trolay appears with its own icon.

  • iPhone & iPad

    Safari
    1. 1

      Open shopping.trolay.com in Safari.

    2. 2

      Tap the Share button.

    3. 3

      Scroll down and tap “Add to Home Screen”.

    4. 4

      Tap “Add” — it opens full-screen, like an app.

  • Desktop

    Chrome or Edge
    1. 1

      Open shopping.trolay.com in Chrome or Edge.

    2. 2

      Click the install icon in the address bar.

    3. 3

      Or open the browser menu and choose “Install Trolay”.

    4. 4

      Launch it from your apps like any other app.

Open Trolay

Use Safari on iPhone, and Chrome or Edge on Android and desktop.

It works offline after the first load. Open it once with a connection; after that the shell and your data are cached on the device.

On iPhone, installing matters. Safari can clear data for sites you haven't used in seven days; adding Trolay to the home screen (or signing in) protects your trips. The in-app camera needs iOS 16.4 or later.

Questions

The practical bits.

Short answers about accounts, signal, tax, sharing and what happens to your photos.

Do I need an account?

No. Trolay works without signing in: stores, trips and history are saved on your own device. Signing in — with a passkey or an emailed link — is only for syncing across your devices and sharing a trip.

Does it really work with no signal?

Yes, once the app has loaded or been installed. Label reading runs on the phone, so capture works in a basement aisle. Changes are queued and sent when you reconnect; if you and a partner both shop offline, your edits merge when you are back online.

Where does my data go?

It stays in your browser until you choose to sign in. After that it syncs over HTTPS to a small service on trolay.com that you control. There is no analytics. Only barcodes are sent to Open Food Facts, to look up a product name.

Which shops and which country does it support?

Any shop, anywhere you can read a price label — but the tax model is UK-only for now: pounds sterling and 20% VAT by default. Both the rate and whether labels include VAT are editable per store. Other countries and currencies are planned.

Can someone else add to my trolley?

You can invite one person to a single trip by link. They see that trip’s store, items and running total live, and can add or edit items. Your other trips and stores stay private. A finished shared trip stays in both people’s history.

What happens to the photos of price labels?

They are proof while the trip is open. Finishing a trip deletes them from every device and from the server — unless the till receipt did not match the app total, in which case they are kept as evidence until you delete them. Descriptions, prices and barcodes are always kept.

Do I have to install it?

No. Trolay runs in the browser. Installing it to your home screen gives it an icon, a full-screen window and a cache that opens without signal. On iPhone, installing also stops Safari clearing the site’s data after seven days of non-use.

Can I get my shop out of the app?

Yes. Export a single trip or your whole history as CSV — one row per item with date, store, description, barcode, quantity, unit price, tax and line total. If you do not sign in, there is also a full JSON backup and restore.