Ask HN: Are there any apps to track grocery prices in local stores?
With tariffs kicking in and imports slowing, I want to track the local impact at my grocery stores. Does anyone have any suggestions? Would scraping websites of local grocers be sufficient? Any prior art?
There are barcode scanning libraries that specialise in scanning dozens or hundreds of barcodes in a single frame.
These are typically used to mass-import your competitors prices just by walking through the shop with a camera mounted on your shoulder. Or phone in a shirt pocket with the camera facing forward.
There’s a few white-label companies that offer these apps. Many of the barcode companies offer their own version of this app. They’re not usually available on the AppStores.
The reason for this is that each competitor requires slight customisation (font, price location relative to each barcode, etc) to get the best results.
I thought barcodes were effectively just "guids" that you could use for a lookup table or whatever to get pricing etc. Knowing what the product _is_ wouldn't tell you what the price is - you'd need the table.
I am not sure how the system for most grocery stores works now, but in the ancient past there was a central authority that set the prices for individual stores (so in Australia, the Coles or Woolworths all have individualised prices per store for items except for advertised sale items).
The computer in the store that drives the POS scanners then can print out the shelf label stickers and a poor sod goes and replaces the stickers on the shelves.
This is all a big secret of course, so asking a grocery store for their prices is going to get you nowhere.
You could try scraping the websites, but often the price for online shopping is different to what is in store.
Best bet would be to offer an incentive for people to scan their receipts into your app. I don't know what kind of incentive you could build to do that, maybe for every 5 receipts you could offer a coupon or something. Not much of an idea and a massive PITA, it would also only give prices on those things that people bought.
edit: also gets complicated for multi-item discounts or combination discounts
Safeway’s site is extremely aggressive with anti scraping. Even if you simply direct load a product url a single time you’re hit with a captcha. Try it - view any product page, and the change 1 character in the product id in the url. Instant captcha. Scrapers be damned.
Your grocery store would have significant data that it feeds its e-ink displays with. Capturing those updates could be fun if you’re looking for a project…
These are typically used to mass-import your competitors prices just by walking through the shop with a camera mounted on your shoulder. Or phone in a shirt pocket with the camera facing forward.
There’s a few white-label companies that offer these apps. Many of the barcode companies offer their own version of this app. They’re not usually available on the AppStores.
The reason for this is that each competitor requires slight customisation (font, price location relative to each barcode, etc) to get the best results.
How does it actually work?
The computer in the store that drives the POS scanners then can print out the shelf label stickers and a poor sod goes and replaces the stickers on the shelves.
This is all a big secret of course, so asking a grocery store for their prices is going to get you nowhere.
You could try scraping the websites, but often the price for online shopping is different to what is in store.
Best bet would be to offer an incentive for people to scan their receipts into your app. I don't know what kind of incentive you could build to do that, maybe for every 5 receipts you could offer a coupon or something. Not much of an idea and a massive PITA, it would also only give prices on those things that people bought.
edit: also gets complicated for multi-item discounts or combination discounts
Your grocery store would have significant data that it feeds its e-ink displays with. Capturing those updates could be fun if you’re looking for a project…