Barcode Betty
961d29361b
- stores.md: replace "secure loyalty program integration" with honest description of automated scraper pulling from store loyalty portals - privacy.md: replace all "loyalty program" / "read-only connection" language with accurate description of automated scraper architecture - how-it-works.md: describe scraper architecture honestly; clarify USDA FoodData Central is historical baseline reference only, not part of live tracking; remove "(yet)" from receipt statement Co-Authored-By: Paperclip <noreply@paperclip.ing>
84 lines
3.3 KiB
Markdown
84 lines
3.3 KiB
Markdown
# How CartSnitch Works
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## The Core Idea
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Every product at the grocery store has two prices:
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- **Shelf price** — what you pay at checkout
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- **Unit price** — what you pay per ounce, per gram, per sheet, per load
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Most people compare shelf prices. Smart shoppers compare unit prices.
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CartSnitch tracks unit prices automatically — so you don't have to do the math yourself.
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---
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## How We Track Prices
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CartSnitch pulls pricing data from:
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- **Store loyalty portals** — Meijer, Kroger, and Target — when you connect your account, CartSnitch uses an automated scraper to pull your purchase history from the store loyalty portal
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- **Public manufacturer data** — packaging changes, suggested retail prices
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- **USDA FoodData Central** — reference data for package sizing baselines (used for historical size comparison only — not part of our live tracking system)
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We calculate unit price for every product we track:
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`Unit Price = Shelf Price ÷ Package Size`
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When a brand reduces package size — or a store changes its price — we catch it.
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---
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## What Is Shrinkflation Detection?
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Shrinkflation happens when a brand reduces the size of a product without lowering the price. The shelf price stays the same. The unit price goes up.
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**Example:**
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- 2021: Cereal at $4.99 for 18 oz → $0.277 per oz
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- 2024: Same cereal at $4.99 for 15.5 oz → $0.322 per oz
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Same price. 16% more per ounce. That's shrinkflation.
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CartSnitch monitors unit prices over time. When we detect a statistically significant unit price increase — whether from a size reduction, a price increase, or both — we flag it.
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---
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## How Price Alerts Work
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1. **You add a product** — Search for any product you buy regularly and add it to your tracked list.
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2. **We monitor unit prices** — Every time we detect a price or size change, we recalculate the unit price.
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3. **You get an alert** — If the unit price increases beyond a threshold, we notify you — so you can decide whether to switch products, switch stores, or just be aware.
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You choose what counts as significant. Some users set alerts for any change. Others only want to know about large unit price jumps.
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---
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## Store Comparison
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CartSnitch compares your total grocery basket across stores.
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When you connect your store accounts, we can see what you bought and where. We calculate the total cost of your typical basket at each store we support — so you know where you're getting the best overall deal.
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This is different from just comparing the price of one item. Some stores are cheaper on produce, others on pantry staples. CartSnitch shows you the full picture.
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---
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## What We Don't Do
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- **We don't collect receipts** — Store account connections give us enough data to track prices and compare baskets. Receipt-based tracking is being evaluated.
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- **We don't have every product** — Beta is limited to supported stores and categories. We're adding more every week.
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- **We don't affect shelf prices** — We show you the data. What you do with it is up to you.
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---
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## How We Protect Your Data
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- We read price data from your connected store accounts — we never see your login credentials
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- We store only the minimum data needed to calculate unit prices and compare baskets
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- We don't sell your data to third parties
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- You can disconnect your store account at any time and delete your data
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---
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## Ready to Start?
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[Sign up for beta →]
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