See every price change in your Amazon Cart at a glance — sorted, in one table.
CartLens is a free, open-source Chrome extension (Manifest V3) that tracks the price of every item in your Amazon Cart — including Saved-for-Later — and shows it in a clean, sortable price comparison table: product thumbnail and name (linked), previous price, current price, and percent change — so the best price drops (and the sneaky price increases) jump out immediately. It remembers prices between visits, so it builds each item's price history for you over time. No sign-up, no price-tracking account, no external service — it just reads the cart page you already have open and stores history locally in your browser.
- Fully automatic — the table appears as soon as you load your Amazon Cart page. No click required.
- Tracks Cart and Saved-for-Later — every item with a price shows up, each tagged with its section.
- Price history over time — CartLens records prices between visits, so it builds a running history for each item even if Amazon shows no change notice. Click any row to expand its full price history with timestamps.
- Product thumbnails — each row shows the item's image for quick recognition.
- Sortable columns — click any header (Product, Section, Prev Price, Current Price, % Change) to sort ascending/descending.
- Sorted by biggest change first — by default, items are ranked by percent change so the largest price drops surface immediately.
- Color-coded — price drops in green, increases in red, unchanged dimmed.
- Collapsible — click the heading to collapse the whole table out of the way.
- Per-item clear — dismiss any item to drop it (and its stored history) from the table.
- Works across Amazon storefronts — .com, .in, .co.uk, .de, .ca, .fr, .it, .es, .co.jp, .com.au, .com.mx, .com.br, .nl, .se, .pl, .sg, .ae, .sa.
- Private by design — runs entirely client-side. History is stored only in your browser's local storage. No data leaves your browser, no analytics, no external requests.
(coming soon — link will go here once published)
- Clone or download this repo.
- Open
chrome://extensionsin Chrome (or any Chromium browser — Edge, Brave, Arc). - Enable Developer mode (top-right toggle).
- Click Load unpacked and select the
cartlens/folder. - Visit your Amazon Cart — the table appears automatically above the existing price-change notices.
CartLens is a Manifest V3 content script. On each cart page it scrapes every
active and saved-for-later line item using Amazon's own data-asin /
data-price attributes (more reliable than the visible price spans), reading
the product link, image, and current price for each. It merges those prices into
a per-item history kept in chrome.storage.local, appending a new point only
when a price actually changes (capped at 50 points per item). Each row's
previous vs. current price gives the percent change, and the table is rendered
above Amazon's existing cart content. A debounced MutationObserver re-renders
when Amazon updates the cart asynchronously (e.g. as Saved-for-Later lazy-loads
on scroll).
No network requests, no remote code, no tracking — everything happens in the page you already have open, and history never leaves your browser.
Bug reports and PRs are welcome — see CONTRIBUTING.md.
Amazon frequently A/B tests its cart page markup, so selector breakage is the most common type of bug. If your table stops appearing, please open an issue with a sanitized HTML snippet of the "Important messages" section (strip your personal data first).
CartLens requests activeTab, scripting, and storage permissions, plus host
permissions scoped to Amazon cart pages only. Price history is stored locally via
chrome.storage.local and never transmitted anywhere. It does not collect or
transmit any data. See PRIVACY.md for the full policy (required for
Chrome Web Store listing).
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