Which extension should you choose to track the price of a product?

A price-tracking extension shows how a product’s price has changed, and lets you know when it drops. It helps you tell whether a displayed discount matches a genuinely lower price. Extensions do not cover the same sites, do not keep history the same way and do not declare the same data.

On the same day, on their official pages, we checked the same information for each one.

The tool for this

Nexily Price

E-commerce price history and drop alerts.

Discover Price

Free: 5 products

The extensions, criterion by criterion

Nexily Price

• Sites covered (according to the publisher): The product pages you open in online shops
• History and alerts: History recorded on each visit, and in the background for tracked products (except on sites that block it, such as Amazon); alerts below the threshold you set. Free: 5 products, 30 days. Pro: unlimited, 365 days
• Account: No
• Browsers: Chrome, Firefox, Edge
• Price for you: Free; Pro at €19, lifetime licence, one payment
• Data declared on the Chrome listing: “User activity”. Its listing says your product list stays on your machine
• Extension launched in 2026.

Keepa

• Sites covered (according to the publisher): Amazon sites in 10 countries, including amazon.fr
• History and alerts: History charts; target-price and back-in-stock alerts; no history length stated on the listing
• Account: No, to get started
• Browsers: Chrome, Firefox, Edge
• Price for you: No price shown on the extension listing; Keepa Pro plan at €29/month, presented for professional sellers
• Data declared on the Chrome listing: “Personally identifiable information”; according to its policy, the extension may send Amazon product information to its servers, an option you can turn off

The Camelizer (camelcamelcamel)

• Sites covered (according to the publisher): Amazon United States, Canada, most of Europe, Australia
• History and alerts: History from the camelcamelcamel.com database; email alerts
• Account: Not stated on the listings
• Browsers: Chrome, Firefox, Edge
• Price for you: Free: “a free Amazon price tracker” according to its website
• Data declared on the Chrome listing: “Personally identifiable information” and “Website content”

DeaLynx

• Sites covered (according to the publisher): Amazon, Fnac and Cdiscount according to its listings; 14 retailers according to its website
• History and alerts: History and lowest recorded price; alerts through a dashboard with an account
• Account: No for history; yes for alerts
• Browsers: Chrome, Firefox, Edge
• Price for you: Free extension; tracking service from €0 to €39.99/month
• Data declared on the Chrome listing: Declares it collects no data. According to its policy, the extension sends the public details of the product page to dealynx.fr

Courbeprix

• Sites covered (according to the publisher): Amazon (9 countries), Fnac, Cdiscount
• History and alerts: History built from the prices your browser sees; target-price alert, up to 15 products
• Account: No
• Browsers: Chrome (Edge announced as “coming soon”)
• Price for you: Free
• Data declared on the Chrome listing: “Web history” and “Website content”; its policy says “Nous ne collectons aucune donnée de navigation” (we collect no browsing data)

PriceGuard

• Sites covered (according to the publisher): 20+ sites, including Amazon, Fnac, Cdiscount, Boulanger, Darty, and sites that use Schema.org tags
• History and alerts: 90 days; up to 3 years on Amazon with a free Keepa key; alert if the struck-through price never existed
• Account: No
• Browsers: Firefox
• Price for you: No price
• Data declared on the Chrome listing: — (not on Chrome). Its Firefox listing says it does not need to collect data

What about comparison sites?

idealo and LeDenicheur compare prices across many retailers on their website and app, but we found no extension for either of them on Chrome, Firefox or Edge on the day we checked. They are therefore not in the table.

When to choose another tool

• You mostly buy on Amazon and want a long history from day one: Keepa and The Camelizer show history from their own database, without waiting for your visits. Nexily Price, Courbeprix and PriceGuard build history from what you view (or, for PriceGuard, with a Keepa key on Amazon).
• You want to compare the same product across several retailers: DeaLynx and Courbeprix group the offers for the same product; idealo and LeDenicheur do it on their websites.
• You use Firefox and want up to 3 years of history on Amazon: PriceGuard, with a free Keepa key.
• You want to track products on all kinds of shops, with alerts in the browser: that is what Nexily Price was built for.

Our method

Checked on 25 October 2026, between 18:34 and 18:58 (Paris time), on the publishers’ public pages and the official store listings, without signing in and without installing anything. Each fact is kept with a dated screenshot. keepa.com and camelcamelcamel.com, protected against bots, were read the same evening in an ordinary browser; idealo.fr could not be viewed. When two pages from the same publisher do not say the same thing, we quote both. Facts are rechecked every three months.

Pages consulted: chromewebstore.google.com, addons.mozilla.org and microsoftedge.microsoft.com (listings Keepa, The Camelizer, DeaLynx, Courbeprix, PriceGuard, Nexily Price) · keepa.com/data · keepa.com/privacypolicy.html · camelcamelcamel.com · camelcamelcamel.com/camelizer · dealynx.fr/extension · dealynx.fr/tarifs · dealynx.fr/extension/confidentialite · courbeprix.fr · courbeprix.fr/confidentialite · ledenicheur.fr · recherches « idealo » and « ledenicheur » sur les trois stores.