FeeLens

Privacy policy

Effective 2026-11-02. FeeLens is made by Norwell Systems LLC.

What the extension reads

On Amazon.com product pages the extension reads the page you have open: the product title, ASIN, price, package weight and dimensions, and the breadcrumb category. It uses them only on your device to calculate fees. It reads nothing on any other site and it does not fetch pages on its own.

What stays on your computer

Your cost, inbound and shipping inputs, your per-product edits, your default settings, your license key, your trial start date, your usage-count setting and the daily code described below are stored in the browser's extension storage. They are not synced to us.

What is sent to us

  • License checks. When you enter a license key the extension sends the key to our server to ask whether it is active, and checks it again when the last answer is more than 24 hours old. The answer is cached for 24 hours, and if our server cannot be reached the last answer stands for 48 hours.
  • Daily settings download. Once a day the extension downloads its settings from our server: the checkout links, the support link and the current fee table version. That request carries no identifier. The fee tables themselves are built into the extension.
  • Anonymous usage counts and lifecycle events. Described in full in the next section.

Anonymous usage counts

FeeLens sends a few small events so we can count how many people use it and spot broken versions. We call them anonymous because they carry no name, email, page content, page address, product, price, fee result or anything you type. They are linked to a daily pseudonymous visitor code, described below.

What FeeLens sends

  1. Usage events: "panel_view" when the FeeLens panel appears on a product page, and "calc" when a calculation runs. Each is sent at most once a day.
  2. Lifecycle events: install, trial start, trial end and purchase. Each is sent once per installation.
  3. Each event contains only the event name, the event type (usage or lifecycle), the product name (FeeLens), the FeeLens version and the date. Lifecycle events also carry a random installation id that FeeLens creates on install. Usage events do not carry the installation id. They carry an event id made of the product, the event name, the date and a random code made fresh each day, used only to drop duplicates.

What our server adds

  1. Our server, hosted on Cloudflare Workers, sees your IP address and browser type (user agent) with each event. It combines them with a secret value and the date to make a daily pseudonymous visitor code, so one person counts once per day. Your IP address and browser type are not stored with the event. The visitor code changes every day.
  2. Your country and network (the network number of your internet provider, called an ASN) are stored with each event. We use them to tell people from automated traffic.
  3. For rate limiting, our server may hold your IP address for up to 2 minutes.
  4. Cloudflare, our host, keeps request logs for our event server that include the IP address and browser type, for up to 3 days, which we use only to fix problems.

Retention, today

  1. Events, daily visitor codes and daily totals are currently kept with no fixed deletion date. Server health records are deleted after 30 days.

Turning usage counts off

  1. In the FeeLens panel, open Settings and switch off "Send usage counts". While it is off, FeeLens sends no usage events. License checks and the daily settings download continue, because FeeLens needs them to work.

Who receives it

  1. Only Norwell Systems LLC, through our server on Cloudflare Workers. We do not sell it, we do not use it for advertising, and we look only at totals.

Limited Use

FeeLens's use of information received from Chrome and the Chrome Web Store follows the Chrome Web Store User Data Policy, including the Limited Use requirements. We use this information only to provide and improve FeeLens's single purpose: showing estimated Amazon fees and profit on the product page you are viewing. We do not use or transfer it for advertising, we do not sell it, and we transfer it only as that policy allows. No person reads your individual data, except with your consent, for security, to comply with the law, or as anonymized totals for internal reporting.

Payments

Purchases are handled by Polar Software Inc. as merchant of record. Polar collects your email and payment details under its own privacy policy and sends us your email and the license key it issued so support can find your order.

Support

Messages sent from the support page carry the email and text you type. They are answered automatically from our documentation when possible and otherwise forwarded to a person at Norwell Systems LLC. We keep support threads for one year.

What we do not do

We do not sell data, run advertising, use tracking pixels, or read your Amazon seller account. The extension asks for access to www.amazon.com only, plus storage and a daily alarm.

Your choices

Switch off usage counts at any time in the panel's Settings. Uninstalling the extension deletes everything it stored. Email stack@norwellsystems.com to have your support threads or purchase record deleted; Polar handles deletion of payment records.

Contact

Norwell Systems LLC, stack@norwellsystems.com.

FeeLens is not affiliated with Amazon.com, Inc. Figures are estimates and are not guaranteed.