About this product

See your real profit on every sale — before you list it.

FeeLens is a Chrome extension (Manifest V3) built for marketplace sellers. Click its icon any time to estimate fees and margin on a sale in seconds, or browse listings while a small overlay chip shows the estimated fee and net right next to the price.

WHAT IT DOES

• Popup fee calculator: enter item price, shipping charged, item cost and shipping cost, pick a channel, and instantly see total fees, net proceeds, profit after costs, and your margin % — with an ON TARGET / BELOW TARGET flag against the target margin you set.
• On-page overlay: a small dismissible chip appears next to prices on listing pages, showing the estimated fee + net for your default channel. It never touches page layout, and one click dismisses it. A customizable selector list controls how FeeLens finds prices.
• Settings page: four channel fee presets (Etsy-style, eBay-style, Amazon-style, own-store) — every percentage and fixed fee is editable and saved in your browser. Set your default channel, target margin %, and toggle the overlay on or off.

PRIVACY AS A FEATURE

Everything is computed locally in your browser. FeeLens makes no network requests of its own, sends no analytics, and transmits no browsing data anywhere.

IMPORTANT — READ BEFORE BUYING

• This is an UNPACKED extension: it is NOT listed on the Chrome Web Store. You install it once in about 2 minutes via chrome://extensions → Developer mode → Load unpacked. The package includes an illustrated Install & User Guide that walks you through every step.
• Fee presets are editable starting defaults, NOT official fee schedules. Fees change and vary by category — verify the current official fee schedule for your category and adjust the presets before relying on them.
• Works in Google Chrome (and other Chromium browsers that support Manifest V3 unpacked extensions). A planning tool, not financial advice.

What's included

• feelens-extension/ — the complete extension source (manifest.json, popup, options, content script, icons; no build step, no external calls)
• Install-and-User-Guide.pdf — step-by-step install + how to use every feature
• README-license.txt — single-buyer license and disclosures
• $19 — one-time download, yours to keep.

Key features

• Popup fee calculator → enter item price, shipping charged, item cost and shipping cost, pick a channel, and instantly see total fees, net proceeds, profit after costs, and margin %
• ON TARGET / BELOW TARGET flag → every estimate is flagged against the target margin you set
• On-page overlay → a small dismissible chip appears next to prices on listing pages, showing the estimated fee + net for your default channel; it never touches page layout, and one click dismisses it
• Customizable price detection → a selector list controls how FeeLens finds prices on pages
• Settings page → four channel fee presets (Etsy-style, eBay-style, Amazon-style, own-store); every percentage and fixed fee is editable and saved in your browser; set your default channel, target margin %, and toggle the overlay on or off
• Privacy as a feature → everything is computed locally; FeeLens makes no network requests of its own, sends no analytics, and transmits no browsing data anywhere (verified in QA: zero external network requests across all flows)
• QA-verified → 60/60 checks passed (manifest validation, 31 unit/cross-check fee-math tests, 15 end-to-end browser tests, docs and ZIP integrity)