StackBuddy — by SellerStack3P

Auto-import Amazon FBA fees and margin data into SellerStack3P. Built for Amazon sellers, by an Amazon seller.

StackBuddy is the companion Chrome extension for SellerStack3P, the Amazon FBA margin tracking and cash back stacking dashboard. WHAT IT DOES When you're on Amazon's FBA Revenue Calculator (sellercentral.amazon.com), StackBuddy reads the official fee breakdown — item price, FBA fulfillment fee, referral fee, and monthly storage fee — and lets you push that data into your SellerStack3P dashboard with one click. No copy-paste. No manual entry. No outdated fees when Amazon raises them. TWO MAIN WORKFLOWS Both workflows use the in-app magnifying glass button to open Amazon's authenticated FBA Calculator — this requires an active Amazon Seller Central account, which all Amazon FBA sellers have. The extension also works on Amazon's public guest calculator (sellercentral.amazon.com/revcalpublic) if you navigate to it directly. 1. Sync fees for ASINs you already own Click the magnifying glass next to any ASIN in your SellerStack3P dashboard. Amazon's FBA Calculator opens with that ASIN pre-loaded. Search, then click "Send to SellerStack3P" on the StackBuddy banner. Your fee fields update automatically. Storage fee — the one fee Amazon's SP-API doesn't expose — is also captured. 2. Research new ASINs before buying Type any ASIN into the "Research an ASIN" card in SellerStack3P (even ASINs you don't own). Click the magnifying glass. Amazon's calculator opens, StackBuddy reads the fees, and the research card auto-populates with item price and all four Amazon fees. See the true margin math before you commit to sourcing the product. REQUIRES SELLERSTACK3P ACCOUNT StackBuddy is a companion to SellerStack3P (https://sellerstack3p.com) — a separate web application that handles cash back tracking, margin calculation, inventory & reorder tracking, and supplier analytics for Amazon FBA sellers. You'll need an active SellerStack3P account (14-day free trial available) to use this extension. The extension popup walks you through connecting it to your account when you install. WHERE IT RUNS StackBuddy activates on three Amazon Seller Central paths and one SellerStack3P path: - The authenticated FBA Revenue Calculator (sellercentral.amazon.com/revcal*) - The guest FBA Revenue Calculator (sellercentral.amazon.com/revcalpublic*) - The legacy FBA Calculator path (sellercentral.amazon.com/hz/fba/profitabilitycalculator/*) - The SellerStack3P connect page (sellerstack3p.com/extension/*) It does not run on any other Amazon page, does not access your Seller Central account data, and does not collect or transmit any browsing data. UPSTREAM ERROR HANDLING Amazon's Revenue Calculator occasionally returns errors (rate limiting, temporary outages, server-side issues). When that happens, StackBuddy displays a clear red banner explaining the situation with a "Reload page" button. No silent failures, no hanging spinners — you always know whether the sync is in progress, succeeded, or hit an Amazon-side issue. PRIVACY & DATA - StackBuddy reads the public fee breakdown shown on Amazon's calculator page — the same data visible to you on screen. - Fee data is transmitted to SellerStack3P's API only when you click "Send to SellerStack3P." - The extension stores a session token in chrome.storage.local to identify you to your SellerStack3P account. No other data is stored or shared. - See the full privacy policy at https://sellerstack3p.com/privacy OPEN SOURCE & TRANSPARENT StackBuddy's code is straightforward and inspectable. The extension does not minify or obfuscate its code — every content script, background script, and popup script is human-readable in the unpacked extension. Full source available on request.