Profitlee's answer:

Next.js 16 (App Router) and React 19 with TypeScript, styled with Tailwind CSS v4. Postgres (Neon serverless) via Drizzle ORM, authentication with Auth.js (NextAuth v5), billing through Lemon Squeezy, transactional email via Resend + React Email, PDF export with react-pdf, and internationalization via next-intl. Tested with Vitest and deployed on Vercel.

Profitlee's answer:

It started as the messy spreadsheet I kept rebuilding for every product I evaluated. "Sale price minus product cost" was never the real margin — referral fees, the FBA fulfillment tier, the fuel surcharge, VAT on EU marketplaces, ad spend, and returns all quietly ate into it, and I usually only saw the true number after the inventory had already landed. So I turned the spreadsheet into a proper tool with accurate, country-specific fee logic and made it auditable against each marketplace's official schedule. Profitlee is the result — an independent, solo-built calculator (not affiliated with Amazon or TikTok).

Profitlee's answer:

Accuracy you can verify. Profitlee breaks the full cost stack out line by line and its outputs have been cross-checked against Helium 10 and Amazon's live fees down to the cent. It's multi-marketplace (US/DE/JP + TikTok Shop) and multi-mode (FBA, FBM, Fulfilled-by-TikTok, self-fulfilled) in one tool, the core calculator is free to use with no signup, and a per-unit calculation instantly scales into a monthly revenue/gross/net P&L. Pro stays affordable at $9.99/mo (or $99/yr) and adds saved scenarios, history, PDF export, and shareable links.

Profitlee's answer:

Amazon FBA/FBM and TikTok Shop sellers — from first-time and side-hustle sellers validating a product before they source inventory, to established sellers and agencies pricing new SKUs across the US, German, and Japanese marketplaces. Anyone who needs to know their true net margin before committing to inventory.

Profitlee's answer:

Profitlee is a country-accurate profit calculator: instead of one generic "fee" estimate, it uses real, separately-maintained 2026 fee tables for Amazon US, Germany, and Japan plus TikTok Shop — including size tiers, referral categories, the 3.5% fuel surcharge, inbound placement, and storage. It's VAT-aware on the EU/JP marketplaces and models the costs most calculators skip: ad spend as ACOS or TACOS, and return losses (refund administration fee + unsellable write-offs), not just marketplace fees. Every fee links back to the marketplace's own published schedule, so any number is auditable.

Profitlee's answer:

Profitlee is newly launched and used by independent Amazon FBA and TikTok Shop sellers across the US, EU, and Japan marketplaces.