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The vendor-neutral reference for starting, running, optimizing, and scaling an ecommerce and third-party-marketplace business — with current, sourced, dated answers instead of another platform's sales pitch.
Marketplace hubs
Compare all →Amazon
The broadest buyer base of any marketplace, and the most operationally demanding to run well.
Walmart Marketplace
A strong second or third marketplace, with lower competition than Amazon in many categories and a reviewed (not instant) approval process.
eBay
The best fit for resale, collectibles, refurbished goods, and auction-format sales.
Etsy
Handmade goods, vintage (20+ years), and craft supplies — a genuinely restrictive category policy relative to general marketplaces.
TikTok Shop
Social- and video-first commerce — the newest major marketplace here, and the one whose terms move fastest.
Target Plus
Invite-only. There is no public self-serve application — and this hub says so plainly.
Temu
The largest low-price cross-border marketplace by traffic, now building a parallel local-fulfillment model — with fee terms that, unusually for a hub this size, aren't published anywhere official.
Shein Marketplace
Shein's third-party seller program, distinct from its original supplier-manufacturer model — with eligibility and fee reporting that varies noticeably between sources.
Popular tools
All tools →Marketplace Fee Calculator
See what a marketplace actually takes from a sale — referral fee, per-order fee, fulfillment, and estimated net proceeds — before you commit to a price.
Product Profitability Calculator
Model true per-unit and per-order profitability for a SKU, including COGS, fees, ad spend, and returns.
Safety Stock & Reorder Point Calculator
Calculate the safety stock and reorder point that protects you from stockouts without overstocking.
Beginner's Ecommerce Unit Economics Calculator
A simplified first-product profitability check for sellers who haven't launched yet.