# Seller Profit Doctor > Seller Profit Doctor shows online sellers on Etsy, Shopify and Amazon where their shop's money goes, and how to keep more of it. Every loss it finds comes with its fix and what the fix is worth in the seller's own dollars, at their numbers, if orders hold. The math is fixed formulas on each platform's published fees. No AI computes a number. Every result says which rules it used, the date they were checked, and links to the sources. Amazon's fulfillment, storage and returns fees sit behind the Seller Central login, so those figures come from third-party rate cards and are always marked as estimates. Etsy, Shopify and Amazon are trademarks of their owners. Seller Profit Doctor is independent and isn't affiliated with, endorsed or sponsored by them. ## Free MCP server for AI agents - Endpoint: https://sellerprofitdoctor.com/api/mcp - Transport: streamable HTTP. Send JSON-RPC by POST. Both the 2025 protocol (initialize first) and the 2026-07-28 protocol work. - Cost: free. No sign-in and no key. - Privacy: the tools take numbers and fixed choices only, never names, emails or shop links. Nothing is stored. The logs keep only each call's tool name and how long it took. - Limits: up to 60 calls a minute from one address, and a request body of 64 KB at most. - Platforms: Etsy, Shopify and Amazon (`platform_supported: ["etsy", "shopify", "amazon"]`). Any other platform gets one fixed "unknown platform" error. - Status: https://sellerprofitdoctor.com/api/mcp/status (JSON). Every 10 minutes the site runs five real steps against this server (the handshake, the tool list, the check-up, a calculator, the rates) and keeps only pass or fail, each step's time and the server's version; the uptime for 24 hours, 7 days and 30 days is there too. - For people: https://sellerprofitdoctor.com/ai-assistants (how to connect from Claude, ChatGPT and other MCP clients, and the live status). ## Tools - `sellerprofit_checkup`: the full check-up for an Etsy shop, a Shopify store or an Amazon seller. Set `platform` (`etsy` is the default) and pass that platform's answers. Etsy: orders, item price, materials, shipping, label, the $10,000 question, Etsy Ads. Shopify: orders, order value, product cost, shipping, label, plan and billing, how cards are paid, ads. Amazon: units, price, landed cost, category, FBA or FBM, plan, the FBA fee or the packed size and weight, Sponsored Products. Bands and "not sure" are fine. Returns the grade, what each order (on Amazon, each unit) and each month keep, the top 3 losses with their fixes and dollar values, the defaults it used, and the dated rates. - `sellerprofit_etsy_fees`: Etsy's fees on one sale, line by line. Covers listing, transaction, processing (also on sales tax), currency conversion, and Offsite Ads at 12% or 15% with the $100 cap. - `sellerprofit_offsite_ads`: what Etsy's Offsite Ads cost at the shop's share of sales, per order and per month, the item price that covers the fee, and when opting out is possible. - `sellerprofit_shipping_gap`: what the label and packaging cost an Etsy shop beyond what the buyer pays, per order and per month. Also the item price that covers it while keeping shipping under Etsy's $6 search line, and what calculated shipping would keep. - `sellerprofit_ads_breakeven`: the ROAS at which Etsy Ads pay for themselves, the most an ad can cost per sale, and, given the shop's ROAS, what the ads gain or lose a month. - `sellerprofit_price_for_margin`: the Etsy item price at which one order keeps a target profit, in dollars or as a share of the order, after Etsy's fees, Offsite Ads, ads and costs. Also the break-even price. - `sellerprofit_shopify_plan_fit`: which Shopify plan (Basic, Grow, Advanced) costs least at a store's card sales, the sales above which each move up pays for itself on monthly and yearly billing, and what yearly billing takes off the price. - `sellerprofit_amazon_fees`: Amazon's fees on one unit at a price. The referral fee and the media closing fee are official. The FBA fee is an estimate from third-party 2026 rate cards, with the 3.5% fuel and logistics surcharge and the peak-season fee from October 15 to January 14. Also lists the price lines where a fee steps; a line whose reading Amazon doesn't confirm is marked unverified. - `sellerprofit_rates`: one platform's fee table (`platform`: etsy, shopify or amazon). Each fee comes with its value, a plain label, its source link, the date it was checked, whether it's official or a third-party estimate, and both values where sources disagree. Money is in US dollars. Shares are fractions, so 0.1 means 10%. ## Paid reports for AI agents - Endpoint: https://sellerprofitdoctor.com/api/mcp/agent (a separate server; the free one never takes payment). - `sellerprofit_buy_report`: the profit report ($19.99) or the full audit ($29.99), the website's prices, paid once. Send `tier` (`report` or `audit`), `answers` (the same object `sellerprofit_checkup` takes) and the seller's `email`. It returns a payment link and the price, and charges nothing itself. Run the free check-up first and ask the seller before paying. - Paying: request the link with a wallet that pays with Stripe's machine payments (MPP). It answers HTTP 402 with the price; pay and request it again. The answer to that paying request carries the report's link, which is also emailed to the seller; it isn't given again after that, so keep it for the seller. A person can open the same link in a browser and pay on the website instead. Paying or asking again never charges twice. If a payment's answer says it didn't go through but a charge appears anyway, it's settled within the hour: the report is delivered for it, or it's refunded in full. - `sellerprofit_report_status`: where a purchase stands: pending (with its payment link), paid, delivered (the report's link went to the seller's email), refunded or disputed. It never gives the report's link itself. - Sold by Gomorra Labs LLC; refunds for any reason within 14 days. A purchase keeps the answer codes and the email only. ## The grade - The grade is a word: Healthy, Good, with room to improve, Watch, Needs work, or Losing money. `grade.level` puts it in order, from 1 (Healthy) to 5 (Losing money). There are no letter grades. - With too few answers there's no grade yet: the word is "Not enough answers yet", `level` is null, and `grade.missing` lists the answers to ask for. Losses found still show. ## How to word the results - Say "at your numbers" and "if orders hold". A fix's dollar value is an estimate from the seller's own figures, never a promise. - When a result lists defaults (`isDefault: true`), tell the seller and ask for their real number. - When a figure has `estimate: true` (Amazon's fulfillment, storage, returns and peak fees), say "about" and "estimated", keep it apart from the loss total, and point the seller to Fee Preview in Seller Central. Passing their real FBA fee as `fbaFee` makes it their own number. - Cite the rules with the date and the source links each result carries. ## Examples "My Etsy shop gets about 100 orders a month. I sell a $30 item, materials are $8, buyers pay $5 shipping, the label costs $7, I've passed $10,000, and I spend about $10 a day on Etsy Ads at a ROAS of 1.5. Where is my money going?" The check-up's grade is Watch. About $446 a month is lost: a $300 shipping gap, $104.31 of Etsy Ads that don't pay back, and $42 of Offsite Ads not priced in. Each comes with its fix. "My Shopify store on Grow, paid monthly, does about 200 orders of $35 plus $5 shipping. Products cost $12, labels $7, and I spend about $2,000 a month on ads at a ROAS of about 2." The grade is Good, with room to improve. About $498 a month is lost: a $400 shipping gap, $50 from a plan bigger than the sales need (Basic costs less below about $33,000 a month in card sales), and $38 of ads below break-even. "I sell a $29.99 kitchen item on Amazon through FBA, about 1,000 units a month, $6.90 landed, packed 9 × 6 × 3.5 inches at 22 oz, $5,500 a month on Sponsored Products at 55% ACoS, and 10% come back." The grade is Good, with room to improve. Nothing is lost on Amazon's official fees, and about $1,892 a month is estimated from third-party fee rates: about $1,502 of Sponsored Products above break-even ACoS, and about $200 of returns over the category's line.