Consignment sellers of fresh produce
You hold no inventory, so the day your supply price changes is the day your margin changes. We catch the window where the listing price stayed put and only the cost moved.
Supply price · market reference · settled fees, in one calculation
Know the day
your cost moved
SellerMaru joins three numbers that normally live apart: what your wholesaler charged you today, what your Coupang and SmartStore listings are still priced at, and the fees actually deducted at settlement. Each morning it picks out the products whose margin collapsed, and gives you the floor price below which the sale loses money. Market data is an input to that decision — it is never presented as the decision.
Get started free See how it works
Supplier channels connect only through credentials you delegate yourself. They are encrypted and belong to your account alone.
Underwater
신비복숭아 2kg 특품
₩5,900 → ₩6,400 +8.5%
Floor ₩7,120 · Listed ₩6,900
Near floor
애플수박 1통 (5kg 내외)
₩12,400 → ₩12,780 +3.1%
Floor ₩13,050 · Listed ₩13,900
Needs a look
대추방울토마토 1kg
Yesterday's value could not be read
Movement unknown — which is not the same as out of stock or unchanged
Who this is for
Built for three kinds of seller
Sellers running two or more wholesalers
See the same pack side by side across suppliers, priced as landed cost with the shipping terms folded in. Whether you may actually switch supplier is answered by checking the spec axes one at a time, and showing you which ones we checked.
Sellers who also run group buys and live commerce
Set your unit price against that day's supply cost and the wholesale market reference on one screen. The supplier's own raw wording sits beside our parse, so you never have to take a tidied-up number on faith.
What changes
Every morning, checking becomes a conclusion
Before · what you checked by hand
- Open each wholesaler's site in turn to find today's price.
- Rely on memory, or a spreadsheet you kept, for what yesterday cost.
- Guess at margin by adding rough fees and shipping in your head.
- Discover the per-order loss only after the coupon is already live.
- Open a public price site separately and eyeball the comparison.
- Decide whether you can switch supplier from how similar the names look.
SellerMaru · the conclusion, waiting for you
- Today's price from every connected supplier, on one screen.
- Only the products that moved against yesterday, gathered together.
- The break-even floor, computed with your price, fees and shipping in it.
- The coupon-applied price as its own separate sentence — and no number at all when the terms are ambiguous.
- Wholesale market prices matched to the same pack spec before comparing.
- The spec axes we checked, printed beside the ones we could not.
Margin alert
Is a price rise quietly eating a product you are still selling?
We read your connected suppliers' prices daily and pull out only what changed against yesterday. Then we take your listing price, subtract the category commission, the shipping you absorb and a provision for loss, and compute the break-even floor — anything trading below it is marked underwater. The floor follows the terms you entered and the fees actually settled, and every value that went into it is expanded on screen.
- Underwater means one thing only: the listing price fell below the floor. A loss caused by a coupon is a separate sentence, carrying the coupon's own terms and expiry.
- Loss provision divides the cost by what remains, rather than multiplying it by a rate. Multiplying always under-states the real exposure.
- Stale, unread, failed and genuinely zero are four different states on the screen. Missing data never renders as fresh data.
| Supply price | ₩6,400 |
|---|---|
| Shipping | ₩3,000 |
| Category commission | 10.8% |
| Loss provision | 3.0% |
| Break-even floor | ₩10,640 |
| Currently listed at | ₩9,900 Underwater |
The commission and provision rates in this table are values you set, and the working is expandable on the real screen.
Market reference
At today's market, is this price actually expensive?
We compare your supply price against wholesale auction prices matched to the same pack spec. When the markets disagree about direction, we do not merge them into one sentence — we report each market separately. Averaging contradictory moves produces noise wearing the costume of evidence.
- Weekly trend direction was contested between markets, beyond ±2%, in 31.8% of series-weeks measured (measured in-house 2026-08-07; 36.3% on a monthly basis).
- Auction prices and survey prices are different measurements. Auction leads the comparison and survey corroborates it. Neither is blended into the other to produce a single figure.
- You choose which markets are in scope. If nothing in that scope matches the product, we say so plainly rather than quietly widening the search until something matches.
- 가락 +4.2%
- 강서 −1.8%
- 대구 +5.0%
Direction contested — not merged into one claim
A single trend sentence is issued only when every market in scope moved the same way.
Supplier compare
Same product — so which supplier is actually cheaper?
We put the same pack side by side across suppliers and compare on landed cost, with each supplier's shipping terms resolved into the figure. The cheapest on unit price and the cheapest once shipping lands are frequently not the same supplier. And every comparison we print carries its denominator.
- "Cheapest of the 4 you selected" — never "cheapest available". What the claim was computed over is always stated beside it.
- Whether you may switch is decided by checking cultivar, origin, grade, pack count, weight and shipping terms individually. A shared name is not evidence of a shared spec.
- Axes we checked print the parsed figure itself; axes we could not check say so. Neither is collapsed into the single word "matches".
| Supplier | Unit price | Shipping | Landed cost | Order cutoff |
|---|---|---|---|---|
| 데일리푸드 cheapest of the 4 selected | ₩5,900 | included | ₩5,900 | 09:30 |
| 강원농산 | ₩5,600 | ₩3,000 | ₩8,600 | 15:00 |
| 산지직송상회 | ₩5,900 | ₩2,500 | ₩8,400 | 11:00 |
| 한결유통 out of stock | ₩5,750 | ₩3,000 | — | 10:00 |
Axes checked 포장 중량 2,000g 일치 · 입수 1개 일치
Axes not checked cultivar · origin · grade — could not be read from the suppliers' own wording
The lowest figure in this table was computed over the four suppliers you selected, and nothing else.
Features
What you actually use every day
Supplier connections
We connect the way each supplier opens. An API where one exists; otherwise your own browser reads the page, or you upload the price file they already send you. Which route a figure arrived by is printed on the screen.
APIBrowser readFile upload
Today's alert
What moved, what broke the floor, and what we failed to read, separated and gathered into one morning screen. You set the thresholds yourself.
Price movementUnderwaterThresholds
Listing matching
Link the products you list on Coupang and SmartStore to the supplier products behind them. Automatic suggestions are only ever suggestions — confirming and unlinking are always human acts.
UnmatchedMatchedEnded
Floor price
Break-even selling price with category commission, shipping and loss provision folded in. One implementation of the formula, expandable on screen.
Fee setupBreak-evenWorking shown
Coupon-applied price
The listed price and the coupon-applied price sit at equal weight, side by side. Where membership tiers or quantity terms make the figure unknowable, we print the reason instead of a number.
Coupon termsApplied priceWithheld
Purchase orders
Registration and payment are separate calls, each with its own human approval. You only move to payment after seeing the amount the supplier's own system returned.
RegisterConfirm amountApprove payment
Browser extension
Do you know when you lost the Item Winner slot?
With the extension installed, the product pages you are already looking at are read and recorded — the winning price and the other sellers, as the page states them. No server logs in on your behalf; we only read what your own browser is already showing you.
- Pages we failed to read are collected under their own "read failed" heading. A broken read never becomes a wave of reported losses.
- A rank's denominator is the number of result rows actually read. Coupang's search is infinite scroll with no total, so "not in the 60 we read" and "not listed" are written as different sentences.
- The other-sellers list includes the buy-box holder. Competitors are counted by identity rather than position, so you are never counted as your own rival.
The extension is still in preparation. Supply prices, floors and market comparison all work from the web app alone.
Observed winning price
₩12,900
다른 판매자
Your listing
₩13,500
not the winner
Your floor
₩12,100
We do not suggest a price at which you would retake the slot. The two honest numbers are above; the decision between them is yours.
1 read failed
The page structure changed and could not be read — this is not a lost slot
Rank denominator: 60 result rows read (not a total result count)
Principles
What we have decided not to build
What a tool refuses to do defines it as much as what it ships. These four are places we have decided not to trade honesty for convenience.
No retake price
We will not produce a number claiming to be the price at which you would win the Item Winner slot back. The two honest figures are the observed winning price and your own floor; where you land between them is a business judgement. A plausible-looking modelled estimate is exactly the kind of number sellers stop trusting first.
No lowest price without its denominator
"Cheapest" only becomes a fact once you know what it was counted over. We always state whether it is the cheapest of the few you selected or of everything we hold. A comparison with its scope erased misleads more than it helps.
Unread is never reported as empty
Stale, unread, failed and genuinely zero are four distinct states. We do not build screens where missing data can look current, or where a failure can look like "none found".
No order without approval
A purchase order splits into registration and payment, and at each step a human approves against the actual amount the supplier returned. There will be no single button that orders and pays in one gesture.
Questions
Frequently asked
How are supplier credentials stored?
Credentials you delegate are encrypted and belong to your account alone. A channel is identified by the supplier's address and your ID there, and when you rotate a password we prove the new credential works before deleting the old one.
Can other sellers see my supply prices?
No. You see public rows plus your own, and there is no third state in between. Anything you add is private by default and is never shared with another tenant.
Do I need a Coupang or SmartStore account?
No. Connecting a supplier alone gets you price movement and supplier comparison. The floor price and the underwater verdict need your listing price and settlement terms, so connecting a marketplace sharpens both.
Our wholesaler isn't on your list.
If they open the way a supported adapter reads, connecting is a registration and nothing more. If not, you can still start by uploading the price file they already send you. Tell us who you buy from and we will tell you which of the two applies.
What does it cost?
Pricing is still being finalised, and will be published on this page with VAT treatment stated when it is. Early users are being onboarded individually — email us and we will walk you through it.
Where does the market data come from?
Publicly released wholesale auction prices and price survey data. They are different measurements, so we do not blend them; the auction figure anchors the comparison. Source, reference date, pack spec and freshness are shown alongside every figure.
Will SellerMaru place orders for me?
Not without your approval. Registration and payment are separate steps, and at each one you approve against the amount the supplier's own system returned. An order that is only registered stays freely cancellable until it is paid.
See how far your costs moved today —
tomorrow morning
Connect a single supplier and the movement and floor arrive from the next morning onward. Sign-up works in Korean and English.
Please note · SellerMaru is a tool that reads supply information and provides a basis for your decisions. It is not a party to the sale or brokerage of any goods. Trading terms, settlement, returns and claims are governed by your own contract with the supplier.