Built by running a real reselling business

Listed before you've found the next thing.

Photograph an item and it comes back identified, priced against real completed sales, and written up — a median of 19 seconds, measured across 1,046 single-item researches. Then it goes to every channel you sell on at once, instead of the same form three times.

Not open for signups yet. One operation runs on it today — 462 items, 136 sales, and every fix below found the expensive way.

Sold comps · PSA 10 rookie card 4 rejected
  • 2025 Topps #201 Rookie RC — PSA 10 Gem Mint$74.99
  • 2025 Topps #201 Rookie RC — near mint, ungraded✗ raw copy · query is PSA 10$12.50
  • 2025 Topps #201 RC PSA 10$69.95
  • 2025 Topps #201 base rookie card$3.99
  • 2025 Topps #201 Rookie — PSA 10$67.00
  • 2025 Topps #201 RC — lot of 4, ungraded✗ multi-card lot · cannot price one card$18.00
  • 2025 Topps #201 Rookie PSA 10 Gem Mint$71.00
  • Topps #201 rookie — raw, off-center$9.25
  • 2025 Topps #201 RC — PSA 10$69.95
Median comp
$69.95
5 graded sales kept
4 rejected

What those seconds are spent on. Blending graded and raw sales would have priced this card at $25.24 — a number at which neither version of it sells. Fast is only worth something if the answer is right. Listing titles here are representative; the figures are the ones production returned.

19smedian to identify and price an item
462items under management
397items listed on eBay
136shipping labels bought and printed

Not a demo dataset. These are the operating numbers of the reselling business the software runs, built and used daily between April and August 2026.

The job today

Twenty items from an estate sale, four problems on every one.

What is it worth?

Pricing means squinting at completed sales

And half of them are a different edition, generation, or condition of the same product. Price too high and it never sells. Too low and the margin is gone.

Listing

Serial when it should be parallel

Every marketplace has its own form, category tree, and required fields. Listing one item in three places is three times the work — so most sellers list in one and accept a smaller pool of buyers.

Inventory

Two channels, one physical item

The channels don't talk to each other. Selling the same unit twice costs a refund, a damaged account metric, and the customer.

Money

Revenue gets mistaken for earnings

Platform fees, shipping, and what you actually paid live in three different places — or nowhere at all. Most sellers cannot tell you their real profit.

One system, acquisition to accounted-for profit

Photograph it. The rest is handled.

BayBrain identifies the item, researches what it genuinely sells for, drafts the listing, publishes it to every channel you use, keeps stock synchronized so one unit cannot sell twice, buys and prints the label, and reports what you earned.

01Acquire
02Identify
03Price
04List everywhere
05Sell
06Ship
07Measure

Running in production

  • Identify and price from a photograph. Reads model numbers, set numbers, and grading labels off the item itself, then returns a price with a confidence level attached.
  • Resell Score. Every researched item gets a 0–100 score with plain-English reasons, so you know whether to buy another one.
  • eBay, end to end. Listing, repricing, offers to watchers, promoted listings, order import, scheduled publishing, and traffic analytics.
  • Mercari. Publishing, repricing, listing reconciliation, and automatic sale detection.
  • Real profit. Per-item cost, platform fees, and shipping produce true margin and ROI — including cost split across a bought lot.
  • Ship and print. Buyer addresses resolved automatically, carrier rates compared, label bought and sent to a thermal printer.
  • Never oversell. When a unit sells or hits zero, it is made unbuyable everywhere else automatically — and retries through platform outages.

Built and tested, not switched on

  • Shopify — and through it, Facebook and Instagram Shops. Awaiting a connected store.
  • Amazon — seller-fulfilled offers against existing catalogue listings. Awaiting an account connection.
  • eBay auctions — starting bid, duration, reserve, optional Buy It Now, for lots where the market should set the price.
  • Mercari native promotion — promotion, offers to likers, and time-limited sales, each held to the cadence Mercari rewards.
  • Sourcing scans — saved searches that rank underpriced stock by projected return.
  • Social publishing — captions and branded graphics generated from listing photos, posted on a schedule.

These are listed separately on purpose. They are engineered and covered by tests, but they have not carried real money yet, and saying otherwise would be the same kind of guess this product exists to avoid.

Found in production, against real inventory

Every one of these was a price someone would have accepted.

Each was diagnosed, corrected, and locked in with a regression test so it cannot come back. This is the part that cannot be designed in advance — only discovered by running a real business on the software.

ItemWhat it would have priced atCorrected
Collectible figure setNo usable comparable sales — priced off other sellers' asking prices$76.60 · 20 verified sales
Graded trading card$25.24 — graded and ungraded sales blended together$69.95
Graded trading card$21.00 from a single unrelated sale$69.99 · 19 verified sales
Four-item electronics lot$17.95, with only one of the four items priced at all$145.08 · all four, ~25s
Collectible action figure$69.99 from one incorrect match$54.00 · 4 verified matches
Die-cast collectibleNo usable match found$30.99 · 4 exact matches
Raw comic bookPriced against professionally graded copies$459.50 · raw copies only

Why this is hard

Anyone can look up what something sold for.

Identity comes before price

The difficulty was never the lookup. It is knowing which of those sales is the same product as the thing in your hand. BayBrain treats that as the first question, not an afterthought.

Photos are evidence, except when they aren't

Visual checks confirm a comparable sale really shows your product. Just as important is knowing the categories where photos actively mislead — a slabbed card, a stick of RAM — and not trusting the picture there.

It is allowed to say no

Where the evidence is thin or contradictory, you get "not enough evidence" instead of a plausible-looking number. A wrong price you trust is worse than no price at all.

Early access

Tell us what you sell.

BayBrain runs one operation today. Opening it to other sellers is the next piece of work, and the people on this list get first access and set the priorities. No newsletter, no drip sequence — one email when there is something to use.

We store your email to tell you when access opens. Nothing else, and no sharing.