Answer in brief
You have decided to sell but have not shipped yet. Six blocks close before the first delivery: documents, barcodes and article numbers, the category and its attributes, the listing, packaging and price. Here is each one, and which edits stay cheap.
The short answer: six blocks to close before you ship
The short answer is that six blocks have to be closed before a first shipment leaves the building: product documents, barcodes and your own article numbers, the category together with its attributes, the listing itself, packaging that matches warehouse rules, and a price built from real costs. Everything below explains why that order is the one that works.
The order is not arbitrary. Documents decide whether the product can be listed at all. The barcode decides how a warehouse recognises it. The category decides which fields you are obliged to fill in. Only after those three does it make any sense to write listing copy or plan a photo session.
First-time sellers often work backwards. They build a good-looking listing, then discover the category was the wrong one and its mandatory attributes are different. The copy gets rewritten, the photographs get reshot, and part of the batch is already sitting in a warehouse in packaging that does not suit it.
What follows takes the blocks one at a time and marks which of them stay a cheap edit on any given day, and which turn into an expensive rebuild the moment the first delivery is accepted at goods-in.
Documents: what proves you are allowed to sell this
The first question is not about sales, it is about admission: do you have the right to sell this product, and can you prove it with paperwork when the platform or an inspector asks for it. The product category decides what that pack contains, and it differs for clothing, cosmetics, electronics and children's goods.
Look at three things. Evidence of conformity for the product itself. Permission to use the brand if the label is not yours. And a supply chain you can show, meaning some record of where the batch actually came from. Not every product needs a certificate, but you establish that before you buy stock rather than after.
Brand rights deserve their own line. Selling somebody else's label calls for written confirmation from the rights holder or an authorised distributor. Platforms take listings down on a brand complaint quickly, and getting them back takes considerably longer than collecting the paperwork in advance would have taken.
Keep everything in one folder with readable file names and expiry dates written into the names themselves. It is dull work, and it is precisely what turns a future platform request into a five-minute task rather than a week with your sales switched off.
Barcodes and article numbers: the identity layer
A warehouse has no eyes. It recognises a box and a unit by a code, which is why you decide before shipping which code you are using and print it so that a scanner reads it on the first pass rather than the fourth.
There are two routes. One is a global identifier, a GTIN issued through GS1 and formally assigned to your company; in EAN-13 form that is thirteen digits. The other is an internal code the platform generates for you. Which route is acceptable is set out in each platform's own documentation, and you check it before labels go to print.
Alongside that, define your own article numbers. An article number is your key to the product in your own records, and it has to survive a change of platform. A readable scheme along the lines of category-model-colour-size stays usable by a human when the catalogue reaches three hundred lines.
Test the print physically: contrast, size, the quiet zone around the code, and the label stock itself. A thermal label that has faded after a month in storage costs exactly as much as a lost unit, and you find that out at goods-in rather than at your own desk.
Category: the decision that is expensive to reverse
Category is the most expensive decision on this list. It sets the commission, the set of mandatory attributes, the packaging requirements, and the filters in which a buyer can encounter you at all. Getting it wrong is not a cosmetic problem, it is a structural one.
Choose by where the buyer looks, not by what you call the product inside your own company. Walk the path yourself: type the query, see which filters the platform offers, and note which branch of the tree holds the products that genuinely compete with yours.
Changing category after the first delivery rarely happens cleanly. Part of the accumulated performance history and reviews may not travel with the listing, and the listing itself starts again at the back of the relevance queue. That is not a prohibition, it is a reason to spend an hour before shipping instead of a quarter afterwards.
When two branches look equally plausible, let the filters decide it. The better branch is the one whose filters describe your product precisely and let a buyer strip out everything else and keep you in the results.
Attributes: the table that decides who filters you out
Attributes are not supplementary information, they are the filtering mechanism. A buyer ticks size, colour and composition, and the platform removes everyone whose field is empty. An unfilled attribute is not a gap in the description, it is an exclusion from the results under that filter.
Fill them from the object, not from the marketing plan. Composition, weight, packed dimensions, country of manufacture, the size grid: all of it gets checked against reality at goods-in and again in the reviews. A dimension that is wrong changes your logistics tariff, and a composition that is wrong comes back as a claim.
Build the attribute table before you create the first listing. Past ten products, filling fields one card at a time is a reliable source of typos, while a table gives you one source of truth and lets you upload the whole set in a single pass.
Measure weight and dimensions in the packaging the product will actually travel in. Take them from scales and a tape measure rather than the manufacturer's spec sheet, because you are charged for the box and not for the item inside it.
The listing: title, description and what search can read
A listing title does two jobs: match the query and stay readable. A working formula is product type, brand, the key distinguishing feature, the use case, the variant. Stacking synonyms end to end helps search less than sellers expect, and it costs you the human reader outright.
Write the description for a person who is already hesitating. Answer what the photographs cannot show: how it fits, what it is made of, what comes in the box, how it is cared for, and who it is not for. That last point reduces returns more reliably than any adjective in the paragraph above it.
Do not hide anything important inside an image. Text baked into a picture is not read by the platform's search, not read by a screen reader, and not read by a buyer on a small phone screen. A size chart has to exist as text and as attribute fields, not only as attractive artwork.
Keep one document holding the copy for every listing. When you work out a month later which title formula performs, the edit is not to one card but to the whole set, and nobody reconstructs a set like that from memory.
Photography: shoot while the stock is still with you
Photograph before you ship, because after shipping you no longer have the product in your hands. This is a common reason a listing goes live with three frames instead of ten and then stays that way for several months.
The minimum set is the whole product on a neutral ground, a detail frame for material and stitching, a scale reference beside a familiar object, a shot in use, and one of everything included. The first frame is the only one a buyer sees in the results, so it is chosen deliberately rather than by upload order.
Treat fully model-generated images with care, for two separate reasons. The practical one is that a buyer compares the picture with the parcel and files a return. The legal one is that a fully generated image may leave no exclusive copyright with anyone, which means you would have nothing to enforce if a competitor reused it.
Shoot more frames than you think you need and keep the originals at full resolution. Cropping and adapting them for another platform is easy later; going back for one missing angle once the batch sits in a warehouse is not possible at all.
Packaging and labelling for warehouse rules
On a marketplace, packaging is not about unboxing theatre. It is about whether the product arrives intact and whether the warehouse accepts it in the first place. Requirements for labelling, inserts and packaging type are set by the platform, and they differ from one category to the next.
Check three things in advance: whether the packaging survives transport and repeat handling, whether the label is readable on the face of the box that actually gets scanned, and whether your product needs special treatment as fragile, liquid, scented or storage-restricted goods.
Packed dimensions are money. One extra centimetre can push a box into the next tariff band, and across a whole batch that is a visible sum. Measure the finished package rather than the item, and compare the result against the platform's own tariff grid before you order boxes.
Assemble one complete box and send it to yourself. Half an hour of that shows you more than reading the regulations does: what creases, what stops being readable, and what you forgot to put in.
Price and the economics of the first batch
Price is calculated before shipping because changing it afterwards is not a free move. From the retail price subtract the category commission, logistics, storage, payment processing, return handling and the cost of the goods themselves. Whatever survives that subtraction is your margin.
Build returns into the model from the start. In clothing and footwear the return share is structurally higher than in products bought without fitting, simply because size is verified at home. That is not a statistic, it is the mechanics of the category, and it belongs in the calculation.
Treat the first batch as an experiment with a budget. Its job is not profit, it is data: which sizes and colours move, what comes back, what the reviews say about it. A first shipment that is too large buys exactly the same data at an inflated price.
Cutting the price sharply after launch costs money too. It breaks the model you have just built and teaches buyers to wait for the discount instead. Start at an honest price and decide in advance how far down it is allowed to go.
What becomes expensive after the first delivery
It helps to sort decisions into cheap and expensive before you make any of them. Cheap ones are the description copy, the order of the photographs and a good share of the attributes: those can be edited on any day with no consequence for the listing's history.
Expensive ones are the category, the barcode and article scheme, the composition of a bundle, and packaging sized to a tariff band. All of that is already printed on labels, built into boxes and recorded at goods-in, so a change drags physical repacking of the batch behind it.
The listing as a unit is another expensive one. Merging or splitting listings by variant after reviews have accumulated almost always loses part of what accumulated, so the question of what counts as one product gets settled before anything is shipped.
A simple rule: if fixing it requires physical access to the batch, it belongs in the expensive column. Decisions in that column get checked twice and written down before the first label is ever printed.
Structured data and accessibility: the half that lives off-platform
A marketplace is not the only place your product lives. Your own site, the catalogue that search engines read and any feed you send to an aggregator all use the same data, and preparing it once is cheaper than assembling it from scratch three times.
On your own site a product is described with Schema.org Product markup, which carries fields for sku, gtin, brand, offers and reviews. The article numbers and codes you defined earlier move into that markup without rework, which is the exact moment the dull table starts paying for itself.
Accessibility is not a separate project, it is a property of the same content. WCAG 2.2 asks for text alternatives for images and a contrast ratio of at least 4.5:1 for normal text, and it adds a minimum target size of 24 by 24 pixels for interactive controls. The same work makes the page usable on a phone.
One point about formats. Search engines do extract and index the text inside PDFs, so a specification sheet or size chart published as a PDF on your site can be found through search. The same text baked into an image is findable nowhere at all.
The first two weeks, and what to hand to someone else
A first shipment is not a sales launch, it is the start of data collection. In the first two weeks you watch four numbers: impressions, clicks into the listing, conversion to order, and the stated reasons for returns. Each one points back at a specific block in this checklist.
Few impressions is a question about category and attributes. Impressions without clicks is a question about the first frame and the title. Clicks without orders is a question about price, description and reviews. Returns are a question about dimensions and about how honest the photographs were.
What you hand to someone else should depend on where you have no time, not on what feels difficult. Reading demand and the structure of a category is a couple of days of work, and it is sensible to buy that before shipping, while the decisions are still cheap to change.
Rewriting listings, marking up your own site and running a continuous cycle of revisions are jobs of very different sizes, and they sit in separate packages for that reason. The terms, timelines and limits of each are set out on the service page.
Practical checklist
- Collect product documents and brand permissions in one folder before you buy the batch.
- Fix your article-number scheme and the source of your barcodes before labels go to print.
- Walk the buyer's path and pick the category by its filters, not by your internal product name.
- Fill the attribute table completely, including weight and dimensions in real transport packaging.
- Shoot the full frame set and keep the originals while the batch is still in your hands.
- Calculate margin with commission, logistics, storage and returns before the first box ships.
Questions and answers
I have already bought stock but have not shipped anything. Where do I start?
With documents and category. Both can invalidate work done later: without paperwork a listing can be taken down, and the wrong category changes the mandatory attributes and the packaging requirements. Copy and photography come after those two.
What does it cost to check demand and category before shipping?
The Demand Audit is $50 and takes 1-2 working days, including one round of revisions on the findings document. Access to your seller account is not included in that package.
Do I need a GTIN, or is a platform-generated code enough?
It depends on the platform and the category. A GTIN is issued through GS1 and assigned to your company, while an internal code belongs to the platform. Check the requirement in the platform's own documentation before labels go to print, not after.
Where should the size chart live?
In the listing text and in the attribute fields, not only in an image. Text inside a picture is read neither by search nor by screen readers. On your own site the same chart can also be published as a PDF, since search engines index the text inside PDF files.
Who writes the listings when there are a lot of products?
The Marketplace + SEO System covers that at $110 over 3-5 working days, with 2 rounds of revisions on listings and copy. Photography and paid placement are not part of that package.