Last updated: Rules, fees and platform policies change. This guide is reviewed and kept current.
In marketplace operations, the mistakes you cannot undo are mostly made at the moment the product is first created. A wrong price gets corrected and a wrong image gets replaced; but a product opened and approved under the wrong barcode can no longer be fixed, in Trendyol’s own words: barcodes cannot be updated for approved products, and if you want to change one you have to create a new product with the correct barcode.
Knowing rules like that in advance costs many times less than cleaning up afterwards. Below I work through the points of no return in catalogue setup, the official factors that determine the buybox, and the technical limits of stock synchronisation. The figures are from the platforms’ own documentation as of August 2026; the one due to change in the near term is flagged separately at the end.
A note for international readers: this is written for sellers on Trendyol, Hepsiburada and Amazon.com.tr — Turkey’s main marketplaces. The mechanics are recognisable from any large marketplace, but the specific limits and the Turkish trademark office (TURKPATENT) references are Turkey-specific.
Catalogue setup: which decision cannot be undone?
Most errors are made at setup and only surface months later as lost revenue.
- BarcodeThe most expensive first decision; not correctable after approval
- Variant structureSlicer versus varianter, and the 100-variant limit
- Content and image rulesPrevents the rejection and relisting loop from the start
- BuyboxSeparate the documented factors from the folklore
- Stock synchronisationAPI limits and latency, including the 14 September 2026 change
Barcodes: the most expensive first decision
A barcode is mandatory at Trendyol — you cannot create products without one, and the system does not generate one for you. The technical limits:
- 1–50 characters. Forbidden special characters: ? / & % + ^ ‘ * _
- Spaces are collapsed. Spaces inside a barcode are stripped by the system, and you have to send your stock and price updates in the collapsed form. That invisible trailing space copied out of Excel is the single most common cause of “product not found” errors in integrations.
- For restricted brands only a global barcode (EAN/UPC/GTIN) is accepted; a code you generated yourself is rejected.
- There is a contradiction between the API documentation and the seller information centre on the character rule (one gives a forbidden-character list, the other says “only period, hyphen and underscore”). In a situation like that, follow the more restrictive one — using only letters, digits and hyphens passes both documents.
There are two further behavioural rules, and both are strategic.
Your barcode is public. Trendyol’s FAQ is explicit: can other sellers sell a product I added with my own barcode? Yes. Through the add-from-catalogue feature, others can be listed on the product page you created. So when you build the product page and write its content, the possibility of sharing that traffic with competitors exists from the start. That turns trademark registration and buybox protection from a technical question into a commercial one.
A duplicated product counts as a violation. When you get a “barcode already registered” error, the right reflex is not to open a new product under a different barcode — that is a 2-point violation and means the listing gets closed. The correct move is to join the existing product via “Add from Trendyol Catalogue”.
The uniqueness rule
Trendyol’s catalogue uniqueness definition looks at this combination: category + model code + brand + colour (or an equivalent distinguishing attribute) + the variant-defining attribute (size). No two barcodes can share all five. In the rejection message the barcode you collided with is reported as the “Reference Barcode” — do not throw that away, it tells you whose listing you landed on.
Variant structure: slicer versus varianter
Variants are handled through productMainId. On records sharing the same main product code, every field other than attributes must be identical — if one differs, you get a rejection.
There are two different variant types, and mixing them up breaks your product page structure:
- Slicer (colour, memory size and the like): shows the product on separate pages. A category can have more than one slicer.
- Varianter (size and the like): appears as an option on a single page. At most one varianter per category.
And a quiet limit: at most 100 variants per product. But that limit is calculated on the total of the variants already in the catalogue plus the ones you are trying to add, and when it is exceeded — in Trendyol’s own example, 60 existing + 45 new = 105 — all 45 of the variants you submitted are rejected. There is no partial acceptance. On a catalogue with many sizes and colours, counting the existing variants before a bulk upload is mandatory.
Content and image rules
Most rejection reasons accumulate here. The official limits:
- Product name: 3–200 characters excluding the brand name. (The API documentation says 100 characters in one place — there is a contradiction; staying under 100 passes both.)
- Model code: 1–40 characters, no URL or email address inside it.
- Description: the HTML field is 30,000 characters; the rejection documentation also mentions a 4,000-character description limit. These are probably two different fields; staying under 4,000 is the safe side.
- Images: at most 8; https:// required; JPEG/JPG/PNG/WEBP; 1 KB to 10 MB; minimum 860×574 px, maximum 2000×2000 px. The API documentation recommends 1200×1800 px at 96 dpi as ideal.
- The image link must point directly at the image; Google Drive and Dropbox links are not accepted; the link must contain no spaces or Turkish characters.
The most technical item here, and the one that wastes the most time: Trendyol fetches images from its own IP addresses. The addresses listed in the documentation are 89.32.128.66, 89.32.128.54-55, 89.40.131.40-41 and 89.40.131.76-77. If your CDN or firewall filters bot traffic, your images are rejected as “unreachable” and the error message makes you think the image itself is broken. If you are getting image rejections, the first place to look is your server logs.
On the content side two prohibitions are explicit: the description cannot contain personal contact details, external links or your own statement of sales/return terms (that falls under the “Misleading Statement” rejection code). There is also a brand-owner restriction: product information can only be updated by the brand owner, its authorised representative or the manufacturer in the Trendyol catalogue. So if you sell someone else’s brand you cannot touch the product page content — which means content quality cannot be your competitive advantage there. The weapons left are price, delivery and score.
The buybox: official factors and unofficial interpretations
Trendyol publishes the metrics it uses to calculate the buybox as six items: the product’s price, the seller score, the fast delivery option, the free shipping option, other campaigns on the product (the depth of the discount matters), and operational status. The numeric weightings are not published, but two sentences give the ranking away:
The most important factor for the buybox is the product’s selling price being more competitive than other sellers’.
When this status is red the seller is not included in the buybox ranking; when it is orange the seller is dropped to the bottom.
The second sentence matters enormously: if your operational status is red, you are outside the buybox race no matter what you do to your price. Cutting the price achieves nothing until the operational problem is fixed — it just eats your margin. Checking the colour of your status before entering a price war is the single most practical takeaway in this post.
Qualifying for the buybox: the brand side
There is one more gate in front of price and performance. To be included in the buybox, the product must have been sourced from the trademark owner registered with the Turkish Patent and Trademark Office, or from an authorised seller, and it must be entered under the brand it belongs to.
The flip side of that is a powerful tool for anyone with their own brand: when a “Seller-Based Trademark Infringement Notice” is created under Product > Documents and Registration > Infringement Notices, in Trendyol’s words the sellers’ products are closed for sale and are not reopened until they provide the required documents. Registering your trademark on a marketplace is not merely a legal step; it is a direct operational lever.
Hepsiburada and Amazon.com.tr
There is no public official documentation of Hepsiburada’s buybox criteria. On the API side there is a “Buybox Ranking Query” endpoint and a documentation category titled “Stock & Price & Buybox Management”, but how the winner is determined is not published. The criteria lists circulating online are third-party; do not turn them into operational rules.
The equivalent at Amazon.com.tr is the “Featured Offer”. The official definition: to be eligible to be the Featured Offer you must meet seller performance statistics and order volume conditions. Amazon’s global documentation is clearer on this, and two of its points correct a widespread misconception in Turkey: by Amazon’s own statement, customer reviews and star ratings are not taken into account in Featured Offer selection, and when all else is equal FBA and FBM are equally likely to be featured. So the claim “you cannot win the buybox without moving to FBA” contradicts Amazon’s own documentation.
Stock synchronisation: the quiet technical limits
Three rules in Trendyol’s stock and price update service determine your integration architecture:
- At most 1,000 SKUs per request.
- At most 20,000 units of stock per product.
- The same request body cannot be resent within 15 minutes — the system returns an error.
That third item explains why naive integrations built on “send the whole catalogue every five minutes” fail silently. The correct architecture is a delta mechanism that does not send what has not changed. Operations are also asynchronous: the result has to be followed with getBatchRequestResult — sending is not the same as done.
14 September 2026: the limit model changes
This is the most concrete technical risk of the coming period. Today there is no limit on Trendyol’s stock and price update service. From 14 September 2026 the limits will be per service group rather than per endpoint, and will vary by product-count tier. According to the published table, at the 50,000-product tier:
- Inventory & Price Write: 350 requests/minute (unlimited today)
- Product Integration Write: 200 requests/minute
- Product Integration Read: 1,000 requests/minute
Trendyol’s own example makes the situation clear: creating 50 products + 100 updates + 50 deletions within one minute = 200 requests → the write quota for that minute is used up. The tiers go up (75K, 150K, 500K, unlimited), but for a small or mid-sized seller the practical consequence is this: integrations that send SKUs one at a time will hit a wall after mid-September. The work required is known — 1,000-SKU batching and a queue mechanism. Ask your integrator about this now; asking in September is too late.
Overselling: a two-sided penalty
The failure-to-supply rate feeds both the seller score and the suspension risk. Trendyol’s official recommendations are dull but they work: verify physical stock, set a safety stock threshold, remove products you cannot supply immediately, update stock only after quality control, and work in coordination with your provider if you use an integration.
One item needs adding to that list: where a single product is sold across several channels, the safety stock threshold has to scale with the number of channels. A product with five units in stock, sold on three marketplaces, carries an overselling risk however short the synchronisation delay is. Keeping the last few units on a single channel rather than splitting them across channels produces fewer problems in most stores.
Setup order
- Write down your barcode policy. For codes you generate yourself, letters, digits and hyphens only; for restricted brands, a global barcode. Write it once and have everyone follow it — barcodes cannot be corrected.
- Count your existing variants and check the limit of 100. Then do the bulk upload.
- Test your image infrastructure. Verify that the Trendyol IPs can reach your images, and add a step that checks size and file limits automatically before upload.
- Look at the colour of your operational status. If it is red or orange, postpone any pricing work; you cannot enter the buybox on price alone.
- If you have your own brand, set up the registration and infringement notice mechanism.
- Prepare your integration for the 14 September 2026 limits: batching, a queue, getBatchRequestResult tracking, and a full catalogue re-push button.
Closing
In catalogue management, the gain comes less from doing the right thing than from noticing the wrong thing before it becomes irreversible. Barcodes, variant structure and brand matching are in that category: after approval they cannot be corrected, or they require opening a new product — which resets your accumulated reviews and sales history.
Price, stock and delivery time, by contrast, can be changed every day. If you want to spend your time on that second group, you have to set the first group up properly once.
Related reading
- The full mechanics of the seller score, the buybox’s most important input: marketplace seller score metrics.
- Seeing your margin before entering a price war: calculating real profit margin on marketplaces.
- Writing product descriptions for both the customer and search: getting cited by AI search.
The technical limits and rules in this post were compiled as of August 2026 from the Trendyol Seller Information Centre, developers.trendyol.com, developers.hepsiburada.com and Amazon’s official seller documentation. Limits and thresholds can change without notice; verify on the platform’s own documentation before making an integration decision.
Sources and official links
- Trendyol — Creating a Single Product Listing — Model code, variant and barcode rules, and which fields cannot be changed after approval
- Trendyol — Barcode FAQ for Product Entry — The “barcode already registered” error and the duplicate-listing violation
- Trendyol — Buybox Eligibility Rules — Brand ownership and authorisation conditions for buybox eligibility
- Trendyol — Metrics That Affect the Buybox — The official factors that determine buybox ranking
- Trendyol Integration Docs — Service Limits — Integration service limits and the quotas effective 14 September 2026
- Hepsiburada API Portal — Hepsiburada catalogue, stock, price and buybox services
Rules, fee schedules and platform policies change. The figures in this post reflect the position at the time of writing; confirm the current position from the official sources above before you act.
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