The Turkish E-Commerce Integration Playbook: Trendyol, iyzico, Shipping, and e-Invoicing

Building an e-commerce store in Turkey is not the same as spinning up a Shopify account and pointing it at a U.S. payment gateway. The local ecosystem has its own rules, its own dominant players, and its own integrations that you cannot skip. If you are launching — or if your current platform handles them poorly — this is the practical map.

The Four Pillars

Turkish e-commerce success rests on four integration pillars. Get any of them wrong, and you bleed customers or cash.

1. Marketplace sync — because much of your volume will not happen on your own site.
2. Local payment providers — because Turkish shoppers expect installments and local cards.
3. Shipping carriers — because delivery expectations are specific and "free shipping" here means something different.
4. e-Invoicing — because it is the law, not a nice-to-have.

Let's take them one at a time.

Marketplace Sync: Trendyol, Hepsiburada, N11

In most Western markets, DTC brands can ignore marketplaces for years. In Turkey, they usually cannot. Trendyol alone accounts for a huge share of online retail traffic, especially in fashion, home, and beauty. Hepsiburada dominates electronics and big-box. N11 still has meaningful long-tail reach.

Good marketplace sync handles:

• Catalog push: sending product data (title, images, descriptions, variants) from your core platform to each marketplace with the specific fields each one requires. Trendyol's category tree is different from Hepsiburada's. Attribute requirements vary per category.
• Inventory sync: real-time or near-real-time stock updates so you do not oversell. Nothing burns a merchant like a marketplace order coming through on an item the retail store already sold.
• Price and campaign control: channel-specific pricing rules, marketplace commissions factored in, automated participation (or not) in Trendyol's frequent campaigns.
• Order ingestion: pulling marketplace orders into your core OMS so fulfillment is unified. Treating marketplace orders as "another channel" rather than a separate silo is where scale gets unlocked.

Manual management fails past a few hundred SKUs per marketplace. By the time you have a few thousand, a proper sync layer is non-negotiable.

Payments: iyzico and PayTR

Turkish shoppers expect two things that most global payment providers do not offer cleanly: installments (taksit) and local card types (Bonus, Axess, World, Maximum, Paraf, etc.). Stripe or Adyen can process these in theory, but iyzico and PayTR are built around them natively.

What good payment integration looks like:

• Installment campaigns mapped at the cart level, not hardcoded. A shopper putting 2,000 TL of electronics in the cart should see Bonus card's 3-month installment offer without a developer writing a new rule.
• 3D Secure done right — SCA everywhere, but with fallback flows for cases where the bank's 3DS infrastructure fails. Far too many Turkish checkouts leak conversion at the 3DS step.
• Installment-aware refunds — partial refunds on installment orders have specific mechanics that matter at accounting time.
• Vaulting with appropriate tokenization so repeat customers do not re-enter card details.

One caution: never trust the frontend-calculated total. Always recompute server-side against cart contents before calling iyzico, and validate the paid price against your server total on callback. The backend is the source of truth for money movement. It is not optional.

Shipping: MNG, Yurtiçi, Aras, PTT

Turkish last-mile is a fragmented market. MNG Kargo, Yurtiçi Kargo, Aras Kargo, PTT Kargo, and Sürat Kargo are the main players, each with different strengths — geographic coverage, next-day reach, handling of oversized items, integration quality.

A robust shipping layer offers:

• Dynamic carrier selection based on weight, dimensions, destination district (ilçe), and merchant agreements. Not every carrier services every rural village.
• AWB (Airway Bill) creation via API — you generate a shipping label by calling the carrier's endpoint, not by copying order data into their portal manually.
• Real-time status tracking propagated back to the customer portal. "Where is my order?" should never require the customer to open a carrier's site.
• Reconciliation — carriers sometimes bill differently than quoted. A good integration catches discrepancies at the invoice level.

Returns deserve their own design. Turkish e-commerce has high return rates compared to global averages, especially in apparel. A return label flow that works in a few taps from the customer side, with a scheduled pickup, reduces support load more than any other single investment.

e-Invoicing: the GIB Compliance Stack

e-Fatura and e-Arşiv Fatura are not optional. Above certain revenue thresholds and for certain transaction types, you must issue electronic invoices through the Revenue Administration (GIB) system. Rules have evolved — the thresholds that kick you into mandatory e-Fatura have come down over the past few years, and more transaction categories keep getting pulled in.

A proper e-invoicing integration covers:

• Automated invoice issuance on order confirmation or on shipment (depending on your tax setup) with correct XML formatting and UBL compliance.
• Integration with the GIB Portal directly or via an accredited integrator — the integrator route is usually the pragmatic choice for operational scale.
• Connection to the merchant's accounting system — Logo Tiger, SAP, Mikro, Luca — so every invoice flows into the ERP without double-entry.
• Handling returns and cancellations with proper reverse-invoicing (iade faturası) rather than silent database updates.

Skipping the last point is where small operations get in trouble with the tax office.

The ERP Layer: Where Everything Meets

Once you scale past a certain point, your ERP (Logo, SAP, Mikro, Netsis, Luca) becomes the backbone. Orders come from marketplaces and your own site. Payments are captured through iyzico and PayTR. Shipping is handled across multiple carriers. e-Invoices flow to GIB. Somewhere all these events need to land in accounting with correct VAT treatment, stock movements, and customer records.

A modern e-commerce platform for the Turkish market should treat the ERP connection as a first-class citizen, not an afterthought. One-way sync is not enough — the ERP needs to push price updates, stock adjustments, and invoice status back to the storefront.

Do Not Underestimate the Last 10%

The easy part of all of this is the API documentation. Trendyol has docs. iyzico has docs. MNG has docs. GIB publishes specs. Building the basic integration is achievable.

The hard part — and the reason most merchants end up switching platforms — is the last 10%: the reconciliation edge cases, the carrier-specific oversize rules, the Trendyol campaign that breaks your pricing logic, the iyzico webhook that does not arrive when the customer's bank is slow, the GIB outage during peak sales days.

Platforms built specifically with the Turkish market in mind carry this institutional knowledge in their code. Generic platforms with a "Turkey adapter" bolted on usually do not. When you are evaluating options, dig into how the platform handles failure cases, not just happy paths.

Starting Point for 2026

If you are launching or replatforming this year, the baseline stack looks like:

• Core platform with first-class support for multi-tenant, multi-storefront operations
• Trendyol + Hepsiburada sync from day one, N11 if relevant to your category
• iyzico as primary gateway, PayTR as secondary (provider redundancy matters on Black Friday scale days)
• Two shipping carriers minimum with automatic failover
• Accredited e-Invoicing integrator, direct ERP connection
• Server-side order and payment validation — always

Get these right and the rest of your e-commerce operation has a solid foundation. Skip them, and you will rebuild them under pressure at the worst possible time.