Trendyol API October Timeline: Legacy Order Service Shuts Down, Origin Field Becomes Mandatory

According to the change logs (changelog) on Trendyol's developer page, October 2026 has three critical dates: October 8 is the deadline for complying with the new return rejection reasons, October 15 is the day the legacy order service is retired, and October 23 is the day the "origin" field for country of origin becomes mandatory in product services. These Trendyol API changes directly affect sellers who manage their orders, products and returns through integration software or their own software. Sellers who work only through the seller panel are not directly affected by the API change; however, accurate country-of-origin information on their products matters for them too.

Trendyol API changes: September–October timeline

Legacy order service shuts down on October 15

If your integration still fetches orders from the legacy service, new orders may not reach your software after October 15. That means invoicing, shipping labels and stock deductions all break down at the same time. Your software provider handles the migration, but confirming that it has been completed and checking the order flow in the days following October 15 is up to you. We explain how stock and invoice flows connect after an order in our articles what is stock synchronization and automatic e-invoices (e-Fatura) from marketplace orders.

Country of origin: origin field mandatory on October 23

Trendyol has separated country-of-origin information from product attributes and moved it to a standalone "origin" field in product services. For products that have origin information in their product attributes, the data is automatically moved to the new field. Products with no origin information at all, however, are at risk: once the field becomes mandatory, create and update requests for these products may run into problems.

The payment method field is useful for invoicing too

Since September 8, 2026, order package and webhook responses also include the paymentMethod field, which shows the order's payment method. Because an e-archive invoice (e-Arşiv) issued for an online sale must include the payment method and payment date, this field can be used directly on the invoicing side; if your integration takes this information from the order instead of having it entered manually, the margin for error shrinks. The full list of mandatory fields on the invoice is in our article on e-Arşiv invoice details for online sales.

Return rejection reasons must be updated by October 8

Six of the reasons that can be selected when rejecting a return request have been deactivated, and three new reasons have been added. Sellers who manage returns through an integration should make sure their software uses the new list of reasons by October 8. Trying to select a deactivated reason may prevent the return rejection from being completed.

What should you do as a seller?

• Ask your software provider three questions: Has the switch to the V2 order service been made, is the origin field being sent, and has the list of return rejection reasons been updated?
• Check that country-of-origin information on your products is filled in and correct; complete any missing entries before October 23.
• Use the new list of reasons when rejecting returns; if you can't select an old reason, this change is why.
• During the week of October 15, compare the number of orders in the Trendyol panel with the number of orders reaching your software every day.
• If you use your own software, follow the change logs on Trendyol's developer page regularly.

If you're curious about how integration works in general, you can also read our article what is marketplace integration.