Legal Responsibility of Marketplace Platforms

Entrance

With the growth of e-commerce, marketplace platforms have become powerful digital commerce spaces that have surpassed traditional sales channels. Today, consumers often buy products not directly from the seller's own website, but from marketplaces that bring together numerous sellers on a single platform. This structure provides consumers with ease of product comparison, price review, fast payment, shipping tracking, and returns; while offering sellers the opportunity to reach a wider customer base.

However, the role of marketplace platforms is not limited to providing technical infrastructure. The platform facilitates order placement, manages the payment process, customizes the seller's page, displays product descriptions, provides campaign and advertising space, handles consumer complaints, operates the return system, influences seller ratings, and often builds trust among consumers. Therefore, the legal responsibility of marketplace platforms is one of the most important aspects of e-commerce law.

In Turkish law, this area is primarily considered in conjunction with the Law No. 6563 on the Regulation of Electronic Commerce , the Law No. 6502 on Consumer Protection , the Regulation on Distance Contracts , the Regulation on Service Providers and Intermediary Service Providers in Electronic Commerce , the Personal Data Protection Law (KVKK) , advertising legislation, and intellectual property provisions. The Ministry of Trade states that Law No. 6563 and its secondary regulations constitute the legal infrastructure for e-commerce; and that the amendments under Law No. 7416 aim to prevent illegal content, end unfair commercial practices against sellers in marketplaces, and ensure the healthy growth of e-commerce.

What is a Marketplace Platform?

A marketplace platform is an electronic commerce environment that facilitates the offering of goods and services by multiple sellers or service providers to consumers or buyers. According to Law No. 6563, electronic commerce is defined as online economic and commercial activity carried out electronically without physical interaction. The law defines an "intermediary service provider" as a natural or legal person who provides an electronic commerce environment for the performance of economic and commercial activities belonging to others; and an "electronic commerce intermediary service provider" as an intermediary service provider that enables the conclusion of contracts or the placing of orders for goods or services provided by service providers in the electronic commerce marketplace.

Within these definitions, a marketplace platform is a digital infrastructure where sellers list products, consumers place orders, payments are made, and post-sales processes are managed. While the platform may not be a direct intermediary between the seller and the consumer, it assumes numerous legal obligations as it mediates order creation, pre-information provision, cancellation notices, consumer applications, and data processing.

At this point, three actors must be distinguished: the seller or service provider, who offers the product or service; the marketplace platform, who acts as an e-commerce intermediary service provider facilitating the sale; the consumer or buyer , who purchases the goods or services. Depending on the type of dispute, liability may be directed solely at the seller, solely at the platform, or jointly at both.

Is the marketplace platform directly responsible for every product?

The fundamental principle regarding the responsibility of marketplace platforms is this: The platform is not the direct owner of every piece of content and every product offered by the seller. According to Article 9 of Law No. 6563, unless otherwise stipulated in other laws, the intermediary service provider is not responsible for any illegal matters related to the content offered by the service provider or the goods or services subject to that content. However, if the e-commerce intermediary service provider becomes aware that the content offered by the service provider is illegal, it must remove that content from publication without delay and report the illegality to the relevant public institutions and organizations.

This regulation shows that marketplaces do not have unlimited and automatic liability; however, they cannot remain passive once they become aware of the situation. For example, if a seller publishes counterfeit products, prohibited products, misleading health products, products infringing on trademarks, or clearly illegal content, the platform is obliged to take the necessary action once it becomes aware of this.

"Being informed" is crucial here. The platform can become aware of illegalities through complaints from rights holders, consumer notifications, letters from public institutions, court decisions, its own monitoring system, or clearly visible violations. It is not correct to hold every seller absolutely responsible for every advertisement before becoming aware of the illegality; however, failure to take action promptly after becoming aware of the illegality may result in liability for the platform.

The Responsibility of Marketplace Platforms in Intellectual and Industrial Property Infringements

One of the most common disputes in marketplaces involves claims regarding trademarks, designs, patents, copyrights, and counterfeit products. If a seller lists products using another person's trademark, sells counterfeit goods, infringes on visual or design rights, or offers counterfeit licensed products, a complaint can be filed with the marketplace platform.

According to Article 9/3 of Law No. 6563, upon a complaint from the rights holder regarding the infringement of intellectual and industrial property rights, the e-commerce service provider shall remove the product in question from publication and notify both the service provider and the rights holder. If the seller submits an objection based on information and documents contradicting the complaint, the product may be republished; the parties retain the right to appeal to judicial and administrative authorities.

This system obligates the marketplace platform to establish a "complaint-objection" mechanism. The rights holder must not only make abstract claims; they must submit applications with trademark registration, design registration, copyright, product link, a description of the infringement, and supporting evidence. The seller can also object by documenting that the product is original, that they have licensed sales rights, or that there is no infringement.

The platform needs to operate a neutral and documented process here. Unfairly removing a product can lead to losses for the seller; leaving a product online despite a clear infringement can cause harm to the rights holder and the consumer.

Liability of Marketplace Platforms from the Perspective of Consumer Law

Marketplace platforms hold particular importance in consumer law because consumers often conduct transactions through the platform interface, not directly with the seller. Orders are placed through the platform, payments are made through the platform, return requests are initiated via the platform screen, and consumer complaints are submitted to the platform's customer service.

According to the Ministry of Trade, intermediary service providers are jointly and severally liable with the seller or provider for providing, confirming, and proving that pre-information has been provided in distance contracts. If data entry is done by the intermediary service provider, the intermediary service provider is also responsible for any deficiencies in the mandatory information to be included in the pre-information. Furthermore, the platform is responsible for ensuring and proving that the information promised in advertisements and promotions made through the platform is consistent with the mandatory information to be included in the pre-information.

Therefore, the marketplace platform must establish the infrastructure to ensure that consumers are accurately informed about the product's essential characteristics, seller information, total price, shipping and additional costs, right of withdrawal, return conditions, and avenues for seeking redress. The presence of conflicting information on the product page, shopping cart screen, payment screen, and in the introductory text can lead to consumer disputes.

Platform's Liability in the Right of Withdrawal and Refund Process

In distance selling, consumers generally have the right to withdraw from the contract within 14 days without giving a reason. The Ministry of Trade states that the right of withdrawal in distance contracts can be exercised in writing or via a durable data storage medium; that exercising the right of withdrawal by telephone is not included in the legislation and may create proof issues.

A critical obligation for marketplace platforms is enabling consumers to easily submit and track their right of withdrawal. The Ministry states that intermediary service providers are obligated to establish a system that allows for the submission and tracking of withdrawal notifications regarding distance contracts concluded through the platform, to keep this system continuously operational, and to immediately notify the seller or provider of any notifications received through the system.

Therefore, simply directing the consumer to external channels by saying "contact the seller" is not always sufficient. If the consumer placed an order through the platform, the return request should also be trackable through the platform. The return code, shipping directions, notification to the seller, refund tracking, and application records should be kept in the system.

The Role of the Marketplace Platform in Refunds

When the right of withdrawal is exercised, the amount paid by the consumer must be refunded within the specified time. The Ministry of Trade states that in distance sales, the seller is obliged to refund the amount paid by the consumer within 14 days of receiving the withdrawal notification.

On marketplace platforms, payments are often processed through the platform system. Therefore, the platform bears significant practical responsibility in the refund process. If the consumer has paid the money to the platform rather than directly to the seller, the platform needs to properly manage the payment flow, the time it takes to transfer the money to the seller, the refund request, and the bank/payment institution integration.

Disputes can arise, particularly if a refund request is accepted but the refund is not issued, if the refund amount is insufficient, if shipping fees are unfairly charged, or if the consumer is pressured to purchase coupons/points. Due to its role in the payment system, the marketplace platform must manage these processes transparently and with proper documentation.

Prohibition of Unfair Trade Practices in Relations with Sellers

Marketplace platforms are not only responsible to the consumer. The commercial relationship between the platform and the seller is also protected under Law No. 6563. According to Article 1 of the Law, unfair commercial practices are prohibited in electronic commerce. Practices by an electronic commerce intermediary service provider that significantly disrupt the commercial activities of the seller for whom it provides intermediary services, reduce their ability to make reasonable decisions, or force the seller to become a party to a commercial relationship that they would not normally be a party to, are considered unfair.

The law considers certain practices to be unfair commercial practices in all cases. For example, failure to pay the seller the full sale price within five business days of the date the payment is received by the platform and the order reaches the buyer; forcing the seller to participate in promotional sales; failure to make the brokerage agreement clear and accessible in written or electronic form; making retroactive or unilateral changes to the seller's favor; charging for services not provided; and lowering the seller's ranking in the ranking system without objective criteria are all regulated as unfair commercial practices.

These regulations aim to limit the economic power of marketplace platforms over sellers. The platform cannot force a seller into mandatory campaigns, lower their ranking without just cause, charge unpredictable service fees, make retroactive contract changes, or arbitrarily delay payments.

Why is a Brokerage Agreement Important?

The relationship between the marketplace platform and the seller must be defined by an intermediary agreement, either in writing or electronically. The law requires this agreement to be clear, understandable, and easily accessible to the seller. The intermediary agreement should clearly specify the seller's acceptance conditions, commission rates, service fees, payment terms, campaign terms, return processes, product removal procedures, ranking and recommendation systems, termination, suspension, and appeal procedures.

Vague brokerage agreements make it easy for platforms to act unilaterally, creating significant commercial risks for sellers. Actions such as suspending a seller's account, removing their products, lowering their ranking, halting payment transfers, or forcing them to participate in campaigns must be based on objective, clear, and legally compliant terms specified in the agreement.

In the context of marketplace platforms, a well-prepared brokerage agreement protects not only the seller but also the platform itself. This is because, in the event of an audit or dispute, the platform must demonstrate that its transactions comply with objective contractual terms and the law.

Seller Information Verification and Reliability

According to Article 2 of the Annex to Law No. 6563, electronic commerce intermediary service providers are obligated to verify the identifying information of other e-commerce service providers through documents obtained from them or through publicly accessible electronic systems of the relevant institutions. Furthermore, they must enable the seller to include the information required in documents mandated by tax legislation on the marketplace where the sale takes place.

This obligation is important for consumer safety. Transactions conducted on the marketplace with false seller information, fake seller accounts, sales without invoices, brand imitation, or fraud increase the risk. The platform must verify the seller's identity, tax, trade name, MERSİS registration number, contact information, and similar details when accepting them into the system.

Verifying seller information is crucial not only for regulatory compliance but also for consumer trust. Consumers should know who they are buying the product from, who will issue the invoice, and who to contact in case of returns or complaints.

Personal Data Protection and Data Security

Marketplace platforms process a large amount of personal data. Consumers' names, addresses, phone numbers, email addresses, order history, payment information, return requests, reviews, cookie records, device information, and transaction security data are stored in platform systems. Sellers' business information, sales data, customer communications, and performance data may also be processed by the platform.

According to Article 10 of Law No. 6563, service providers and intermediary service providers are responsible for the storage and security of personal data obtained as a result of transactions carried out within the scope of the Law; they cannot transmit personal data to third parties without the consent of the data subject and cannot use it for other purposes.

In addition, the provisions of the Personal Data Protection Law (KVKK) also apply. The platform's role as data controller or data processor should be evaluated separately for each data processing activity. For example, the platform often acts as a data controller in terms of consumer accounts, order systems, and marketing activities. The transfer of data necessary for the seller to fulfill the order can be considered within the scope of contract performance; however, unnecessary data sharing, unauthorized data use for marketing purposes, or transfer abroad also create legal risks.

Using Vendor Data in Competition

One of the most sensitive issues for large marketplace platforms is the use of seller data by the platform for competitive purposes. According to Article 2 of the Annex to Law No. 6563, e-commerce intermediary service providers exceeding a certain net transaction volume threshold may only use the data they obtain from sellers and buyers for the purpose of providing intermediary services; they may not use this data to compete with sellers in the marketplaces or other e-commerce environments where they offer intermediary services.

This regulation aims to prevent platforms from gaining an unfair advantage over sellers by using their own branded products to manipulate sellers' sales performance, pricing, inventory, customer demand, and product data. Furthermore, providing sellers with the technical means to transfer and effectively access data related to their sales free of charge is also mandated for certain large platforms.

Therefore, the data governance of marketplace platforms must be carefully established not only in terms of the Turkish Personal Data Protection Law (KVKK), but also in terms of competition and e-commerce law.

Advertising, Campaign and Ranking Systems

Product visibility on marketplaces is largely determined by algorithms, advertising budget, seller rating, campaign participation, and referral systems. Therefore, the platform must manage its ranking and referral systems objectively, predictably, and in accordance with the contract.

The law considers it an unfair commercial practice to downgrade a seller in a ranking or recommendation system, or to restrict, suspend, or terminate services, if there are no objective criteria in the brokerage agreement or if the seller has appealed to public institutions or judicial authorities.

This regulation is particularly important in marketplaces where sellers become dependent on the platform. The platform's algorithmic ranking system should not be entirely arbitrary. Sellers should be able to understand which objective rules are used to determine rating reductions, ad visibility, campaign pressure, or store closures.

Brand Usage and Search Engine Advertising

Trademark usage is a specific topic within the legal responsibility of marketplace platforms. According to Article 2 of the Annex to Law No. 6563, an e-commerce intermediary service provider may not conduct marketing and promotional activities on online search engines using the registered trademark that constitutes the main element of the e-commerce service provider's domain name registered with ETBİS, without obtaining prior written or electronic consent.

This regulation restricts platforms from driving traffic by running search engine ads using sellers' brands. For example, a platform advertising using a seller's registered trademark or domain name without the seller's explicit consent could create legal risks.

This provision is important for sellers. Sellers who open a store on a marketplace platform must clearly state in their brokerage agreement whether or not they allow their brand to be used by the platform for advertising purposes.

ETBIS Registration and Notification Obligation

ETBİS is a system established for the registration of e-commerce service providers and e-commerce intermediary service providers, the collection of e-commerce data, and the production of statistical information. Law No. 6563 defines ETBİS as an information system created by the Ministry that enables registration and notification within the scope of the law.

The Ministry of Trade also states that ETBİS was created to ensure the accessibility of e-commerce businesses and the accurate tracking of e-commerce data; and that service providers and intermediary service providers engaged in electronic commerce or electronic commerce brokerage activities must register with ETBİS via e-Government before commencing operations.

For marketplace platforms, ETBİS registration is one of the fundamental obligations in terms of transparency and oversight. However, ETBİS registration alone does not mean that all legal compliance is complete. The platform must also fulfill its obligations regarding consumer law, data security, seller contracts, management of illegal content, return system, and advertising.

Record Keeping and Ministry Supervision

Law No. 6563 grants the Ministry broad supervisory powers. The Ministry may request all types of information, documents, ledgers, and electronic records, including those kept electronically; those concerned are obliged to provide them completely and truthfully. Intermediary service providers and service providers are required to retain information, documents, ledgers, and electronic records related to their business and transactions within the scope of the Law for a 10 years .

This obligation is extremely important for marketplace platforms. Order records, seller agreements, return requests, consumer complaints, product removals, intellectual property complaints, payment transfer records, campaign approvals, ranking changes, and audit reports must be regularly maintained.

Failure to maintain complete records prevents the platform from proving its innocence in the event of a dispute. System records are the most important evidence, especially in consumer disputes, seller complaints, and Ministry audits.

Administrative Fines and Sanction Risk in 2026

Marketplace platforms' failure to comply with regulations can result in significant administrative fines. According to Article 12 of Law No. 6563, the administrative fines to be applied in 2026 25.49% , the revaluation rate, as per the Circular dated December 25, 2025. The Circular entered into force on January 1, 2026.

The law prescribes different administrative fines for a wide range of violations, including failure to remove illegal content, unfair commercial practices, non-compliance with Ministry inspection requests, breaches of certain major platform obligations, payment deadlines, brokerage agreements, and advertising and discount budget limitations. Some violations are subject to fixed administrative fines, while others are proportional to net sales revenue or net transaction volume.

Furthermore, in cases of serious violations, the Ministry may set a deadline for the violation to be rectified; if it is not rectified, increasing administrative fines may be imposed, and ultimately, a decision to remove the content or block access to the relevant websites may be considered.

Compliance Checklist for Marketplace Platforms

To mitigate the legal risks of marketplace platforms, robust seller acceptance and verification processes must be established. The seller's identity, tax information, trade name, contact information, and any trademark authorizations should be checked.

Secondly, the brokerage agreement with sellers should be clear, understandable, and accessible. Commission, payment terms, campaign conditions, service fees, suspension, termination, product removal, and appeal mechanisms should be objectively regulated.

Thirdly, the consumer must be provided with complete pre-information and a full explanation of the distance selling contract process. Product information, seller information, total price, shipping, right of withdrawal, and avenues for redress must be clearly displayed.

Fourthly, the return and cancellation system must function seamlessly. Consumers should be able to submit their applications through the platform, track their applications, and receive automatic notifications to the seller.

Fifth, a fast, registered, and appealable procedure should be established for complaints regarding illegal content and intellectual property.

Sixth, personal data should only be processed for necessary purposes, the security of vendor and consumer data must be ensured, and data sharing and marketing activities must be conducted in accordance with the Personal Data Protection Law (KVKK).

Seventh, electronic records for Ministry audits must be kept for at least 10 years; all business and transactions must be accurately documented.

Conclusion

The legal responsibility of marketplace platforms is not limited to their role as "non-seller intermediaries" in the classic sense. These platforms directly influence the e-commerce ecosystem, from order creation and payment flow to consumer information, return processes, seller visibility, advertising and campaign management, data processing activities, and the management of illegal content. Therefore, the responsibility of marketplace platforms should be evaluated holistically in terms of consumer law, e-commerce law, GDPR, intellectual property, unfair trade practices, and administrative sanctions.

According to Law No. 6563, intermediary service providers are, as a rule, not directly responsible for any illegalities related to the content and product offered by the seller; however, upon becoming aware of illegal content, they must remove it without delay and report it to the relevant authorities. In cases of intellectual and industrial property infringements, the product must be removed from publication upon the complaint of the rights holder, supported by information and documents, and the seller must be given the opportunity to object.

From a consumer law perspective, the responsibilities of platforms are more concrete. The intermediary service provider may be jointly responsible with the seller for providing, confirming, and proving the pre-information; they must also establish a system that allows for the notification and tracking of the right of withdrawal through the platform.

In their dealings with sellers, marketplace platforms must comply with the prohibition against unfair trade practices. They must not delay seller payments, force sellers to participate in campaigns, make retroactive or unilateral contract changes, charge for services not provided, or lower sellers' rankings without objective criteria.

In conclusion, legal compliance for marketplace platforms is not completed simply by publishing the relevant legislation or registering with ETBİS (Electronic Public Procurement System). A robust seller verification system, transparent brokerage agreements, clear consumer information, an effective return mechanism, a swift procedure for illegal content, data security, record keeping, and regular internal audit processes must be established. Otherwise, the platform may face consumer complaints, seller disputes, trademark infringement claims, GDPR risks, Ministry audits, and high administrative fines.