The European Union’s Digital Markets Act reached its first full compliance deadline Thursday, forcing six of the world’s largest technology companies to change products, business practices and technical interfaces across Europe. Apple, Alphabet, Meta, Amazon, Microsoft and ByteDance must now demonstrate that the digital services the European Commission designated as “gatekeepers” comply with obligations intended to make online markets more contestable and reduce the power of dominant platforms over users and business customers.

The European Commission said the March 7 deadline applies across core platform services including search engines, app stores, operating systems, online marketplaces, advertising systems, social networks and messaging. The six companies are required not only to implement changes but also to publish reports explaining how they believe those changes satisfy the law.

A new competition regime moves from legislation to product design

The DMA differs from traditional antitrust enforcement because many obligations apply in advance rather than only after regulators prove a specific violation. Gatekeepers must permit certain forms of interoperability, give users more control over defaults and data sharing, allow business users greater freedom to reach customers outside dominant platforms and avoid using their control of a platform to unfairly favor their own services.

For Alphabet, the compliance work is already visible to users. In a March 5 Google explanation, the company said it had implemented more than 20 changes to Search in Europe, added additional browser and search-engine choice screens, expanded data-portability tools and changed how consent works when personal data is shared across Google services. Google also said app developers have more options for billing and for directing users to offers outside Google Play.

Those changes come with trade-offs. Google said redesigned search results could send more traffic to aggregators and comparison services while reducing traffic to hotels, airlines, restaurants and merchants that previously benefited from direct Google modules. Reuters reported that the company was rolling out the changes days before the deadline while warning that some DMA requirements could alter product quality and business economics.

Apple opens parts of an ecosystem it built to keep tightly controlled

Apple faces some of the most visible structural changes because the DMA directly affects the iPhone distribution model in the European Union. The company’s January compliance plan includes more than 600 new APIs, support for alternative app marketplaces, alternative payment processing, browser engines other than WebKit and new browser-choice controls.

For developers, those changes create routes around the App Store that have never existed on the iPhone in ordinary consumer use. Apple is simultaneously introducing notarization, authorization and disclosure requirements that it says are necessary to limit malware, fraud and privacy risks. It has also created new business terms, including a core technology fee for some developers that choose the alternative DMA framework.

The result is an unusual experiment: the same hardware platform will operate under substantially different distribution rules depending on whether the user is in the European Union. Apple argues that the law forces it to reduce protections that are integral to the iPhone model. European regulators argue that a company controlling both the operating system and the dominant distribution channel should not be able to dictate every route by which competing software reaches customers.

Messaging interoperability becomes a technical requirement

Meta is confronting a different kind of opening. The DMA requires designated messaging services to support interoperability with qualifying third-party services. On March 6, Meta published a detailed engineering explanation describing how WhatsApp and Messenger will connect with outside providers while seeking to preserve end-to-end encryption and other security guarantees.

The first phase covers one-to-one text messages and sharing images, voice messages, video and files. Meta says third-party providers must meet defined technical and security requirements and may use the Signal protocol or demonstrate an equivalent level of protection. Users will have to opt into interoperability rather than receiving third-party messages automatically.

The requirement tests whether regulators can lower network-effect barriers without weakening the security properties that make encrypted messaging useful. A competing service may gain access to WhatsApp users without persuading every contact to switch platforms, but both companies must coordinate protocols, identity handling, spam defenses and encryption in ways that do not expose users to new vulnerabilities.

Windows and LinkedIn also change under the gatekeeper rules

Microsoft said Thursday that DMA-compliant versions of Windows 10 and Windows 11 are now available in the European Economic Area and are rolling out automatically. In its compliance announcement, the company highlighted changes that give users more freedom to uninstall certain built-in applications, alter defaults and use third-party services. LinkedIn is also changing how it combines data and presents personalized services in Europe.

Microsoft argues that Windows already met many DMA principles because it has long allowed software installation outside a centralized store. Even so, the law reaches deeper into defaults, data combination and platform treatment, requiring changes that would not necessarily have resulted from ordinary market pressure.

Amazon and ByteDance must likewise comply for their designated services, while the Commission will evaluate reports and gather feedback from businesses, developers and consumers. The legal penalties are significant: violations can lead to fines of up to 10% of worldwide annual turnover and higher penalties for repeated noncompliance.

The central question shifts from promised changes to effective competition

The March 7 deadline does not settle whether the companies have complied. It begins the period in which regulators, competitors and users will test whether the measures work in practice. A browser choice screen can technically offer alternatives while still nudging users toward the incumbent. An app-store policy can allow outside payment while attaching fees that make the option unattractive. A messaging interface can exist on paper while remaining too difficult for smaller services to implement.

That is why the DMA’s next phase will be judged less by the number of new settings and APIs than by whether rivals can realistically use them. The Commission’s deadline notice says gatekeepers must prove “effective compliance,” language that gives regulators room to examine outcomes rather than accept formal changes at face value.

For Europe’s technology market, this week marks a transition from years of debate over platform power to direct intervention in product architecture. Apple is opening iPhone distribution, Google is changing search and data practices, Meta is preparing encrypted messaging interoperability, and Microsoft is altering Windows and LinkedIn. Whether those interventions generate durable competition without unacceptable losses in security, simplicity or product quality will determine whether the DMA becomes a model for digital regulation or a uniquely European experiment.