What is the DSA?

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Understanding the EU's rulebook for online platforms, marketplaces and digital intermediaries.

For researchers, the Digital Services Act (DSA) can be a powerful tool. Yet in our experience, it is still not widely known, and working with it is not yet common practice in research teams. In this first part of our series, we introduce the regulation: what it is, who it applies to, and what it requires, and we share the key resources for anyone who wants to dive deeper. Part 2 then looks specifically at what the DSA means for Open Science.

The Digital Services Act, usually shortened to DSA, is one of the European Union's central legal instruments for regulating online services. It applies to a wide range of digital intermediaries, including online platforms, social networks, app stores, online marketplaces, and travel or accommodation platforms. Its overall aim is to make the online environment safer, more transparent and more accountable for users in the EU.

The DSA was adopted as Regulation (EU) 2022/2065 of 19 October 2022 and entered into force in November 2022. Because it is a regulation, it applies directly across EU Member States. Its full title is: Regulation (EU) 2022/2065 on a Single Market For Digital Services and amending Directive 2000/31/EC.

At its core, the DSA updates the EU framework for digital services. It does not replace all existing internet, consumer protection, media, data protection or criminal law rules. Instead, it creates a horizontal framework for how online intermediaries should handle risks, illegal content, transparency, user rights, advertising and accountability.

Why was the DSA introduced?

Digital services have become part of everyday life. People use platforms to communicate, buy goods, access information, organise communities, search for services and participate in public debate. At the same time, online environments can amplify risks: illegal products, hate speech, disinformation, scams, unsafe services, opaque advertising, manipulative design, and harmful content for minors.

The DSA responds to these challenges by creating common EU-wide rules. Its guiding idea is often summarised as: what is illegal offline should also be addressed online. However, the DSA does not only deal with illegal content — it also introduces transparency and accountability duties, especially for the largest platforms and search engines.

Who does the DSA apply to?

The DSA uses a layered system of obligations: the more central and influential a service is, the more demanding the obligations become. It covers four broad categories:

Intermediary services — basic infrastructure that transmits or stores user information.
Hosting services — services that store user-provided information, such as cloud or web hosting.
Online platforms — services that store and disseminate information to the public at users' request, including social media, app stores and online marketplaces.
Very Large Online Platforms (VLOPs) and Very Large Online Search Engines (VLOSEs) — platforms or search engines with more than 45 million monthly active users in the EU, subject to the strictest rules.

The European Commission maintains an updated list of designated VLOPs and VLOSEs, since designation can change over time.

What does the DSA require?

Online platforms must let users report illegal content, goods or services; explain content moderation decisions; and provide complaint and redress mechanisms. They must also be more transparent about advertising and recommender systems. Online marketplaces face additional obligations to improve trader traceability and reduce the sale of illegal products.

For VLOPs and VLOSEs, the obligations go further. They must:

assess and mitigate systemic risks — including illegal content, fundamental rights, civic discourse, electoral processes, public security, gender-based violence, public health, minors and mental wellbeing;
undergo independent audits;
meet enhanced transparency obligations, including through transparency databases and data access for vetted researchers.

Enforcement: who checks compliance?

The DSA is enforced through a cooperation system involving the European Commission and national authorities called Digital Services Coordinators.

Digital Services Coordinators are national authorities responsible for supervising and enforcing the DSA in Member States, helping the Commission monitor and enforce obligations under the DSA.

The European Commission has direct supervisory and enforcement powers over designated VLOPs and VLOSEs. Its supervision page provides an overview of designated platforms and search engines, along with main enforcement activities.

What transparency tools does the DSA create?

One of the most practical resources created under the DSA is the DSA Transparency Database. Online platforms must submit "statements of reasons" explaining certain content moderation decisions, making it possible to track moderation activity close to real time.

The database is useful for researchers, journalists, civil society organisations, regulators and policymakers looking to identify patterns in enforcement and platform behaviour. Researchers have also pointed out limitations, including inconsistencies in reporting and differences in how platforms use the database.

How can researchers access platform data?

Article 40 of the DSA is particularly relevant for Open Science: it creates pathways for verified researchers to request access to platform data to study systemic risks in the EU, backed by a delegated act that sets out the rules for vetted researchers to obtain this access. Part 2 of this series looks at how this process works in detail, and why it matters for Open Science.

What are trusted flaggers?

The DSA introduces the role of trusted flaggers: organisations designated by national Digital Services Coordinators because of their expertise in identifying specific types of illegal online content, such as hate speech, terrorist content or illegal products. Platforms must treat their notices with priority, improving the quality and speed of enforcement.

How does the DSA protect minors?

On 14 July 2025, the European Commission published guidelines on the protection of minors under the DSA, aiming to ensure a high level of privacy, safety and security for children and young people online. This area is especially relevant for educators, parents, child rights organisations, digital rights groups, platforms and policymakers.

Conclusion

The Digital Services Act is not only a legal text for lawyers or platform compliance teams — it is a new governance framework for the digital public sphere in Europe, covering transparency, accountability, user rights, illegal content reporting, systemic risk assessment, researcher access and child protection.

Understanding the legal instrument is the first step. The next step — covered in Part 2 of this series — is understanding why it matters for Open Science, and how it can support public-interest scrutiny of digital platforms.

Further readings: