# EU digital rules: auditing the algorithms behind platforms

**EU digital algorithm regulation** moved from principle to enforcement with the Digital Services Act, in force since 16 November 2022. The regulation obliges very large online platforms to assess and mitigate the systemic risks their systems create, and it gives the European Commission the means to examine how their algorithms actually work. The European Centre for Algorithmic Transparency, opened in Seville, is the technical body behind that oversight.

## What the centre does

ECAT operates under the Commission's Joint Research Centre. Its team combines data science, artificial intelligence, social science and law, and its task is to analyse the functioning of recommendation and moderation systems used by large platforms such as Facebook, Google, Instagram, TikTok, LinkedIn, Bing and X. The goal is to understand how algorithmic choices shape what users see, and to contain the spread of illegal or harmful content.

The centre's work covers risk management and transparency. It develops best practices for assessing how algorithms affect users and for mitigating the effects that regulators consider harmful. Because the same technical questions underpin several European rules, ECAT also contributed to the drafting of the AI Act, where documentation, risk classification and evaluation obligations follow a similar logic.

## Why algorithmic transparency is difficult

Platforms are opaque by design. Recommendation systems are complex, they change continuously and their effects depend on data that is not public. Auditing them requires access to internal information, agreed methods and researchers able to interpret the results. The Digital Services Act addresses this by requiring risk assessments, independent audits and data access for vetted researchers, which turns transparency from a voluntary gesture into a legal obligation with reporting duties.

## What it means for companies

Most businesses are not the direct target of these rules, and they are affected indirectly. The platforms they advertise, sell and communicate on must now document and justify their systems, and that changes the environment in which digital marketing and content distribution operate. Companies that understand the framework can ask better questions of their agencies and suppliers, and they can anticipate how platform policies evolve. For any organisation using AI, the same principles of documentation, risk assessment and explainability are becoming a practical requirement rather than a matter of good intentions.

Auditing an algorithm starts from what the vendor admits, and [the documented vulnerabilities of OpenAI](/en/ecorner/2025/openai-vulnerabilities-risk.html) are a case study in how fast that record grows.

## Frequently asked questions

**Which platforms fall under the Digital Services Act obligations?**
The strictest duties apply to very large online platforms and search engines, designated by user numbers. Smaller intermediaries carry lighter obligations.

**What is algorithmic transparency in practice?**
It means documenting how a system ranks, recommends or moderates content, assessing the risks it creates and allowing independent scrutiny under defined conditions.

**Does this regulation apply to a small business?**
Not directly in most cases. It shapes the conduct of the platforms a small business depends on, which affects reach, advertising and data access.

**How does it relate to the AI Act?**
Both use risk-based obligations and documentation. The Digital Services Act targets platform conduct, while the AI Act targets AI systems and their providers.

## Sources

European Centre for Algorithmic Transparency — https://algorithmic-transparency.ec.europa.eu/index_en
European Commission — the Digital Services Act — https://digital-strategy.ec.europa.eu/en/policies/digital-services-act
European Commission — press release on the launch of ECAT — https://ec.europa.eu/commission/presscorner/detail/en/ip_23_2186
Joint Research Centre — science for EU digital policy — https://joint-research-centre.ec.europa.eu/index_en