---
type: Statutory Article
title: "Article 4 — The rights and obligations of users and data holders with regard to access, use and making available product data and related service data"
description: "Whatever the vendor can see of your system's data, you can demand — free, machine-readable, live. The custody question stops being 'may I?' and becomes 'how well?'."
resource: "https://eur-lex.europa.eu/eli/reg/2023/2854/oj/eng"
tags: ["eu-data-act", "chapter-ii", "access"]
instrument: eu-data-act
article: 4
chapter: "II"
binds: ["data-holder", "user"]
applies_from: 2025-09-12
cross_refs: [3, 5, 8]
attaches_to: ["air", "cloud", "controller", "door", "head-end", "local-ai", "meter", "occupancy", "web-client"]
legal_review: none
generated: { by: claude-code/opus-5.5, at: "2026-10-09T00:00:00Z" }
status: draft
sources:
  - id: eli
    resource: "https://eur-lex.europa.eu/eli/reg/2023/2854/oj/eng"
    title: "Regulation (EU) 2023/2854, Official Journal"
  - id: prototype
    resource: "https://github.com/DavidJCrawford/stewardship-explorer/blob/main/src/data/act.json"
    title: "stewardship-explorer act.json (author's summaries, July 2026)"
---

# Precise reading

Where data is not directly accessible from the product/service, the data holder must make readily available data (and metadata) available to the user without undue delay, free of charge, in the same quality as available to itself — continuously and in real time where applicable. Trade-secret protections apply via proportionate measures, not blanket refusal; use of the data by the data holder itself requires a contractual basis.[^eli]

*A faithful summary of the operative demand, not the statutory text.*

# Plain reading

Whatever the vendor can see of your system's data, you can demand — free, machine-readable, live. The custody question stops being 'may I?' and becomes 'how well?'.

*Paraphrase.*

# Facts

| | |
| --- | --- |
| Chapter | II — [Business to Consumer and Business to Business Data Sharing](/law/eu-data-act/chapters.md) |
| Binds | [Data Holder](/law/eu-data-act/actors.md), [User](/law/eu-data-act/actors.md) |
| Applies from | 2025-09-12 |
| Cross-references | [Article 3](/law/eu-data-act/articles/article-03.md), [Article 5](/law/eu-data-act/articles/article-05.md), [Article 8](/law/eu-data-act/articles/article-08.md) |
| Where it attaches in the building | [air](/building/components/air.md), [cloud](/building/components/cloud.md), [controller](/building/components/controller.md), [door](/building/components/door.md), [head-end](/building/components/head-end.md), [local-ai](/building/components/local-ai.md), [meter](/building/components/meter.md), [occupancy](/building/components/occupancy.md), [web-client](/building/components/web-client.md) |

# Rights that rest on it

- [The data your building makes is yours to take.](/rights/yours.md)

[^eli]: Regulation (EU) 2023/2854, Official Journal