As of mid-2026, mandatory XBRL tagging for ESRS sustainability statements is not yet in force. EFRAG (the European Financial Reporting Advisory Group) handed its proposed taxonomy to the European Commission and ESMA in August 2024, but the Regulatory Technical Standard that would formally mandate tagging is still being finalised. See our CSRD Omnibus guide for the current timeline.
The short version
ESRS XBRL is the digital taxonomy developed by EFRAG for tagging sustainability statements prepared under the European Sustainability Reporting Standards (ESRS) — the disclosure standards that sit underneath the EU's Corporate Sustainability Reporting Directive (CSRD). It works the same way financial XBRL tagging does: individual disclosures (greenhouse gas emissions, workforce metrics, governance disclosures) get wrapped in machine-readable tags mapped to a standard taxonomy element, alongside the human-readable narrative report.
Why it exists
The EU has required XBRL tagging for financial statements since 2020 under the European Single Electronic Format (ESEF). The logic behind extending this to sustainability reporting is the same: if thousands of companies are reporting under the same ESRS standards, regulators and investors should be able to compare that data by machine, not just by a person reading narrative text.
What's actually tagged
The ESRS structure covers two cross-cutting standards (ESRS 1: General Requirements, ESRS 2: General Disclosures) and ten topical standards spanning environmental (E1–E5), social (S1–S4), and governance (G1) disclosures. EFRAG's taxonomy maps each individual disclosure requirement — over a thousand distinct data points — to a tag, though a company only tags what's actually material and applicable to its own reporting, not every possible data point.
iXBRL, not separate-file XBRL
Like the EU's financial reporting format, sustainability tagging uses Inline XBRL (iXBRL) — the tags are embedded directly inside the human-readable XHTML report, rather than living in a separate data file. Open the file in a browser and it reads like a normal sustainability report; the tags sit invisibly in the underlying code.
Where things actually stand
EFRAG published its draft ESRS XBRL taxonomy for public consultation in February 2024, and handed the finalised proposal to the European Commission and ESMA in August 2024. From there, ESMA is responsible for developing the Regulatory Technical Standard (RTS) that would formally require tagging. As of the most recent public tracking on this (late 2025 into 2026), that RTS has not been finalised — it's been caught up in the same broader "Omnibus" simplification process that has substantially narrowed who has to report under CSRD at all. See our CSRD Omnibus guide for the detail.
Should you prepare anyway?
If your company is still in scope for CSRD reporting after the Omnibus changes, we'd suggest preparing your sustainability data with tagging in mind regardless of the exact mandate date — structuring your data collection around the ESRS taxonomy now avoids a scramble once the RTS is confirmed, and companies that already produce XBRL-tagged financial statements will find much of the underlying process familiar.
Frequently Asked Questions
Is ESRS XBRL tagging mandatory right now?
No — as of mid-2026, the Regulatory Technical Standard that would formally mandate it hasn't been finalised, and EFRAG is separately rebuilding the taxonomy itself to match the newly revised ESRS (2026) standards, targeting completion by December 2026. See our CSRD Omnibus guide for the current status.
Is ESRS XBRL the same as ESEF?
No, though closely related — ESEF is the EU's existing financial-statement tagging format (in force since 2020). ESRS XBRL is a separate, newer taxonomy specifically for sustainability statements under CSRD.
Do I need special software to view an ESRS XBRL file?
No — like all inline XBRL, the file opens as a normal document in any web browser. The tags are embedded in the code and read by the systems processing the filing, not visible to someone simply viewing the report.