XBRL Digital Tagging
From 2026, every CSRD sustainability report must be machine-readable using XBRL tags. This is not optional. Reports that are not properly tagged will be rejected by regulators and cannot be accessed via the European Single Access Point (ESAP).
From 2026, every CSRD sustainability report must be machine-readable using XBRL tags. XBRL (eXtensible Business Reporting Language) is a global standard for machine-readable financial and sustainability data.
What XBRL tagging means in practice
XBRL (eXtensible Business Reporting Language) is a global standard for machine-readable financial and sustainability data. Inline XBRL (iXBRL) embeds machine-readable tags directly into human-readable HTML documents — you produce one document that serves both purposes.
For CSRD, every required quantitative and qualitative datapoint must be tagged using the EFRAG ESRS XBRL Taxonomy. This allows regulators, investors and data providers to extract, compare and analyse sustainability data automatically — without manual re-entry.
The EFRAG ESRS XBRL Taxonomy
EFRAG published the first ESRS XBRL Taxonomy in 2024. It covers all datapoints across all 12 ESRS standards. The taxonomy is updated annually as ESRS standards evolve — always use the taxonomy version corresponding to your reporting year.
Key taxonomy statistics: ESRS 2 has 89 tagged datapoints. ESRS E1 has 198 tagged datapoints. ESRS S1 has 134 tagged datapoints. Total across all standards exceeds 1,000 tagged datapoints for a full reporter.
How to produce an XBRL-tagged CSRD report
Three approaches exist. First — specialist software: dedicated ESG reporting platforms like ESGMaster generate XBRL-tagged output automatically from your data. This is the fastest and lowest-risk approach.
Second — manual tagging: using XBRL authoring software to tag a report written in Word or another tool. This is time-consuming and error-prone for reports with 1,000+ datapoints.
Third — auditor or consultant tagging: outsourcing the tagging to your assurance provider or a specialist firm. Expensive — typically €20,000–€80,000 for a full tagging engagement.
Frequently asked questions
Does my assurer check XBRL tags?
Yes. Limited assurance under CSRD covers the sustainability report including its digital format. Incorrectly tagged datapoints are assurance findings. Systematic tagging errors can result in a qualified assurance opinion.
What happens if my XBRL tags are wrong?
Regulators can require restatement. The report cannot be properly indexed on ESAP. Data aggregators will exclude your company from benchmarks. In serious cases, national regulators can impose fines for non-compliant filings.
When is XBRL mandatory for Wave 2 companies?
Wave 2 companies reporting under the Amended ESRS must produce XBRL-tagged reports from their first reporting year (FY2027, filed 2028). Allow 6 months of implementation time before first filing.
Can I tag only the quantitative datapoints?
No. Both quantitative (numbers) and qualitative (text) datapoints require tagging under the ESRS taxonomy. Text block tagging is mandatory for narrative disclosures.