MiCA whitepaper guide
MiCA iXBRL filing: the ESMA taxonomy and validation
Since 23 December 2025, a MiCA whitepaper is not a PDF. ITS (EU) 2024/2984 requires it to be a single Inline XBRL (iXBRL) XHTML document: it reads as normal narrative to a human while carrying machine-readable XBRL tags on each reportable data point, tagged against the ESMA MiCA taxonomy. Competent authorities and ESMA ingest the structured data automatically, and PDF-only submissions no longer meet the requirement. The taxonomy defines existence and value assertions that the instance must satisfy, and a valid Legal Entity Identifier (LEI) is a mandatory tagged field — without one the instance cannot be filed.
Last reviewed: 6 July 2026
What Inline XBRL is
XBRL (eXtensible Business Reporting Language) is a standard for tagging data so machines can read it. Inline XBRL, or iXBRL, embeds those tags inside a human-readable XHTML document — so a single file is both the narrative a person reads and the structured data a regulator ingests.
For MiCA, ITS (EU) 2024/2984 sets the forms, formats and templates for all three whitepaper types (OTHR, ART and EMT). The 'other' crypto-asset uses the OTHR template. The tags reference the ESMA MiCA XBRL taxonomy (version 1.0 published 5 August 2025), which maps the Annex I content into structured tables. Element labels do not always match the ITS template field names one-to-one, so mapping Annex I fields to taxonomy elements is a deliberate task, not a copy.
What the format requires
| Requirement | Detail | Legal basis |
|---|---|---|
| Single XHTML container | The whitepaper is one self-contained XHTML file, not a multi-file bundle. | ITS (EU) 2024/2984 |
| Inline XBRL tagging | Tags are embedded inline in the XHTML; the human-readable narrative is preserved. | ITS (EU) 2024/2984 |
| ESMA MiCA taxonomy | Tags reference the ESMA MiCA XBRL taxonomy (v1.0, 5 August 2025); pin the version and re-validate on updates. | ESMA taxonomy |
| Validation assertions | The instance must satisfy the taxonomy's existence assertions and value assertions before it can be filed. | ESMA reporting manual |
Validation and common failure classes
A compliant instance must pass the taxonomy's assertions before it can be filed. Validation failures group into a few recurring classes — a validator surfaces each as a human-readable fix.
Missing mandatory element (existence assertion)
A required data point is not tagged at all — a missing Annex I field or mandatory statement. The taxonomy's existence assertions fail when a reportable element the OTHR template requires is absent.
Invalid value (value assertion)
A tagged value breaks a rule the taxonomy enforces — a malformed LEI, a date outside an allowed range, a figure that must reconcile with another, or an enumerated field with a value outside its allowed set.
Missing or invalid LEI
The offeror or issuer LEI is absent or fails its checksum. The LEI is a mandatory tagged field mirroring Annex I Part A — no LEI, no valid instance.
Structural / container errors
The output is not a single self-contained XHTML file, or the inline tags are malformed, so the instance is not machine-readable at all.
Test your iXBRL file against the ESMA taxonomy for free before you file with the competent authority.
Validate your whitepaper fileThe LEI requirement
A valid Legal Entity Identifier for the offeror or issuer is required and is a tagged field in the taxonomy, mirroring Annex I Part A. Without an LEI the instance cannot be validly produced or filed, so LEI capture and checksum validation belong early in the flow — treat 'you need an LEI first' as a pre-flight gate.
Tokenpaper produces the whitepaper as validated Inline XBRL against the ESMA taxonomy and blocks export on a failed assertion, with plain-language fixes. Software, not legal advice; the issuer stays liable under Article 15. See Tokenpaper.
Frequently asked questions
Does a MiCA whitepaper have to be in iXBRL?
Yes, since 23 December 2025. ITS (EU) 2024/2984 requires a MiCA whitepaper to be a single Inline XBRL (iXBRL) XHTML document tagged against the ESMA MiCA taxonomy. A PDF-only submission no longer meets the format requirement, and exchanges have de-listed tokens whose whitepapers were not compliant.
What is the ESMA MiCA taxonomy?
It is the XBRL tagging framework ESMA publishes for MiCA whitepapers (version 1.0 published 5 August 2025). It maps the Article 6 / Annex I content into structured tables and defines the existence and value assertions an iXBRL instance must satisfy. The 'other' crypto-asset uses the OTHR template.
Why does a MiCA iXBRL filing fail validation?
Most failures fall into a few classes: a missing mandatory element (an existence-assertion failure — a required Annex I field or statement not tagged), an invalid value (a value-assertion failure — a malformed LEI, an out-of-range date, or an enumerated field with a bad value), a missing or invalid LEI, or a structural error where the output is not a single well-formed XHTML file.
Do I need an LEI to file a MiCA whitepaper?
Yes. A valid Legal Entity Identifier for the offeror or issuer is a mandatory tagged field in the ESMA taxonomy, mirroring Annex I Part A. Without an LEI the iXBRL instance cannot be validly produced or filed, so obtaining one is effectively a pre-flight step.