Sourcing
Guides start from primary sources where they exist: the European Commission, OpenPeppol, and national tax or procurement authorities. Secondary summaries are not treated as authority for an obligation, format or date.
Dates
Each guide shows a published date and an evidence-checked date. A date is the date the evidence was checked, not a claim that a rule is unchanged after that date.
No invented figures
This site publishes no invented fees, adoption rates, deadlines or case studies. Worked examples use round numbers and are labelled as illustrations.
Corrections
Errors are corrected on the corrections page, with what changed and why, rather than silently edited away.
Independence
No vendor, product or network is recommended. The site does not generate leads and does not run a directory.