Opt-in and buyer-driven, not universal. Exchange is decentralised via private operators (Finbite, Telema, Unifiedpost, e-arveldaja) with roaming plus Peppol. Public sector entities are registered recipients by default.
PRIMARY/SECONDARY CONFLICT — the sharpest one in this set. Sovos, Marosa, EDICOM and VATupdate all present 'Estonia mandates B2B from 2027' as near-settled. The Estonian Ministry of Finance's own guidance page, updated 12 January 2026, describes ONLY the opt-in 2025 regime and makes no mention of a 2027 mandate; no Riigikogu bill or Riigi Teataja publication could be located. DO NOT PUBLISH 2027 AS A DATE. Separately, the live buyer's right is easy to miss because it is triggered by a flag on the COUNTERPARTY's registry entry, not by your own status.
2 of 4 are primary sources. Mandate dates move — treat this page as a starting point and confirm against the primary source before committing a plan.
A page is a starting point. A scoped analysis gives you the specification, the mapping and the effort — in weeks, not quarters.
