What counts as a user
Four definitions are in circulation, and the gap between them is wide enough to change the decision.
Named account. Every account that exists, whether or not it was opened this month. Simple to administer and simple to audit, and the definition most likely to charge you for people who have left, for test accounts nobody deleted, and for integrations that log in as a user.
Concurrent user. The count of sessions at the same moment. Cheap on paper for shift-based, part-time or occasional populations, where four hundred people share sixty simultaneous seats. The bill is small and the peak is the risk: the day everyone opens the same document is the day the licence is short.
Active member. An enabled account counted as a member of the workspace. Our documentation defines seat usage this way — the number of active company members in a tenant, with each active member occupying one seat — so a seat is consumed by a person who is a member, not by an editor session. Two hundred concurrent editors and two hundred members are different numbers, and only one of them is on the licence.
Occasional and external. Clients, reviewers, suppliers, auditors, anyone outside the organisation who opens a document to comment on it. This definition decides a document platform bill more often than any other, because documents are the artefact organisations share outward.
Service accounts are the category nobody asks about until the true-up: API credentials, automation, scheduled jobs, migration scripts. Ask whether an integration that reads documents needs a seat, and get the answer into the contract rather than an email.
Four hundred employees and nine hundred external collaborators is a different invoice when guests are free than when every guest is a named user — same software, same headcount.
The count of named users, not the size of the server, is the number you will actually pay for.
So do not verify the word “user”. Verify the sentence: what counts as one, what happens when someone leaves, whether disabled accounts are charged, whether guests and service accounts are charged, and whether the count is measured on the day you sign or the day the vendor looks.