A TTL index deletes documents silently when a date passes. Retention of records needs holds, proof, content deletion and a stub. Here is the difference, with code.

Every few months I meet a document platform where "retention" is implemented like this:

db . documents . createIndex ({ " lifecycle.retention.dispositionDue " : 1 }, { expireAfterSeconds : 0 })

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One line, done. Documents disappear when their disposition date passes. It even sounds like records management.

It is not, and the gap between the two is the gap between a platform that can answer an auditor and one that cannot. This post goes through what a TTL index actually does, operationally, and what a disposition run must do instead.…