UUIDv7's Ordering, Timestamp Myths Exposed

UUIDv7 is best treated as a rough locality hint—not a trustworthy event-ordering system or security token.

• –RFC 9562 permits implementations to alter timestamps or add counters to preserve monotonicity, trading timestamp accuracy for ordering.
• –Same-millisecond generation, distributed clock skew, restarts, and backward clock jumps can all produce surprising order.
• –Embedded millisecond timestamps leak creation metadata and make identifiers easier to guess than UUIDv4.
• –Applications needing auditability or causal order should store explicit timestamps or sequence fields.
• –Developers should evaluate each UUIDv7 library’s clock, counter, persistence, and predictability guarantees.