The boring generators that turned out to matter most

UUID (v4 and v7), ULID, Nano ID, MongoDB ObjectId, and an auto-increment sequence. The primary keys — technical identifiers no national registry issues but every record needs.

The detail worth stealing: any embedded timestamp derives from the seed, not the wall clock. A seeded UUID v7 is reproducible, which makes it better than a real random one for fixtures.

At the time this felt like housekeeping. It was the missing ingredient for the feature that came a few weeks later.