Quick answer

Compare random UUID v4 identifiers with time-ordered UUID v7 values for APIs, databases, and distributed systems.

Random versus time ordered

Version 4 fills most bits with randomness. Version 7 places a Unix-millisecond timestamp first and uses random bits for the remainder, producing values that sort roughly by creation time.

Database considerations

Random inserts can scatter index pages. Time-ordered values usually improve locality, though exact performance depends on the database, storage engine, key type, and workload.

Privacy considerations

UUID v7 reveals approximate creation time. Use UUID v4 when that timestamp leakage is undesirable, and never treat either format as a secret.

Next step: Use the related browser tool to apply these ideas and verify the result in its destination system.