UUIDs, ULIDs and Sqids: A Practical Deep Dive

A thorough comparison of UUIDs (v4 and v7), ULIDs, and Sqids covering their generation models, sorting behavior, database storage trade-offs, and security implications. UUIDv4 offers opaque distributed IDs, UUIDv7 adds time-ordering while keeping UUID semantics, ULIDs provide compact lexicographically sortable 128-bit IDs, and Sqids generate reversible short public IDs from existing integers. The post includes PHP code examples using ramsey/uuid, robinvdvleuten/ulid, and the official Sqids package, plus a practical decision flow, database storage guidance (CHAR vs BINARY), and common mistakes like treating Sqids as encryption or relying on hard-to-guess IDs instead of proper authorization.