ID generation looks like a small backend decision. In many systems, we simply add an id column, make it the primary key, and move on. But once the table grows, this decision can affect database performance, indexing, pagination, debugging, and how easily the system scales across services. The common choices are: UUIDv4 UUIDv7 Snowflake ID Each one solves the uniqueness problem, but they behave differently in real backend systems. UUIDv4: Simple, Random, and Widely Used UUIDv4 is one of the most commonly used ID formats in backend applications. A UUIDv4 looks like this: 550e8400-e29b-41d4-a716-446655440000 It is mostly random and can be generated independently by different services. That makes UUIDv4 useful when we want distributed ID generation without depending on a central database or ID generator. For example: user_id document_id payment_id report_request_id But UUIDv4 has one important problem. It is random. This matters when UUIDv4 is used as the primary key in a relational database like PostgreSQL.…