timeid

TimeID is a class of identifiers designed to encode the creation time of an object and to provide unique, sortable IDs. TimeIDs are often used in distributed systems and data stores to enable efficient ordering, indexing, and partitioning without requiring a separate timestamp field.

Typically, a timeID combines a timestamp portion with a suffix that guarantees uniqueness within the same time unit. The timestamp is usually the number of milliseconds or microseconds since an epoch, and the suffix may be random, counter-based, or derived from a node identifier. The encoding (for example base32, base64, or hexadecimal) is chosen to balance compactness with lexicographic sortable behavior.

Key properties include monotonicity (IDs created later compare greater), lexicographic sortability, and high scalability. Generation may rely on synchronized clocks; to mitigate clock skew, implementations often include a per-timestamp sequence component to preserve order within the same time unit.

Use cases include database keys, event logs, distributed messaging, and trace identifiers. TimeIDs are often discussed alongside similar schemes such as ULID and KSUID, which also emphasize time-based ordering and compact encodings. Limitations include potential privacy concerns from embedding timestamps and the need to manage clock synchronization and sequence state. Variants differ in encoding and time resolution; no single universal standard exists, but many projects adopt a time-based ID approach for sortable, scalable identifiers.