UUID v4 - 128-bit random ID. Universal standard. Use when you need a truly random, unordered identifier.
UUID v7 - same format as v4 but starts with a Unix timestamp. Time-sortable, great for database primary keys.
NanoID - shorter URL-friendly ID (21 chars). Use for URL slugs, short links, tokens where space matters.
ULID - 26-char time-sortable ID (Crockford base32). Readable, sortable, no hyphens. Good for logs and events.
Snowflake - 64-bit numeric ID popularized by Twitter. Timestamp + machine + sequence. Good for high-throughput distributed systems.
All IDs are generated with crypto.getRandomValues - cryptographically secure.