All UUID guides
Newest first, 12 to a page. Each one names the runtime its outputs came from.
UUID Text Forms — Seven Spellings Across Five Parsers
Seven spellings of one UUID through two standard libraries: Python and .NET agree on four and disagree on three, in both directions.
UUID v7 Monotonicity — Same-Millisecond IDs Sort Wrong
v7 sorts by time only across milliseconds — inside one, 50.2% of adjacent pairs came back reversed.
UUID vs NanoID: Shorter and Higher Entropy
21 characters at 126 bits against 36 at 122 — NanoID wins on both, and gives up the ecosystem.
UUID vs MongoDB ObjectId: 12 Bytes Against 16
12 bytes against 16: what each structure spends its bits on, and when to store a UUID in MongoDB.
Is a UUID Secure? Six Ways the Assumption Breaks
Is a UUID secure? Guessability, what each version leaks, and why an identifier is not a credential.
UUID vs Auto-Increment: Which Primary Key Should You Use?
8-byte integer versus 16-byte UUID: storage, enumeration risk, offline generation, and how v7 narrowed the gap.
UUID in C#: Guid.NewGuid, CreateVersion7 & the Byte-Order Trap
Guid.NewGuid() for v4 and .NET 9's Guid.CreateVersion7(), the missing v3/v5 support, Guid.Empty vs null, and the byte round-trip that corrupts silently.
UUID Decoder — Check Version, Variant & Extract the Timestamp
Paste a UUID to read its version and variant, recover the creation time from v1, v6 and v7, inspect the node field and see the per-version byte layout.
UUID in MySQL: BINARY(16), UUID_TO_BIN & the Swap Flag
BINARY(16) storage, what UUID_TO_BIN's swap flag really does, why MySQL's UUID() is v1, and InnoDB clustered-index cost.
How to Generate a UUID in Go (google/uuid, v7 & Gotchas)
google/uuid vs gofrs/uuid, generating v4 and v7, the New() panic trap and the silent zero-value Nil UUID.
UUID Collision Probability — The Real Numbers + Calculator
How likely a UUID collision really is, with the birthday-problem maths and an interactive calculator for v4, v7 and ULID.
How to Generate a UUID in Java (randomUUID, v5, v7 & JPA)
UUID.randomUUID(), the nameUUIDFromBytes v3-only trap, v7 libraries and JPA primary keys.