Common IDs workflows
An identifier can contain time information without being a reliable audit record. UUID v7 and ULID include millisecond timestamps; MongoDB ObjectId exposes seconds; Snowflake interpretation depends on the system’s epoch and bit layout. The time usually reflects when an ID was generated, which can differ from when a database row or business event was created.
Generate an identifier for a fixture
Choose UUID v4 for a random UUID or v7 when you need a UUID format that carries time. ULID offers another sortable representation. Check what your database and application libraries accept before switching formats.
- UUID v4 / v7 Generator — Bulk-generate UUID v7 and v4, and decode UUIDv7.
- ULID Generator — Generate ULIDs and decode their timestamps.
Choose a compact or deterministic identifier
Use NanoID for configurable random strings, KSUID for seconds-based sortable IDs, and UUID v5 when a namespace and name must always produce the same value. These formats have different entropy and ordering properties.
- NanoID Generator — Generate custom short IDs and estimate collision probability.
- KSUID Generator / Decoder — Generate and inspect 160-bit, time-sortable KSUIDs.
- UUID v5 Generator — Generate stable name-based UUIDs with DNS or custom namespaces.
- UUID v4 / v7 Generator — Bulk-generate UUID v7 and v4, and decode UUIDv7.
Inspect a platform or database ID
Select the correct Snowflake system before decoding its timestamp. For MongoDB, inspect the ObjectId’s timestamp rather than treating the full hexadecimal value as a Unix timestamp.
- Snowflake ID Decoder — Convert Discord and Twitter/X Snowflake IDs to dates.
- ObjectId to Timestamp — Get the creation date hidden in a MongoDB ObjectId.
Sortable IDs reveal creation time
UUID v7, ULID, KSUID and Snowflake IDs encode when they were generated. Use a random format such as UUID v4 or NanoID when an identifier should not expose timing.
Frequently asked questions
Can I recover a creation date from every UUID?
No. UUID v4 is random and has no creation timestamp. UUID v7 contains a Unix timestamp; other time-based UUID versions use different layouts and epochs. Use the decoder only for the versions it supports.
Is an ID timestamp proof that an event happened then?
No. A client can generate an ID earlier, later or with a modified clock. Use authoritative event records when you need evidence of when an action occurred.
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