KSUID Generator and Decoder

Generate K-sortable unique IDs (KSUID) and decode the timestamp and payload from an existing one.

What this does

Generate KSUID values (K-Sortable Unique IDs, originally from Segment) in bulk, or paste one to read its timestamp and payload.

Layout

4 bytes: seconds since the KSUID epoch, 2014-05-13T16:53:20Z (Unix time 1400000000).
16 bytes: random payload from the browser's secure random source.
The 20 bytes are written as 27 base62 characters (0-9A-Za-z), padded with leading zeros.

Base62 with a fixed width keeps KSUIDs sortable as plain strings, so they order by creation second in a database index.

Example

0ujtsYcgvSTl8PAuAdqWYSMnLOv decodes to 2017-10-10T04:00:47.000Zwith payload B5A1CD34B5F99D1154FB6853345C9735.

Limits

The timestamp has one-second resolution and a 32-bit range, which runs out in the year 2150. The millisecond variant (KSUIDMS) is not supported.

Privacy

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