RESTful APIs sometimes expose resources via UUID-based endpoints, e.g., GET /api/v1/orders/5a82f65b-9a1b-41b1-af1b-c9df802d15db . This has the benefit of obfuscating sequential information (unlike /orders/1234 ) and scaling horizontally because ID generation requires no coordination.
ULID (Universally Unique Lexicographically Sortable Identifier) 36 characters (with hyphens) 26 characters Variable (Default: 21) Character Set Hexadecimal ( 0-9 , a-f ) Base32 (Case-insensitive) URL-safe Base64 symbols Sortability Purely random; indexing degrades database performance Chronologically sortable (embedded timestamp) Purely random Primary Advantage Ubiquitous industry standard native to most environments Excellent for ordered database indexing Compact footprint optimized for web URLs
: A reference number for a digital purchase or support ticket.
: Systems can generate them offline without consulting a primary server. 5a82f65b-9a1b-41b1-af1b-c9df802d15db
The version number is located in the most significant 4 bits of the Time High section (the 4 in 41b1 ).
Create keys offline without checking a master server database.
5a82f65b-9a1b-41b1-af1b-c9df802d15db
To understand the generation source of this specific identifier, we must examine the specific bits allocated for version and variant information.
is a Globally Unique Identifier (GUID), also known as a Universally Unique Identifier (UUID), representing a 128-bit value used to uniquely identify resources in modern computing.
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Mobile applications frequently need to create data while offline. Because UUID generation happens entirely on the local device client, an offline app can generate a unique string, save the record locally, and upload it to the main cloud database later without risking duplicates. The Probability of a Collision
possible combinations, which equals roughly variants.
Below is an exploration of how identifiers like this—and specifically the segments within this one—function in the world of technology. Understanding UUIDs: The Architecture of Digital Identity Try again later.
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