UUID Generator: What is UUID and How to Generate Unique Identifiers
A UUID (Universally Unique Identifier) generator creates IDs that are effectively unique across systems—no central server required. It's the standard solution for database keys and API identifiers.
What Makes a UUID Unique
UUIDs combine random bits with version and variant fields. Version 4 UUIDs use 122 random bits, making collisions vanishingly unlikely even across billions of IDs.
When to Use UUIDs
Use UUIDs for records that sync across databases, public API identifiers, and session tokens. They work offline and merge cleanly between systems.
Versions at a Glance
Version 4 is fully random; version 1 embeds a timestamp and node id. Choose v4 for most applications unless you need time-ordering, in which case v7 is a modern choice.
Generating in Bulk
Generate as many IDs as you need at once and paste them into a file or spreadsheet. Consistent lowercase hyphenated format keeps your data uniform.
Storing and Indexing UUIDs
Random UUIDs perform poorly as database primary keys on large tables because inserts land in scattered pages. Storing them as binary or using ordered UUID variants keeps indexes efficient.
For analytics and logs, generate the ID at write time and keep it in a dedicated indexed column. Uniform lowercase format also makes joins and debugging predictable.
How to Generate UUIDs
- Choose the UUID version that fits your case—v4 random for most, v7 if you want time order.
- Set the count you need, from one to hundreds.
- Copy the list in lowercase hyphenated form into your database or config.
Generate at write time rather than reusing stored IDs, and keep them in a dedicated indexed column for fast lookups.
Quick tip: never generate UUIDs by hand or reuse IDs across environments. Always generate fresh ones with the tool at the moment you create the record.