GUID V4 - Random-Based Identifier (Recommended)
GUID v4 is the most widely used random-based identifier. Learn about its structure, collision probability, advantages and why it is recommended for general-purpose applications.
How to Generate UUIDs in PostgreSQL
Generate UUIDs in PostgreSQL with gen_random_uuid() for v4-style values and uuidv7() on PostgreSQL 18 or newer when you want better index locality.
Recommendation: use UUID v4 when you want broad compatibility. Use UUID v7 when your PostgreSQL version supports it and you want better index locality.
How to generate UUID v4 in PostgreSQL
SELECT gen_random_uuid();This is commonly available through pgcrypto or newer PostgreSQL packaging that exposes the function directly.
How to generate UUID v7 in PostgreSQL
SELECT uuidv7();Check your PostgreSQL version first. uuidv7() is built in on PostgreSQL 18 and later, so older deployments still need an application-side fallback.
Native support notes
- PostgreSQL natively supports the UUID data type regardless of how values are generated.
- Generation functions and extension requirements vary by version.
uuidv7()is built in on PostgreSQL 18 and later.- Separate storage support from generation support when documenting UUID behavior.
Practical notes
- UUID v4 is easy to adopt and widely portable.
- UUID v7 can reduce index fragmentation compared with random inserts.
- See database performance and indexing before choosing a primary key strategy.
Frequently Asked Questions
UUID storage is native, but generation functions depend on version and installed extensions.
No.
uuidv7() is built in on PostgreSQL 18 and later, so verify the exact release you deploy before depending on it.Learn more
These articles expand on related concepts, formats and practical considerations.