Cryptographically Secure UUID v4, UUID v7, NanoID & CUID Generation
All identifiers are generated locally using your browser's cryptographically secure random number generator (crypto.randomUUID() and crypto.getRandomValues()). RFC 9562 UUID v7 embeds a 48-bit big-endian millisecond Unix timestamp for B-tree index locality in relational databases, while NanoID and CUID offer compact, URL-safe alternatives.
RFC 9562 UUID v7 & v4
Generate random 122-bit UUID v4 strings or monotonic time-ordered UUID v7 identifiers that prevent B-tree page fragmentation in PostgreSQL, MySQL/InnoDB, and SQLite primary keys.
UUID v7 Timestamp Extraction
Paste any UUID v7 string into the inspector to verify its version nibble (7) and variant bits (10xx) and decode the exact 48-bit UTC millisecond creation timestamp.
Custom NanoID & CUID
Configure custom NanoID lengths (4–128 chars) and alphabets with unbiased rejection sampling, or generate collision-resistant CUID strings for client-side state stores.
Frequently Asked Questions
Why is UUID v7 preferred over UUID v4 for database primary keys?
Because UUID v4 is completely random, every new row insertion targets a random page in a B-tree index, causing frequent page splits and buffer pool churn on large tables. UUID v7 prefixes the identifier with a 48-bit millisecond Unix timestamp so newly generated IDs append sequentially at the end of the index.
Can I strip hyphens or output uppercase hex UUIDs?
Yes. Check UPPERCASE or No hyphens in the toolbar to emit compact 32-character hex strings or uppercase GUID representations.