The UUID Validator helps developers verify the integrity and version of UUID strings — detecting v1 through v5, RFC 4122 compliance, and format issues. All validation runs 100% locally in your browser. Whether you are debugging a database error, verifying an API response, or setting up a distributed system, knowing the exact UUID version and format helps you identify issues fast.
What is a UUID?
A UUID is a 128-bit number in 8-4-4-4-12 format with 32 hex digits. Version 4 (random) is most common. Version 1 uses MAC address + time. UUIDs are standardized by the Open Software Foundation (OSF) as part of the Distributed Computing Environment (DCE).
How to Use
- 1Paste UUID: Copy your UUID string into the input field.
- 2Validate instantly: Click "Validate UUID" or press Enter.
- 3Review results: See status, version (v1-v5), and variant (RFC 4122, GUID).
- 4Debug errors: Invalid UUIDs show common issues like missing hyphens or wrong character count.
Validation Logic
Uses regex matching for structure: /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i. Version is determined by the 13th character (first digit of third group). Variant is analyzed from the 17th character's bit patterns — distinguishing RFC 4122 from Microsoft GUIDs and legacy variants.
Why Use This Tool
UUIDs are everywhere in modern software development — database primary keys, session identifiers, API resource IDs, and more. A single invalid UUID can break an entire workflow. This tool gives you instant feedback on UUID validity, version detection, and RFC compliance without needing to remember regex patterns or bit masks.
Tips for Developers
Always include hyphens in the standard 8-4-4-4-12 format. Check the version digit (13th character) to understand how the UUID was generated. Use v4 for random IDs and v5 for deterministic naming. The NIL UUID (all zeros) is valid but should not be used as a real identifier.
Frequently Asked Questions
Yes, 100% free with no hidden costs, subscriptions, or limits.
Absolutely. All processing happens locally in your browser. Never uploaded.
All standard versions: v1, v2, v3, v4, and v5, plus the special NIL UUID.
GUID is Microsoft's implementation of the UUID standard. For practical purposes, they're identical.
Most programming languages have built-in UUID generation. JavaScript uses crypto.randomUUID(), Python uses uuid.uuid4().
Wrong length, non-hex characters, incorrect hyphen placement, or unrecognized version/variant bits.
Yes, hexadecimal digits A-F are valid in UUIDs. The validator is case-insensitive.
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