UUID Validator

Validate and inspect UUID format

Developer Tools

How to Use UUID Validator

  1. 1Paste one or more UUIDs (one per line)
  2. 2See validation results instantly

About UUID Validator

UUID Validator checks whether a given string is a properly formatted UUID (Universally Unique Identifier) or GUID (Globally Unique Identifier) and identifies its version. UUIDs are used everywhere as unique keys in databases, APIs, distributed systems, and message queues.

A valid UUID follows the pattern xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx where M indicates the version (1–5) and N indicates the variant. The validator instantly checks the format, extracts the version number, and confirms RFC 4122 compliance.

All validation runs in your browser with no server required. Paste one or multiple UUIDs (one per line) and get instant validation results for each.

Key Features of UUID Validator

  • Validate any UUID or GUID against the RFC 4122 standard format
  • Detect UUID version (v1, v3, v4, v5)
  • Clear pass/fail result for each UUID validated
  • Supports bulk validation — one UUID per line
  • Accepts both uppercase and lowercase UUIDs
  • Works entirely in-browser — no server requests
  • Instant results with no submit delay
  • Explains why an invalid UUID fails the check

Examples

Validate a UUID v4 from an API response

Confirm that an ID returned by an API is a properly formatted UUID v4.

Input

550e8400-e29b-41d4-a716-446655440000

Output

Valid UUID v4 ✓

Check a malformed UUID string

Identify why a UUID-like string from a database export is invalid.

Input

550e8400-e29b-41d4-a716-44665544

Output

Invalid UUID — incorrect length (missing characters in last section)

Common Use Cases

  • Validating UUIDs in API request payloads before processing them
  • Checking UUID format in database import files before bulk insertion
  • Verifying UUID generation in unit tests and integration tests
  • Debugging API errors caused by malformed UUID parameters
  • Confirming that a GUID from a legacy Windows system is RFC 4122-compliant
  • Batch-checking a list of UUIDs from a data export for format compliance

Troubleshooting

UUID is rejected despite looking correct

Solution

Check for invisible characters, extra whitespace, or missing hyphens. A valid UUID must have exactly 5 groups separated by hyphens in the pattern 8-4-4-4-12 characters.

UUID version is shown as unknown

Solution

The version digit must be 1–5. If generated by a non-standard method, it may not match any RFC 4122 version.

GUID from Windows appears invalid

Solution

Windows GUIDs are sometimes wrapped in curly braces ({550e8400-...}). Remove the curly braces before validating.

Frequently Asked Questions

What UUID versions are supported?

The validator detects UUID versions 1 (time-based), 3 (name-based MD5), 4 (random), and 5 (name-based SHA-1) in standard RFC 4122 hyphenated format.

What is the difference between a UUID and a GUID?

GUID is Microsoft's term for UUID. They refer to the same 128-bit identifier format. Both follow RFC 4122 and are interchangeable.

What is UUID v4?

UUID v4 is randomly generated, making it the most common type for new applications. It provides 122 bits of randomness.

Is UUID v4 truly unique?

With 2^122 possible values, the probability of two random UUIDs colliding is negligibly small for any practical application.

Can I validate UUIDs in bulk?

Yes. Paste one UUID per line and the tool validates all of them, showing pass/fail results for each entry.

What format does a valid UUID follow?

A valid UUID follows the pattern xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx, where x is a hexadecimal digit, M is the version digit (1–5).

Is my data sent to a server?

No. All validation is performed locally using a regular expression check. Your UUIDs are never transmitted or stored.

Does it validate UUID nil values?

The nil UUID (00000000-0000-0000-0000-000000000000) is technically valid per RFC 4122. It is used as a placeholder in some systems.