UUIDバリデーター

UUID形式を検証・確認

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UUIDバリデーター の使い方

  1. 1入力フィールドに UUID を貼り付ける
  2. 2自動的に即座に検証される

UUIDバリデーター について

UUID バリデーターは UUID/GUID 識別子の有効性とフォーマットを検証するツールです。UUID のすべてのバージョン (v1-v5) をサポートします。

UUIDバリデーターの主な機能

  • 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

使用例

Validate a UUID v4 from an API response

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

入力

550e8400-e29b-41d4-a716-446655440000

出力

Valid UUID v4 ✓

Check a malformed UUID string

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

入力

550e8400-e29b-41d4-a716-44665544

出力

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

主な使用ケース

  • 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

トラブルシューティング

UUID is rejected despite looking correct

解決策

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

解決策

The version digit (the first character of the third group) must be 1–5. If the UUID was generated by a system using a non-standard method, it may not match any RFC 4122 version.

GUID from Windows appears invalid

解決策

Windows GUIDs are sometimes wrapped in curly braces ({550e8400-...}). Remove the curly braces before validating — the UUID inside is the actual value.

よくある質問

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 (Globally Unique Identifier) is Microsoft's term for UUID. They refer to the same 128-bit identifier format. Both follow the same RFC 4122 standard and are interchangeable in practice.

What is UUID v4?

UUID v4 is randomly generated, making it the most common type for new applications. It provides 122 bits of randomness, making collisions astronomically unlikely without requiring coordination between systems.

Is UUID v4 truly unique?

With 2^122 possible values, the probability of two random UUIDs colliding is negligibly small for any practical application. You would need to generate billions of UUIDs per second for centuries to encounter a collision.

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), and N is the variant digit (8, 9, a, or b for RFC 4122).

Is my data sent to a server?

No. All validation is performed locally in your browser using a regular expression check against the RFC 4122 pattern. Your UUIDs are never transmitted or stored.

Does it validate UUID nil values?

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