UUID / GUID Validator: Validate Format, Version & Structure Instantly

You’ve received a UUID from an API. You’re importing data with GUIDs. You’re debugging why a database query isn’t finding a record. You suspect the UUID format might be wrong.

How do you know if a UUID or GUID is valid?

Invalid UUIDs can break API integrations, cause database errors, and create hard-to-debug issues. But manually checking UUID format is tedious — counting characters, verifying hex digits, checking hyphens, and ensuring proper structure.

The Tooladex UUID / GUID Validator solves this instantly: paste UUIDs or GUIDs (one or many), get immediate validation results, see detected versions, and identify format issues. All validation happens entirely in your browser — no server requests, complete privacy.

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🔍 Why Validate UUIDs and GUIDs?

Invalid UUIDs cause real problems:

• API Failures: Invalid UUIDs in API requests return 400 errors
• Database Errors: Invalid UUIDs cause SQL errors and failed queries
• Data Corruption: Invalid UUIDs can silently corrupt data
• Debugging Nightmares: Format issues are hard to spot in logs
• Integration Problems: Invalid UUIDs break system integrations

Validation catches these issues before they become problems.

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🧪 What Is UUID / GUID Validation?

UUID/GUID validation checks whether a string conforms to the RFC 4122 format:

• Correct length: 32 hexadecimal characters (128 bits)
• Proper grouping: Five groups separated by hyphens (8-4-4-4-12)
• Valid characters: Only hexadecimal digits (0-9, a-f, A-F)
• Version detection: Identifies UUID version (1-8) when valid
• Variant bits: Verifies variant bits are correctly set
• Format compliance: Ensures structure matches RFC 4122

Supported Formats

The validator accepts UUIDs/GUIDs in multiple formats:

• Standard format: 550e8400-e29b-41d4-a716-446655440000
• Without hyphens: 550e8400e29b41d4a716446655440000
• GUID format (with braces): {550e8400-e29b-41d4-a716-446655440000}
• Uppercase or lowercase: Case-insensitive validation

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🚨 Common UUID Validation Scenarios

Scenario 1: API Response Validation

You receive UUIDs from an API and need to verify they’re valid before processing:

API Response:
{
  "userId": "550e8400-e29b-41d4-a716-446655440000",
  "orderId": "6ba7b810-9dad-11d1-80b4-00c04fd430c8",
  "sessionId": "invalid-uuid-format"
}

Problem: One UUID is invalid, but which one?

Solution: Paste all UUIDs into the validator. It immediately identifies "invalid-uuid-format" as invalid and shows the exact error.

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Scenario 2: Database Import Validation

You’re importing a CSV file with UUIDs and want to ensure all UUIDs are valid before inserting:

id,name,email
550e8400-e29b-41d4-a716-446655440000,John,john@example.com
6ba7b810-9dad-11d1-80b4-00c04fd430c8,Jane,jane@example.com
550e8400-e29b-41d4-a716-44665544000,Bob,bob@example.com

Problem: One UUID is too short (missing a character).

Solution: Copy all UUIDs from the CSV, paste into the validator. It identifies the invalid UUID and shows “Too short (UUIDs must be 32 hexadecimal characters)“.

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Scenario 3: Log File Debugging

Your application logs show UUIDs, but some operations are failing. You suspect invalid UUIDs:

[2026-02-19 10:00:00] Processing user: 550e8400-e29b-41d4-a716-446655440000
[2026-02-19 10:00:01] Processing user: 550e8400-e29b-41d4-a716-44665544000
[2026-02-19 10:00:02] ERROR: Invalid UUID format

Problem: One UUID in the logs is invalid, causing the error.

Solution: Copy UUIDs from logs, validate them. The validator immediately shows which UUID is invalid and why.

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Scenario 4: Form Input Validation

Users enter UUIDs in a web form, and you need to validate before submission:

User Input: "550e8400-e29b-41d4-a716-446655440000"

Problem: Is this a valid UUID? Should you accept it?

Solution: Validate the input. The validator confirms it’s valid, shows the normalized format, and detects the version.

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Scenario 5: Batch Data Cleaning

You have a list of UUIDs from multiple sources and need to:

1. Identify invalid UUIDs
2. Normalize valid UUIDs to standard format
3. Extract only valid UUIDs for processing

Solution: Paste all UUIDs into the validator. It shows:

• Which UUIDs are valid
• Which UUIDs are invalid (with error messages)
• Normalized versions of valid UUIDs
• Option to copy only valid UUIDs

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🛠️ How UUID Validation Works

Format Validation

The validator checks:

1. Length: Exactly 32 hexadecimal characters (excluding hyphens/braces)
2. Structure: Proper grouping (8-4-4-4-12) when hyphens are present
3. Characters: Only valid hexadecimal digits (0-9, a-f, A-F)
4. Hyphens: Correct placement in standard format
5. Braces: Proper GUID format with braces (if present)

Version Detection

For valid UUIDs, the validator detects the version:

• Version 1: Time-based UUID
• Version 2: DCE security UUID
• Version 3: Name-based (MD5)
• Version 4: Random UUID (most common)
• Version 5: Name-based (SHA-1)
• Versions 6-8: Newer UUID versions

The version is extracted from the 13th character of the UUID.

Normalization

Valid UUIDs are normalized to standard format:

• Lowercase hexadecimal digits
• Standard hyphen grouping: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
• Removes braces (for GUID format)
• Adds hyphens (for format without hyphens)

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🚀 Tooladex UUID / GUID Validator Features

⭐ 1. Instant Validation

Paste UUIDs and get immediate validation results. No delays, no server round-trips.

⭐ 2. Batch Validation

Validate multiple UUIDs at once. Paste UUIDs separated by newlines or commas — the validator processes all of them.

⭐ 3. Detailed Error Messages

Invalid UUIDs show specific error messages:

• “Too short” — missing characters
• “Too long” — extra characters
• “Invalid characters” — non-hexadecimal characters
• “Invalid format” — structure doesn’t match UUID format

⭐ 4. Version Detection

Valid UUIDs show their detected version (1-8), helping you understand UUID type.

⭐ 5. Format Detection

Identifies UUID format:

• Standard format (with hyphens)
• Without hyphens
• GUID format (with braces)

⭐ 6. Normalization

Shows normalized version of valid UUIDs in standard lowercase format with hyphens.

⭐ 7. Copy Valid UUIDs

Copy all valid UUIDs at once with one click. Perfect for data cleaning and filtering.

⭐ 8. Privacy-First

All validation happens entirely in your browser. Your UUIDs never leave your device.

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📋 Practical Examples

Example 1: API Testing

// Test UUIDs from API responses
const apiUuids = [
  "550e8400-e29b-41d4-a716-446655440000",
  "6ba7b810-9dad-11d1-80b4-00c04fd430c8",
  "invalid-uuid"
];

// Validate before processing
// Use Tooladex UUID Validator to check all UUIDs
// Result: First two are valid, third is invalid

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Example 2: Database Query Debugging

-- Query failing? Validate the UUID first
SELECT * FROM users WHERE id = '550e8400-e29b-41d4-a716-44665544000';

-- Validator shows: "Too short (UUIDs must be 32 hexadecimal characters)"
-- Fix: Add missing character
SELECT * FROM users WHERE id = '550e8400-e29b-41d4-a716-446655440000';

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Example 3: Data Import Validation

# Python: Validate UUIDs before database import
import uuid

user_ids = [
    "550e8400-e29b-41d4-a716-446655440000",
    "6ba7b810-9dad-11d1-80b4-00c04fd430c8",
    "invalid"
]

# Use Tooladex Validator to check all UUIDs first
# Then validate in code:
for user_id in user_ids:
    try:
        uuid.UUID(user_id)
        print(f"Valid: {user_id}")
    except ValueError:
        print(f"Invalid: {user_id}")

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Example 4: Log Analysis

# Extract UUIDs from logs
grep "user_id" application.log | awk '{print $3}'

# Paste into Tooladex Validator
# Identifies which UUIDs are invalid
# Shows normalized versions of valid UUIDs

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🎯 Best Practices

Validate Before Processing

Always validate UUIDs before:

• Database operations
• API requests
• Data imports
• File processing

Use Batch Validation

When working with multiple UUIDs, validate them all at once. The Tooladex validator processes batches efficiently.

Normalize UUIDs

Use normalized UUIDs (standard format) for consistency:

• Database storage
• API responses
• Logging
• Comparisons

Check Version When Needed

If your application requires specific UUID versions (e.g., v4 for random UUIDs), use version detection to verify.

Validate User Input

Always validate UUIDs entered by users in forms or APIs. Invalid UUIDs should be rejected with clear error messages.

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❓ Frequently Asked Questions

What makes a UUID invalid?

A UUID is invalid if it:

• Doesn’t have exactly 32 hexadecimal characters
• Contains invalid characters (non-hexadecimal)
• Has incorrect structure (wrong hyphen placement)
• Is too short or too long
• Doesn’t match RFC 4122 format

Can I validate UUIDs without hyphens?

Yes! The validator accepts UUIDs in multiple formats:

• With hyphens: 550e8400-e29b-41d4-a716-446655440000
• Without hyphens: 550e8400e29b41d4a716446655440000
• With braces: {550e8400-e29b-41d4-a716-446655440000}

Does the validator check UUID version?

Yes! For valid UUIDs, the validator detects and displays the version (1-8). This helps you understand UUID type and ensure you’re using the correct version for your use case.

Can I validate multiple UUIDs at once?

Yes! Paste multiple UUIDs separated by newlines or commas. The validator processes all of them and shows results for each UUID.

What’s the difference between UUID and GUID validation?

UUID and GUID are the same format (RFC 4122). The validator handles both. GUIDs are often shown with braces, which the validator accepts and normalizes.

Is my data sent to a server?

No! All validation happens entirely in your browser. Your UUIDs never leave your device — complete privacy and security.

Can I copy only valid UUIDs?

Yes! The validator has a “Copy Valid” button that copies all valid UUIDs at once, making it easy to filter out invalid ones.

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🎉 Try the Tooladex UUID / GUID Validator

The Tooladex UUID / GUID Validator helps you:

• Validate UUIDs and GUIDs instantly
• Check format compliance with RFC 4122
• Detect UUID versions (1-8)
• Identify invalid UUIDs with detailed error messages
• Normalize UUIDs to standard format
• Validate multiple UUIDs at once (batch validation)
• Copy valid UUIDs for data cleaning
• Ensure data quality in APIs, databases, and applications

Whether you’re testing APIs, debugging database queries, importing data, analyzing logs, or validating user input, this tool makes UUID validation simple and efficient.

✔ Instant validation
✔ Batch validation (multiple UUIDs)
✔ Detailed error messages
✔ Version detection
✔ Format normalization
✔ Copy valid UUIDs
✔ 100% client-side — complete privacy
✔ Supports all UUID/GUID formats

Try it now — and ensure your UUIDs and GUIDs are valid before they cause problems.