UUID Generator & Verifier
Generate and verify UUIDs v1, v4, v5, and v7. Create time-based, random, name-based, and sortable UUIDs for databases, APIs, and distributed systems with validation tools.
Generator Settings
Generated UUIDs
Generated UUIDs will appear here
Click "Generate UUIDs" to start
About UUID Versions
UUID v1: Uses timestamp and MAC address. Good for distributed systems needing time-ordering.
UUID v4: Completely random. Most common choice for general use.
UUID v5: Deterministic based on namespace and name. Same input always produces same UUID.
UUID v7: New standard (2024) with Unix timestamp. Best for databases needing sortable IDs.
About UUID Generator & Verifier
The UUID Generator & Verifier is a comprehensive development tool that creates and validates multiple UUID versions including v1 (timestamp-based), v4 (random), v5 (SHA-1 name-based), and v7 (time-ordered). Generate UUIDs in various formats (standard, uppercase, no-hyphens, braces, URN) and verify any UUID to identify its version. Perfect for distributed systems, database primary keys, and API resource identification with full RFC 4122 and RFC 9562 compliance.
Why use a UUID Generator & Verifier?
Different UUID versions serve different purposes: v1 for time-based ordering, v4 for complete randomness, v5 for deterministic generation from names, and v7 for sortable database keys. This tool provides all major UUID versions with instant validation, multiple output formats, batch generation (up to 100 UUIDs), and download capabilities. The built-in verifier identifies UUID versions and validates format compliance, ensuring your identifiers meet industry standards.
Who is it for?
Essential for software developers needing various UUID types, database architects requiring sortable v7 UUIDs for better indexing performance, and API developers implementing deterministic v5 UUIDs for consistent resource identification. Perfect for DevOps engineers managing distributed systems, full-stack developers handling user authentication, and system architects designing microservices that need guaranteed unique identifiers across multiple services.
How to use the tool
Select UUID version: v1 (timestamp), v4 (random), v5 (name-based), or v7 (sortable)
For v5, enter a name and select a namespace (DNS, URL, OID, X500, or custom UUID)
Choose output format: standard, uppercase, no-hyphens, braces, or URN format
Set the number of UUIDs to generate (1-100) and click Generate
Copy individual UUIDs or all at once, download as text file for batch operations
Use the built-in validator to verify and identify any UUID version
Frequently Asked Questions
How do I generate UUIDs (GUIDs) online?
Choose the UUID version (v4 random is most common) and how many to generate. The tool produces UUIDs instantly. Copy individual UUIDs or download a list. Runs entirely in your browser using `crypto.randomUUID()` (modern) or `crypto.getRandomValues()` (fallback). Useful for: database primary keys, distributed system IDs, anywhere you need a unique identifier with no central coordinator.
What is a UUID?
UUID (Universally Unique Identifier, also known as GUID — Globally Unique Identifier) is a 128-bit identifier defined by RFC 9562. Typical format: `f47ac10b-58cc-4372-a567-0e02b2c3d479` (32 hex digits split by hyphens into 8-4-4-4-12 groups). The probability of collision when generating random UUIDs is essentially zero (2^122 possibilities for v4 — more than atoms in the observable universe). UUIDs allow distributed systems to generate unique IDs without a central authority.
What are the different UUID versions?
Most common: **v4** (random, the default — generated entirely from random bytes; the version used everywhere unless you have a specific reason otherwise). **v1** (time-based, includes MAC address — discloses host info, rarely used now). **v3 and v5** (name-based via MD5 or SHA-1 hash — deterministic, same input produces same UUID). **v7** (newer, time-ordered random — better for database indexing than v4 because sorted by time, used in modern systems). For most use cases, v4 is the right default.
Is my generation sent to a server?
No — UUID generation runs entirely in your browser via `crypto.randomUUID()` (Web Crypto API). Zero HTTP requests, no server involvement. The random bytes come from the OS CSPRNG. Safe for any use case — generation is purely client-side cryptographic randomness.
Can two random UUIDs ever collide?
Theoretically yes; practically never. Random v4 UUIDs have 122 bits of randomness (the version and variant bits are fixed). That's 2^122 ≈ 5.3 × 10^36 possible values. To get a 50% probability of collision (birthday paradox), you'd need to generate ~2.7 × 10^18 UUIDs. If you generated a billion UUIDs per second, it would take 85 billion years to reach 50% collision probability. For any realistic application, UUID collisions are not a concern.
What's the difference between UUID and ULID / CUID / NanoID?
Newer alternatives to UUID. **ULID** (Universally Lexicographically Sortable Identifier): 26 characters, time-prefixed, sortable by creation time, base32 encoding (URL-safe). **CUID** (Collision-resistant ID): 25 chars, designed for horizontal scaling. **NanoID**: configurable length, URL-safe, smaller than UUID. All solve the same problem (distributed unique IDs) with different trade-offs. UUID v4 is the universal default; ULID is preferred when time-ordering matters (database indexing). UUID v7 (newer) provides similar time-ordering with the UUID standard.
Should I use UUID as a database primary key?
Yes for distributed systems (multiple writers, no central ID coordinator). Yes for distributed-friendly designs. **Caveats with UUID v4**: random distribution causes B-tree index bloat (rows scattered, poor cache locality). For performance-sensitive databases, use **UUID v7** (time-ordered, indexes better) or **ULID** (also time-ordered). For simple single-database apps, AUTO_INCREMENT integers are smaller and faster — UUID benefits only matter at scale. PostgreSQL has native `uuid` type; MySQL stores as BINARY(16) for efficiency.
Can I use UUIDs in URLs?
Yes — UUIDs are URL-safe (only hex digits and hyphens). A typical UUID URL: `/users/f47ac10b-58cc-4372-a567-0e02b2c3d479`. Trade-offs: long (36 characters), not human-friendly. For internal API URLs and resource IDs where uniqueness matters more than length, UUIDs work. For public-facing URLs where you want short identifiers, generate a UUID internally but expose a shorter ID (slug, base62-encoded sequence, ULID). Many systems pair UUID (internal) + slug (public-facing) for the best of both.
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