UUID Generator
Generate unique UUID identifiers in versions 1, 3, 4, 5 and 7. Everything runs in your browser — cryptographically secure.
Choose the UUID version that fits your needs: v4 for random IDs, v7 for time-sortable IDs, v1 for timestamp-based, or v3/v5 for deterministic name-based IDs.
How It Works
This UUID generator creates identifiers entirely in your browser — no data is sent to any server. Select a version, click "Generate", and get one or more unique UUIDs instantly.
UUID v1 — Timestamp
Based on the current timestamp and a random node ID. Sortable by creation time. Useful for distributed event logging where time ordering matters. Note: in this browser implementation, the node ID is random (not a real MAC address) for privacy.
UUID v3 — MD5 Name-Based
Generated by hashing a namespace UUID + name string with MD5. Deterministic: the same namespace + name always produces the same UUID. Useful for generating consistent IDs from known identifiers (domain names, URLs, etc.).
UUID v4 — Random (Most Popular)
Generated using 122 bits of cryptographically secure random data via crypto.getRandomValues(). The most widely used version — suitable for database primary keys, API identifiers, session tokens, and any scenario requiring unique IDs without coordination.
UUID v5 — SHA-1 Name-Based
Same concept as v3 but uses SHA-1 instead of MD5. Recommended over v3 for new applications as SHA-1 provides better distribution. Also deterministic: same input always produces the same UUID.
UUID v7 — Time-Ordered (Modern)
Defined in RFC 9562 (2024). Uses a Unix timestamp in milliseconds + random bits. Naturally sortable by creation time, making it ideal for database primary keys where index performance matters. Recommended as a modern replacement for v1.
Privacy First
All generation runs locally in your browser using JavaScript. No data is sent to any server — there are no requests, no cookies, and no tracking.
Frequently Asked Questions (FAQ)
Q: What is a UUID?
A: A UUID (Universally Unique Identifier) is a 128-bit identifier that is guaranteed to be unique. UUIDs come in several versions: v1 (time-based), v3 (MD5 hash), v4 (random), v5 (SHA-1 hash), and v7 (time-ordered random).
Q: What are the differences between UUID versions?
A: v1 uses timestamp + node ID. v3 uses MD5 hash of namespace + name. v4 uses purely random numbers. v5 uses SHA-1 hash of namespace + name. v7 uses Unix timestamp + random bits. v4 is the most popular, v7 is the modern choice for databases.
Q: Which UUID version should I use?
A: Use v4 for general-purpose unique IDs. Use v7 for database primary keys where time-ordering improves index performance. Use v3 or v5 when you need deterministic IDs from the same input. Use v1 for legacy compatibility.
Q: Is the generation done on the server?
A: No. All UUID generation happens directly in your browser using the Web Crypto API for cryptographically secure random numbers. Nothing is sent to the server.
Q: What is the difference between UUID and GUID?
A: UUID and GUID are the same thing. UUID is the standard term from RFC 4122/9562. GUID is Microsoft's term for the same concept.
Q: What are namespace UUIDs (v3 and v5)?
A: v3 and v5 are deterministic — the same namespace + name always produces the same UUID. Standard namespaces include DNS, URL, OID, and X.500. For example, the v5 UUID for "example.com" in the DNS namespace will always be the same.
Q: How many UUIDs can I generate at once?
A: You can generate from 1 to 100 UUIDs at once. Note: v3 and v5 are deterministic, so generating multiple with the same input produces identical UUIDs.
Q: Is this tool free?
A: Yes, completely free with no registration required. Use it as many times as you need.