UUID Generator Online Free — Generate UUID v1, v4, v5, ULID & NanoID
Free online UUID generator supporting all major identifier formats: UUID v4 (random), UUID v1 (time-based), UUID v5 (name-based, deterministic), ULID (lexicographically sortable), and NanoID (URL-friendly). Bulk generate up to 1000 IDs, export in multiple formats, validate existing UUIDs, and inspect UUID structure. All generation uses cryptographically secure browser APIs — nothing is uploaded.
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How to Generate UUIDs Online Free
- 01
Select version
Choose UUID v4 (random), v1 (time-based), v5 (name-based), ULID, or NanoID. Each has different uniqueness and sorting properties.
- 02
Generate
Click Generate or press Space/Enter to create a new ID instantly. Configure v5 namespace, NanoID size, or bulk count as needed.
- 03
Copy or export
Copy the single UUID, generate up to 1000 in bulk, and export as plain text, JS array, JSON, or SQL INSERT VALUES.
Features
- ✓UUID v4: cryptographically random via crypto.randomUUID()
- ✓UUID v1: time-based with timestamp encoding
- ✓UUID v5: name-based, deterministic (SHA-1)
- ✓ULID: lexicographically sortable, Base32 encoded
- ✓NanoID: configurable size and alphabet
- ✓Bulk generation: 1–1000 IDs in one click
- ✓Export: plain text, JS array, JSON, SQL INSERT
- ✓Validate and inspect any UUID (version, timestamp)
UUID Version Comparison
| Version | Algorithm | Sortable | Reproducible | Best for |
|---|---|---|---|---|
| UUID v4 | Random | — | — | General purpose, DB primary keys |
| UUID v1 | Time + MAC | Roughly | — | Ordered inserts, event IDs |
| UUID v5 | SHA-1 hash | — | ✓ | Deterministic IDs from known inputs |
| ULID | Time + random | ✓ | — | DB indexes, ordered records |
| NanoID | Random | — | — | Short URLs, tokens, user-facing IDs |
Frequently Asked Questions
- What is a UUID and what is it used for?
- A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify information in computer systems. UUIDs are used as primary keys in databases, session tokens, transaction IDs, file names, and anywhere a unique identifier is needed without central coordination. The standard format is 32 hexadecimal characters displayed in 5 groups: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
- What is the difference between UUID v1, v4, and v5?
- UUID v1 is time-based — it encodes the current timestamp and MAC address, making it monotonically increasing and traceable to a time and machine. UUID v4 is randomly generated using cryptographically secure random bytes — it has no predictable structure and is the most commonly used version. UUID v5 is name-based using SHA-1 hashing — the same namespace and name always produce the same UUID, making it deterministic and reproducible.
- What is a ULID and how does it differ from a UUID?
- A ULID (Universally Unique Lexicographically Sortable Identifier) encodes a 48-bit timestamp in the first 10 characters followed by 80 bits of randomness. Unlike UUIDs, ULIDs sort lexicographically in the order they were created, making them better for database indexing. They use a case-insensitive Crockford Base32 encoding (26 characters) instead of hex.
- What is NanoID and when should I use it?
- NanoID is a URL-friendly unique ID generator that produces shorter IDs than UUIDs using a configurable alphabet. The default 21-character NanoID using 64 characters has a similar collision probability to UUID v4. Use NanoID when you need shorter IDs for URLs, tokens, or user-facing identifiers where compactness matters.
- How do I use UUID v5 (name-based)?
- UUID v5 takes a namespace UUID and a name string, applies SHA-1 hashing, and always produces the same UUID for the same input pair. Common namespaces are DNS (for domain names), URL (for URLs), OID (for object identifiers), and X500 (for distinguished names). For example, the DNS namespace with "example.com" always produces the same v5 UUID.
- Is it safe to generate UUIDs in the browser?
- Yes. This tool uses the browser's built-in crypto.randomUUID() for UUID v4 and crypto.getRandomValues() for NanoID, which are cryptographically secure APIs available in all modern browsers. UUID v1 uses a time-based approximation. All generation happens locally — nothing is sent to a server.