Generate universally unique identifiers and modern alternatives — UUID v4/v7/v1, ULID, NanoID and CUID2. Randomness comes from your browser's cryptographic generator (crypto.getRandomValues). Click any value to copy it.
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Deterministic: the same namespace + name always produces the same {{version}} UUID — nothing here uses crypto.getRandomValues.
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This version does not embed a recoverable timestamp{{[3,5].includes(decoded.version) ? ' — v3/v5 are one-way hashes of namespace + name, not reversible' : ''}}.
UUID v4 — 122 random bits. The safe default when you just need a collision-resistant identifier and don't care about ordering.
UUID v7 — a 48-bit Unix millisecond timestamp followed by random bits. Time-sortable, which keeps database indexes tidy while staying unique.
UUID v1 — timestamp plus a node id. Here the node and clock sequence are randomized (no real MAC address is exposed).
UUID v3 / v5 — deterministic, not random: an MD5 (v3) or SHA-1 (v5) hash of a namespace UUID plus a name. The same namespace + name always produces the same UUID, which is the point — use it to derive a stable id for something you can name consistently (a URL, a file path) without a database round-trip. v5 is the one to prefer for new use; v3 exists mainly for interop with older systems that still expect MD5. Neither is reversible — the name cannot be recovered from the UUID.
ULID — 26-character Crockford Base32, lexicographically sortable and case-insensitive. Compact and URL-friendly.
NanoID — 21-character URL-safe id (A–Z, a–z, 0–9, _-). Shorter than a UUID with comparable collision resistance.
CUID2 — a lowercase, hash-derived id designed to be hard to guess and safe in URLs. This is a compatible implementation using SHA-256.
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