GUID Generator

The GUID / UUID Generator creates universally unique identifiers — the 128-bit values that look like f47ac10b-58cc-4372-a567-0e02b2c3d479 — ready to paste into code, a database, or a config file. GUID (Globally Unique Identifier) and UUID (Universally Unique Identifier) are two names for the same thing: Microsoft ecosystems tend to say GUID, everyone else says UUID.

It runs entirely in your browser — pick how many you want, choose the version and format, and click generate. Nothing is sent to a server, so the identifiers stay on your machine. It's built for the job a developer actually has: needing a primary key, a correlation ID, a test fixture, or a few hundred unique values right now, without writing a script.

A UUID is a 128-bit number, almost always written as 32 hexadecimal digits in five hyphen-separated groups (8-4-4-4-12). This tool produces two versions, and the difference matters:

• Version 4 (random) — the default, and the right choice for almost everything. Nearly all 128 bits are random, with a few fixed to mark it as version 4. The tool generates v4 using the browser's built-in crypto.randomUUID() where it exists (a cryptographically secure source), falling back to a Math.random()-based generator only on older browsers. With roughly 2¹²² possibilities, the chance of generating the same v4 twice is, for practical purposes, zero.
• Version 1 (timestamp) — derives part of the value from the current time plus a node/clock component, so values trend upward over time. This tool's v1 is a simplified, timestamp-based variant: it uses the current time with a random node and clock-sequence rather than your real network MAC address. It is not a byte-for-byte RFC 4122 v1 — treat it as a time-ordered-ish UUID for casual use, not a canonical v1 for a strict validator.

After generating, you can reshape the output two independent ways. Format changes how each UUID is written: Standard lowercase, UPPERCASE, No Dashes (hyphens stripped), {Braces} (the Microsoft style {f47ac10b-...}), or URN (urn:uuid:f47ac10b-...). Output changes how the whole batch is wrapped: one per line, a JSON array, or comma-separated SQL values. Everything is computed locally; Copy puts the block on your clipboard and Download saves it as a .txt file.

1. Set how many GUIDs you need in the count field (1 to 1000; defaults to 10).
2. Pick the version. Leave it on v4 (Random) unless you specifically want time-ordered values, then choose v1 (Timestamp).
3. Choose a format to match the destination: Standard for most code, UPPERCASE or {Braces} for .NET / Windows contexts, No Dashes for compact keys or URLs, URN when a spec wants a urn:uuid: prefix.
4. Choose an output wrapper: One per line for quick paste, JSON for fixtures or payloads, or SQL Values for an INSERT.
5. Click Generate. (A sample batch is also generated automatically when the page loads.)
6. Copy the result, or Download it as a .txt file.

Worked example — 3 lowercase v4 UUIDs as SQL values. Set count 3, Version v4 (Random), Format Standard, Output SQL Values, and click Generate. You get three freshly random identifiers, each in single quotes and comma-separated on their own lines, ready for a values list — for example '5b2c1f9a-3e44-4f0b-9a1c-7d6e2f8b0c11', then 'a1d9e7c2-6b03-4d8e-bf52-90c4e1a7d3f6'. Your values differ every time. The tool outputs just the quoted, comma-separated values; you supply the surrounding INSERT INTO ... VALUES (...). Switch Output to JSON for a ["...", "..."] array, or One per line for a plain list with no quotes or commas.

• Database primary keys — UUIDs for id columns that stay unique across tables, shards, or separate systems without a central counter. The SQL Values output drops straight into a seed script.
• Seeding & test fixtures — generate hundreds of unique IDs for a test database, load test, or mock API responses; pick JSON and paste, no throwaway script needed.
• Correlation / request IDs — a v4 UUID per request or trace makes logs across microservices joinable.
• .NET / Windows / config keys — the {Braces} and UPPERCASE formats match the Guid string style used across the Microsoft stack, registry entries, and project files.
• Idempotency keys, file names, tokens — the No Dashes format gives a compact 32-character string handy for URL-safe keys or unique file names.
• Anything needing a guaranteed-unique label — feature flags, message IDs, device identifiers, deduplication keys.

• Default to v4. Unless you have a concrete reason to want time-ordering, v4 (random) is the standard choice and what most libraries and databases expect.
• This tool's v1 is simplified. It's timestamp-based but uses a random node, so it won't satisfy a strict RFC 4122 v1 validator — and it doesn't leak a real MAC address (the reason many people avoid real v1). For a genuinely sortable time-based ID, the modern answer is UUIDv7, generated server-side, not v1.
• v4 isn't sortable. Random UUIDs scatter across an index, which can hurt insert performance on very large tables. For high-write tables consider a time-ordered scheme (UUIDv7 / ULID) as the clustered key instead of v4.
• Randomness depends on the browser. v4 is cryptographically secure when the browser provides crypto.randomUUID() (all current browsers do). A UUID is an identifier, not a secret — never use one as a password or API token.
• UUIDs are not unguessable by design. They prevent collisions, not enumeration — don't treat "has a valid UUID" as "is authorized".
• Format vs. output are independent. Format changes each value's text (case, braces, dashes, URN); Output changes how the batch is wrapped (lines / JSON / SQL). You can mix them, e.g. UPPERCASE + JSON.
• Case can matter to a comparator. UUIDs are case-insensitive by spec, but a naive string comparison isn't. Store and compare one consistent case (Standard lowercase is the common convention).
• Batch limit is 1000. Need more? Generate in batches, or do bulk generation server-side. See more developer tools for related utilities.

What's the difference between a GUID and a UUID? Nothing meaningful — they're the same 128-bit identifier. "GUID" is the term Microsoft popularized; "UUID" is the vendor-neutral name from the RFC. This tool produces values valid as either.

Which version should I pick — v1 or v4? Pick v4 for almost everything; it's random, standard, and reveals nothing about when or where it was made. Choose v1 only if you specifically want a timestamp-flavored value — and note this tool's v1 is a simplified, non-canonical variant. If your real goal is sortable time-based IDs, look at UUIDv7 rather than v1.

Are the generated UUIDs really unique? For v4, effectively yes. With about 2¹²² random bits, you'd have to generate an astronomically large number before a collision became even remotely likely, so they're safe to use as keys without a uniqueness check.

Can I use these as security tokens or passwords? No. A UUID is an identifier, not a secret. Even a cryptographically random v4 is meant to be unique, not confidential — use a purpose-built secret generator for anything security-sensitive.

Is my data sent anywhere? No. Generation happens entirely in your browser, so the UUIDs never leave your device. Copy or download them locally.