UUID / GUID generator

Client

Create cryptographically strong random UUID v4 values for IDs, test data, and placeholders. Choose how many to emit, optional uppercase GUID style, and a separator—everything runs in your browser.

Options

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Version 4 identifiers use random bits (RFC 9562). They are suitable for request IDs, keys, and placeholders—use a dedicated system if you need guaranteed uniqueness across distributed databases.

Separator

Common use cases

  • Generate RFC 9562 random UUID v4 values for database primary keys and API ids.
  • Create many unique ids at once for fixtures, load tests, or mock services.
  • Copy a batch as newline- or comma-separated text for spreadsheets or tickets.

Common mistakes to avoid

  • Assuming UUIDs are always secret

    UUID v4 values are random, but anyone who sees one can reference the same record. Do not use them as authentication tokens by themselves.

  • Relying on uppercase in all systems

    The canonical string is lowercase hex with hyphens. Some systems normalize case; others compare literally—pick one style per integration.

  • Confusing version numbers

    This tool generates version 4 (random). Other versions (for example time-based) use different algorithms and are not produced here.

FAQ

Are these UUIDs cryptographically strong?

They are generated with your browser’s cryptographically strong random source when available, suitable for typical application identifiers.

Does generation run on your servers?

No. Values are created locally in your tab and never sent to Toolcore.

Can I get UUIDs without hyphens?

Use copy options in the workspace if provided, or remove hyphens in your editor—the underlying value is the same 128-bit id.

More tools

Related utilities you can open in another tab—mostly client-side.