UUID Generator

The UUID Generator produces RFC 4122 version 4 UUIDs in bulk using the Web Crypto API, so every identifier comes from a cryptographically secure random source rather than a predictable PRNG. The count control accepts a number between 1 and 500 through a numeric field or a slider, and the tool generates that many unique IDs in one click — each a fresh 128-bit value rendered in the standard 8-4-4-4-12 hexadecimal layout. Three formatting switches compose freely: Uppercase converts the hex digits, Hyphens removes the dashes for compact 32-character forms, and Braces wraps the result in curly brackets for C-style contexts. The tool generates automatically on first load and refreshes with the Generate button, while Copy all places the entire batch on your clipboard as a newline-separated list ready for a seed script or fixture file. A status row confirms the count, the v4 version, and the Web Crypto source of randomness, and the output can be downloaded as uuids.txt. Whether you are minting database primary keys, correlation IDs for logs, or test data for an API suite, generating a batch of UUIDs for seeding has never been faster.

1. 1

   Set the number of UUIDs with the number field or the slider (1–500).

2. 2

   Toggle Uppercase, Hyphens, or Braces to shape the output format.

3. 3

   Click Generate to draw a fresh batch from the Web Crypto API.

4. 4

   Press Copy all to put the entire list on the clipboard at once.

5. 5

   Download the batch as uuids.txt from the result box when you need a fixture file.

• Generating primary keys for database seed data during development.
• Creating correlation IDs to trace a request across microservice logs.
• Producing unique test fixture identifiers in an end-to-end test suite.
• Assigning anonymous client IDs for analytics without using email addresses.
• Keying distributed jobs or messages so retries never collide.
• Filling in placeholder IDs in API documentation examples.

• Use v4 UUIDs for identifiers that must never collide, not for anything security-sensitive — they are random, not secret.
• Store UUIDs as native UUID types in databases, or as 36-character strings; the hyphen-free form only matters for fixed-width fields.
• Do not re-seed or hand-edit generated UUIDs; modifying bits can break the version and variant markers.
• Generate in bulk only what you need — each batch draws fresh entropy, so batches never repeat.
• The braces form is mainly for C-style code and GUID text; remove them when pasting into JSON or SQL.
• When you need sortable or time-ordered IDs, pick ULIDs or v7 UUIDs instead — v4 values are fully random.

• Leave Hyphens on for databases and JSON; the canonical form is what most libraries expect.
• Press Copy all instead of selecting text — the clipboard gets the entire batch in one action.
• Keep the Braces switch off unless a C-style macro or Windows registry needs the GUID look.
• For fixture files, generate once, download uuids.txt, and commit it — tests run faster and stay deterministic.