Skip to main content
Back to Numbers generators

Numbers

Bulk UUID Generator with Format Options

Used by developers, writers, and creators worldwide.

A bulk UUID generator with format options removes the friction of producing dozens of version 4 UUIDs by hand. Choose from four output formats — standard hyphenated, uppercase, no-hyphens, or brace-wrapped — and generate up to 100 UUIDs in a single pass. Developers reach for this when seeding databases, building fixture files, or populating migration scripts where one UUID at a time is too slow. Format choice matters in practice. PostgreSQL and most REST APIs expect standard lowercase. .NET and COM registries want brace-wrapped GUIDs. MySQL primary-key columns and Redis key schemes often use compact 32-character strings without hyphens. Everything runs in-browser via the Web Crypto API, so no identifiers are sent to a server.

Loading usage…

Free forever — no account required

How to use

  1. Choose your options above
  2. Click Generate
  3. Copy your result

Detailed instructions

  1. Set the count field to the number of UUIDs you need, between 1 and 100.
  2. Open the Format dropdown and select standard, uppercase, no-hyphens, or brace-wrapped to match your target system.
  3. Click Generate to produce the full list of UUIDs instantly in the output panel.
  4. Click Copy or select all output text and paste directly into your code, SQL script, or fixture file.

Use Cases

  • •Seeding 50 unique primary keys into a Postgres staging database before a load test
  • •Generating brace-wrapped GUIDs for a .NET COM component or Windows registry entry
  • •Populating JSON fixture files used by Vitest or Jest for frontend unit tests
  • •Pre-generating 100 no-hyphen UUIDs for a MySQL CHAR(32) bulk INSERT migration script
  • •Creating stable correlation IDs for distributed microservice request tracing in Postman

Tips

  • →For PostgreSQL native UUID columns, always use the standard lowercase format — it inserts without any casting.
  • →When seeding test data, generate one batch per table so each entity type gets its own isolated set of IDs.
  • →The no-hyphen format pairs well with Redis keys and short URL slugs where punctuation causes routing issues.
  • →Paste a batch into a spreadsheet column to quickly map generated UUIDs to test user names or record labels.
  • →If you need deterministic IDs across test runs, UUIDv4 won't help — use UUIDv5 with a fixed namespace instead.
  • →Brace-wrapped format is only needed for Windows COM/GUID registries; avoid it in web APIs where JSON parsers may reject the braces.

FAQ

what's the difference between a uuid and a guid

GUID is Microsoft's name for the same 128-bit UUID standard. The only practical difference is presentation: GUIDs are typically brace-wrapped like `{550e8400-e29b-41d4-a716-446655440000}`. Select the braces format here when working with .NET, COM, or Windows registry entries.

is it safe to use uuid v4 as a secret token or api key

No. UUIDv4 is built for uniqueness, not secrecy — its structure is public and it carries less than full 128-bit entropy once the version and variant bits are fixed. For session tokens or API keys, use a dedicated cryptographically secure random token generator that outputs 256-bit entropy without a fixed format.

why store a uuid without hyphens in mysql or redis

Dropping the four hyphens shrinks the value from 36 to 32 characters, which reduces index size noticeably in high-volume tables using UUID primary keys. MySQL's CHAR(32) column is also faster to index than VARCHAR(36), and Redis key schemes avoid any hyphen-escaping edge cases.