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Generate RFC 4122 UUID version 4 GUIDs instantly — 1 to 100 per batch, four output formats, unique results by default, and one-click newline copy. Uses crypto.randomUUID when available with a validated v4 fallback.
Also try the UUID Generator, API Key Generator, and more in Utility tools.
Last updated: May 19, 2026 · Published: 2026-03-27 · Updated: 2026-05-19
Generates RFC 4122 style v4 GUIDs for testing and development workflows.
Set options and click generate
A GUID generator (also called a UUID generator) creates version 4 identifiers — random 128-bit values formatted as hex strings. Developers use them for database keys, API resource ids, session tokens in test environments, and fixture data without coordinating a central id server.
Muxgen runs generation in your browser: set count and format, click generate, copy a list. No account and no server-side storage of your identifiers.
Three steps to copy-ready UUID v4 output.
Choose how many GUIDs to create in one batch — default is 1.
Standard, Uppercase, With braces, or No hyphens; leave duplicates off for unique batches.
Click Generate GUID(s), review the list, Copy to clipboard as newline-separated text.
Every control in the live GUID component panel.
Number input clamped to max 100 — invalid or empty input resets to 1.
Standard (default), Uppercase, With braces, No hyphens — applies to every ID in the batch.
Checkbox — when off, a Set dedupes formatted strings within the same generation run.
Primary action — rebuilds the results panel and clears copied state.
Monospace cards per ID, scrollable when many values; empty state until first generate.
Joins results with newlines; uses Clipboard API with textarea fallback; 2s Copied! feedback.
Four format pills and when to use each.
Default crypto.randomUUID shape, e.g. 550e8400-e29b-41d4-a716-446655440000 — 36 characters.
Same segments with A–F hex — common in Windows and some enterprise logs.
Wraps standard form in { } — used in some COM and legacy .NET examples.
32 contiguous hex characters — compact for URLs or char(32) columns.
What RFC 4122 means for generated strings.
The third group starts with 4 (13th hex digit) — indicates random UUID version 4.
First character of the fourth group is 8, 9, a, or b per RFC 4122 variant rules.
8-4-4-4-12 hex groups — 32 hex digits plus four hyphens in canonical form.
Tool rejects candidates that fail v4 pattern check before showing in results.
Preferred source in modern browsers — cryptographically strong random UUID.
Manual v4 assembly when randomUUID is unavailable — still validated before output.
Where newline-copied GUID lists land in real projects.
Paste newline list into INSERT statements for uuid or char columns.
Feed formatted IDs into path params and JSON body id fields.
Populate lists and maps in React/Vue state without hard-coded IDs.
Generate up to 100 unique IDs per click for staging volume tests.
Pair GUID batches with JSON Formatter when debugging REST payloads, or API Key Generator when you need auth secrets rather than record ids.
Hardware-style identifiers use different rules — see IMEI Generator for checksum-based device numbers.
Aligned with the live GUID generator component.
Version and variant bits set correctly on every accepted GUID.
Standard, uppercase, braced, and hyphen-free without manual editing.
One-click bulk generation for fixtures and QA matrices.
Optional Allow duplicate GUIDs when you intentionally need repeats.
Invalid candidates are skipped so listed IDs match v4 shape.
No sign-up; IDs generated locally in the browser.
When bulk UUID v4 generation saves time.
Primary keys for Postgres uuid, SQL Server uniqueidentifier, or char(36) columns.
Exercise parsers, validators, and OpenAPI uuid format constraints.
Temporary entity ids for kanban cards, comments, and drag-and-drop lists.
Consistent format (especially No hyphens) for import pipelines.
Newline copy into Cypress, Playwright, or Postman data files.
Synthetic correlation and session ids in demo environments.
Naming, formats, and related Muxgen utilities.
Same 128-bit standard — Microsoft ecosystems often say GUID; open-source docs often say UUID.
Both on Muxgen for v4 — pick the page title your team searches for.
This tool is v4 only (random). Time-based v1 or name-based v3/v5 need different generators.
Use Standard for most DB uuid types; No hyphens when storage or URLs omit separators.
Default unique per run; enable duplicates only for edge-case stress tests.
GUIDs identify records; API Key Generator builds authentication secrets with different charset rules.
Terms developers search alongside v4 generators.
Universally Unique Identifier — 128-bit value, usually shown as hex with hyphens.
Globally Unique Identifier — Microsoft term for the same identifier family as UUID.
IETF spec defining UUID layout, versions, and variant field semantics.
Random UUID — most common choice for database primary keys today.
Bits in the fourth group that mark UUID vs legacy formats — 10xx in binary.
Lowercase hex with hyphens in 8-4-4-4-12 grouping — 36 characters total.
Safer dev and QA usage after you copy IDs.
Confirm native uuid vs char(36) vs binary(16) before picking Standard vs No hyphens.
Document which seed file used which batch so you can truncate test data safely.
Leave Allow duplicate GUIDs off unless testing collision handling.
Run one generated ID through ORM and API validators before bulk imports.
Many systems normalize to lowercase — avoid unnecessary case mismatches.
Generate fresh v4 values for prod; reserve this tool for dev and QA fixtures.
Habits that pair with format pills and bulk copy.
Paste directly into .env lists, CSV columns, or array literals in scripts.
With braces format matches some C# Guid.Parse examples without manual wrapping.
Inspect API responses where id fields should match your chosen format.
Scheduled jobs from Cron Expression Generator can log new GUIDs per run.
Click generate again for more — keeps the UI responsive in the browser.
Check both Muxgen UUID tools if you need feature parity across team bookmarks.
UUID v4, batch limits, four formats, duplicates, validation, copy, and privacy.
Explore more tools in the directory.
Alternate Muxgen page for v4 UUIDs — compare formats and batch controls.
Mock API keys with charset and length controls for auth testing.
Strong secrets for service accounts paired with new entity IDs.
Pretty-print API payloads that include uuid fields after generation.
Schedule jobs that create or process records keyed by GUIDs.
Device identifiers with checksum rules for hardware-style test data.