Expecting sequential ordering
UUID v4 values are intentionally random. They are poor substitutes for sortable IDs unless your database and index strategy account for randomness.
UUID v4 Generator Online | Bulk GUIDs with Web Crypto
ConverterRuns in Your Browser (No Uploads)
Generate RFC 4122-compliant random UUID v4 and GUID values securely using your browser's cryptographic API. Supports bulk generation, hyphen/case customization, copy/download output, and local-only privacy.
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What to do next
Continue with a related workflow or open the next tool that usually follows this task.
Workflow guide
Verify a file checksum with SHA-256
Use this workflow when a vendor, GitHub release, or teammate gives you a checksum and you need to confirm that the file you downloaded has not changed.
OpenRelated toolHash Generator Online | MD5, SHA-256 and SHA-512 Checksums
Generate MD5, SHA-1, SHA-256, and SHA-512 checksums locally.
OpenHow to Use This Tool
- 1
Select the number of UUIDs to generate (1–100).
- 2
Choose your preferred format: with or without hyphens, uppercase or lowercase.
- 3
Click 'Generate UUIDs' to produce secure UUIDs via the Web Crypto API.
- 4
Copy individual IDs, use Copy All, or download them as a .txt file.
When to Use This Tool
Database Keys and Seed Data
Generate unique primary keys, foreign keys, and seed values that can be created independently across services.
Request and Correlation IDs
Create request IDs and correlation IDs for tracing logs across APIs, queues, and background jobs.
File and Directory Naming
Assign unique names to files, uploads, exports, logs, and temporary directories across systems.
Distributed Systems
Create independent unique IDs across services and servers without central coordination or round trips to a database.
Documentation and Test Fixtures
Generate predictable sets of sample IDs for documentation, mocks, test fixtures, and API examples.
Common Mistakes
Changing UUID format blindly
Some APIs require the canonical hyphenated lowercase format. Match the downstream contract before removing hyphens or changing case.
Using IDs as access control
UUIDs are identifiers, not proof of permission. Do not use them alone as authorization secrets for protected resources or private links.
Examples
Generate database-safe IDs
Create lowercase UUID v4 values for database records, fixtures, or events that must be unique across services.
Input
Count: 3, lowercase, with hyphensOutput
9f8f12a4-7b9e-4e7d-a8c2-4f6c9ad12701
47d9d9d2-4a15-47bf-8f90-bd2a6f5e1c6a
c7aaf71d-b25d-4e2f-9a5e-7d250df3c8a9Generate compact IDs for fixtures
Remove hyphens when a compact identifier is easier to paste into tests, seed data, or log examples.
Input
Count: 2, lowercase, no hyphensOutput
9f8f12a47b9e4e7da8c24f6c9ad12701
47d9d9d24a1547bf8f90bd2a6f5e1c6aHow UUID v4 Generation Works
UUID v4 is a 128-bit identifier with 122 random bits. Version and variant bits are fixed according to RFC 4122.
This tool uses crypto.getRandomValues() to generate cryptographically strong random numbers directly in your browser.
The canonical format is xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. Hyphen and case options change presentation, not the underlying identifier value.
Frequently Asked Questions
Q.Can two UUIDs ever be the same?
A. UUID v4 uses 122 bits of randomness, giving about 5.3e36 possible values. The chance of collision is practically zero for normal application workloads.
Q.What's the difference between UUID v1 and v4?
A. UUID v1 includes timestamps and MAC addresses, potentially revealing system info. UUID v4 is purely random and privacy-safe.
Q.Is it safe? Does it send data to a server?
A. No. Everything runs locally using the Web Crypto API. Nothing is uploaded or stored.
Q.Can UUIDs be used as database primary keys?
A. Yes, UUIDs work well for distributed database keys because services can generate them without coordination. However, they are not sequential, so some databases may need index or storage tuning.
Q.Should I use UUID v4, ULID, or UUID v7?
A. Use UUID v4 when you need random uniqueness. Use ULID or UUID v7 when chronological sorting is important and your system supports those formats.
Related workflow guides
Use these focused guides when you need a practical workflow before opening the tool.
Workflow guide
Verify a file checksum with SHA-256
Use this workflow when a vendor, GitHub release, or teammate gives you a checksum and you need to confirm that the file you downloaded has not changed.
Workflow guideGenerate UUIDs for realistic test data
Use this workflow when you need realistic unique identifiers for examples, tests, seeded records, or temporary objects without exposing production IDs.
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