UUID Generator
Generate random UUIDs (Universally Unique Identifiers) version 4. Create single or bulk UUIDs instantly.
Generator Settings
Preview Format
a1b2c3d4-e5f6-4890-a234-567890123456Generated UUIDs (0)
Why use our UUID Generator?
RFC 4122 Compliant
Generate version 4 UUIDs with cryptographically strong randomness suitable for production IDs.
Bulk Generation
Create one UUID or dozens at once for database seeds, test fixtures, and API mocks.
Generated Locally
IDs are created in your browser — no server round trip and no collision with remote state.
What is a UUID Generator?
A UUID (Universally Unique Identifier) is a 128-bit value formatted as 36 characters with hyphens, such as 550e8400-e29b-41d4-a716-446655440000. Version 4 UUIDs are random and designed so the probability of collision is negligible across distributed systems, making them ideal for primary keys, correlation IDs, and session tokens.
Our free online UUID generator creates RFC 4122 version 4 identifiers using secure browser randomness. Generate a single UUID for a new database row or batch hundreds for load tests and seed scripts. Copy individually or download the full list — all without signing up or installing anything.
UUID Generator Features
- Version 4 UUIDs:Random 128-bit identifiers with correct version and variant bits set per RFC 4122.
- Bulk output:Generate multiple UUIDs in one click for test data, migrations, or spreadsheet imports.
- Copy one or all:Copy a single UUID or the entire generated list to your clipboard instantly.
- Download list:Save generated UUIDs as a text file for scripts, SQL inserts, or CI fixtures.
- Secure randomness:Uses crypto.getRandomValues for unpredictable, collision-resistant output.
- Privacy:UUIDs are generated on your device — nothing is logged or stored remotely.
Common Use Cases
Database Primary Keys
Assign unique row identifiers in PostgreSQL, MongoDB, or SQLite without a central ID server.
API Correlation IDs
Attach a UUID to each request for distributed tracing across microservices and log aggregators.
Test Data Seeding
Populate staging databases and factory fixtures with realistic unique identifiers at scale.
File & Object Names
Generate collision-free filenames for uploads, S3 keys, and temporary storage paths.
Session & Event IDs
Create opaque session tokens or event-sourcing record IDs in event-driven architectures.
Client-Side Prototyping
Mock entity IDs in frontend prototypes before the backend ID service is wired up.
How to Use the UUID Generator
Choose Quantity
Set how many UUIDs you need — one for a single record or many for bulk seeding.
Generate UUIDs
Click generate to create version 4 UUIDs with secure random bytes.
Copy Results
Copy an individual UUID or the full list for pasting into SQL, JSON, or config files.
Download if Needed
Save the generated list as a text file for scripts, CI pipelines, or team handoffs.
Benefits of Using a UUID Generator
Globally Unique Without Coordination
Generate IDs on any client or server without a central sequence allocator.
Production-Grade Randomness
Version 4 UUIDs use 122 random bits — collision risk is astronomically low for practical systems.
Standard Format
Output matches what databases, ORMs, and cloud SDKs expect out of the box.
Fast Bulk Creation
Produce hundreds of IDs in seconds for load tests and migration dry runs.
No Dependencies
Skip installing uuid npm packages or Python modules for ad-hoc generation tasks.
Completely Free
Unlimited UUID generation with no API keys or rate limits.
UUID Generation Tips
- •v4 vs v1: Version 4 is random; version 1 is time-based. Most apps use v4 for opaque, unpredictable IDs.
- •Store as native UUID type: PostgreSQL and other databases have a UUID column type — avoid storing as plain VARCHAR when possible.
- •Lowercase is conventional: UUIDs are case-insensitive, but lowercase hex is the most common style in APIs and logs.
- •Index performance: Random UUIDs fragment B-tree indexes more than sequential IDs — consider ULID or UUIDv7 for high-insert tables.
- •Do not expose sequentially: Even random UUIDs in public URLs can be enumerated if access control is weak — always authorize requests.
- •Pair with hash generator: Hash a UUID with SHA-256 when you need a deterministic derivative key from a random seed.
Generate UUIDs Now
Whether you need a single database key, a batch of test fixtures, or correlation IDs for distributed tracing, our free UUID generator creates RFC 4122 version 4 identifiers instantly in your browser.
Scroll up, set the quantity, and generate locally with no registration required. Completely free, and your IDs are never sent to any server.
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Frequently Asked Questions
What version of UUID does this tool generate?
This tool generates version 4 (random) UUIDs compliant with RFC 4122. The version and variant bits are set correctly in each identifier.
How unique is a UUID?
Version 4 UUIDs contain 122 random bits. The chance of generating a duplicate is vanishingly small — roughly one in 5.3 × 10^36 for any given pair.
Can I generate multiple UUIDs at once?
Yes. Set the desired quantity and click generate to receive a list of unique version 4 UUIDs, ready to copy or download.
Are UUIDs generated on a server?
No. All UUIDs are created locally in your browser using cryptographically secure random values. Nothing is transmitted remotely.
What is the UUID format?
A standard UUID is 36 characters: 32 hexadecimal digits in five groups separated by hyphens (8-4-4-4-12), for example 550e8400-e29b-41d4-a716-446655440000.
Should I use UUIDs as database primary keys?
UUIDs work well for distributed systems and client-generated IDs. For very high-insert tables, consider time-sortable alternatives like UUIDv7 or ULID if index locality matters.
Is a UUID the same as a GUID?
Yes. GUID (Globally Unique Identifier) is Microsoft's term for the same 128-bit identifier standard defined in RFC 4122.
Is the UUID generator free?
Yes. It is completely free to use with no registration, downloads, or hidden fees.