UUID / GUID Batch Generator
Generate up to 10,000 cryptographically secure UUID v4 (random) or UUID v7 (time-ordered) identifiers in a single click. All generation happens locally in your browser using the Web Crypto API.
Generate up to 10,000 cryptographically secure UUID v4 or UUID v7 identifiers in one click, entirely in your browser using the Web Crypto API.
UUID v4 (Random): All 122 non-fixed bits are filled with cryptographically random values via crypto.getRandomValues(). Best for primary keys, session tokens, and IDs that must be globally unique and opaque.
Instant Batch Generation up to 10,000 UUIDs
Generate between 1 and 10,000 UUID identifiers in a single click. The entire batch is produced in milliseconds entirely in your browser with no server round-trip or latency penalty regardless of batch size.
Cryptographically Secure Randomness
UUID v4 generation uses crypto.getRandomValues() from the Web Crypto API — the same CSPRNG used by password managers and key generators. Generated IDs are statistically unique across all devices and time.
UUID v4 & v7 with 5 Output Formats
Choose between random UUID v4 and time-ordered UUID v7 identifiers. Export results in standard hyphenated, uppercase, no-hyphen, brace-wrapped, or URN formats for maximum compatibility with any language or framework.
100% Free — No Signup, No Limits
Generate as many batches as you need at absolutely no cost. No registration, no API keys, no rate limiting. Open the page and start generating UUIDs in seconds, whether you are online or working offline.
Database Primary Keys
Generate UUID v4 identifiers to pre-populate a batch of primary keys before inserting new rows into PostgreSQL, MySQL, or MongoDB. Using UUIDs instead of auto-increment integers prevents key enumeration and simplifies distributed database merges without row-number conflicts.
Distributed Event IDs
Use UUID v7 identifiers in event-driven architectures and message queues. Because v7 embeds the millisecond timestamp in the leading bits, events sort naturally by insertion time in B-tree indexes, dramatically improving range-query performance on time-series tables.
API Testing & Mocking
Pre-generate a batch of unique UUIDs to seed Postman collections, mock API fixtures, or OpenAPI example schemas. Having a list of realistic-looking IDs ready lets you write integration tests that simulate real-world multi-user scenarios without writing extra setup code.
Session & Token Seeds
Generate UUID v4 values as the base for session tokens, CSRF nonces, or one-time link identifiers. Because every UUID v4 has 122 bits of entropy from a CSPRNG, brute-force guessing or enumeration is computationally infeasible with standard hardware.
File & Object Naming
Name uploaded files or S3 / Cloudflare R2 objects with UUID v4 keys to avoid collisions across users and deployments. Content-addressable storage based on UUIDs eliminates overwrite risks and simplifies cache invalidation without knowing the original filename.
Kubernetes & Container IDs
Pre-assign UUID identifiers to Kubernetes resource manifests, Docker container labels, or Helm release names during CI/CD pipeline generation. Deterministic unique labels prevent race conditions in parallel deployment pipelines where multiple jobs provision resources simultaneously.
The Aback Tools UUID / GUID Batch Generator creates batches of cryptographically secure unique identifiers entirely inside your browser. No server communication, no account required, and no rate limits. Choose between UUID v4 (random) and UUID v7 (time-ordered), select an output format, set the batch size, and download or copy your identifiers instantly.
UUID v4 — Pure Randomness
UUID v4 identifiers (RFC 4122) are populated with 122 bits of cryptographically secure random data generated by crypto.getRandomValues() — the same CSPRNG used by browser-native password managers and TLS implementations. The remaining bits encode the version (4) and variant (RFC 4122) according to the specification. UUID v4 is the safest choice for primary keys, session tokens, and API identifiers where global uniqueness and opacity are paramount.
UUID v7 — Time-Ordered Identifiers
UUID v7 (RFC 9562) embeds the 48-bit Unix timestamp in milliseconds into the most significant bits of the identifier, followed by 74 bits of random data. This design produces identifiers that sort naturally by creation time in B-tree database indexes, which dramatically reduces page splits and fragmentation compared to random UUID v4 keys. UUID v7 is the recommended choice for time-series tables, event stores, message queues, and any workload where insertion order matters.
Output Formats
Five output formats are supported. The standard format produces the canonical hyphenated lowercase representation used by most frameworks and databases (e.g., 550e8400-e29b-41d4-a716-446655440000). Uppercase produces the same layout in capital letters for SQL environments that require it. No hyphens removes separators for compact storage or URL-safe embedding. Braces wrap the identifier in curly braces for use with Microsoft SQL Server, .NET, or Windows Registry formats. URN prepends the urn:uuid: namespace for use in XML and web resource contexts.
Collision Probability
UUID v4 has 122 bits of entropy. Generating 1 billion UUIDs per second for 86 years would yield only a 50% probability of a single collision — making practical collisions functionally impossible. UUID v7 shares the same collision guarantees for the random portion; two identifiers generated in the same millisecond on different machines are extremely unlikely to collide due to the 74 random bits appended after the timestamp.
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Frequently Asked Questions About UUID / GUID Generation
UUID v4 uses 122 bits of pure cryptographic randomness with no embedded metadata, making it fully opaque and globally unique. UUID v7 encodes the current Unix timestamp in milliseconds in the first 48 bits, so identifiers sort naturally by creation time — which significantly improves database index performance for time-series workloads.
UUID v4 has 122 bits of entropy from a CSPRNG, giving a collision probability so low it is practically impossible. You would need to generate a billion UUIDs per second for 86 years before a 50% chance of a single collision. UUID v7 shares the same guarantees for its 74 random bits appended after the timestamp.
It means the random bits in each UUID are generated using crypto.getRandomValues() — the Web Crypto API's CSPRNG — rather than Math.random(). A CSPRNG produces output that is computationally indistinguishable from true randomness, so generated IDs cannot be predicted or reproduced by an attacker who observes previous outputs.
Use UUID v7 for new relational database tables (PostgreSQL, MySQL). The time-ordered prefix prevents B-tree index fragmentation caused by random insertions, leading to faster writes and queries. For read-heavy or distributed NoSQL stores where insertion order does not matter, UUID v4 is fine.
The tool supports batches of 1 to 10,000 UUIDs per generation. All identifiers are created synchronously in your browser's JavaScript engine, which can produce 10,000 UUIDs in well under 100 milliseconds on modern hardware.
Five formats are supported: standard hyphenated lowercase (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx), uppercase, no-hyphens for compact storage, brace-wrapped for .NET and SQL Server compatibility, and URN (urn:uuid:...) for XML and web namespaces. The entire batch switches format instantly with no regeneration needed.
Yes. GUID (Globally Unique Identifier) is Microsoft's term for the same UUID specification defined in RFC 4122. The underlying format, generation algorithm, and collision guarantees are identical. The terms are interchangeable, although Microsoft systems often use the brace-wrapped format ({xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}).