Generate random UUID v4 identifiers instantly — single or in bulk up to 1000, in standard, compact, braces, or URN format. 100% in your browser.
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UUID version 4 is the most widely used identifier format in software: a 128-bit value in which 122 bits are random. That randomness gives about 5.3 × 10^36 possible values, which is why v4 UUIDs can be generated anywhere — browsers, servers, mobile apps — without any coordination and with practically zero collision risk.
This generator creates RFC-compliant v4 UUIDs directly in your browser, one at a time or in bulk batches up to 1000, formatted as standard (hyphenated), compact (no hyphens), braces (Microsoft/GUID style), or URN. Copy individual values, copy all, or download the batch as a text file for database seeding and test fixtures.
Because a v4 UUID contains no timestamp and no machine identifier, it reveals nothing about when or where it was created — the right choice when identifiers must be unguessable and untraceable, such as session tokens, API keys' public ids, and externally visible resource ids.
Generating standard UUIDs is incredibly easy with our streamlined interface:
Generate up to 1000 UUIDs instantly using optimized client-side JavaScript calculations.
No data is sent over the network or saved to any external servers. Your UUIDs are generated directly on your machine.
Easily switch between time-based (v1), fully random (v4), and name-based hashed (v5) unique identifiers.
Format identifiers directly the way you need them—standard formats, compact strings, or enclosed in braces for specific coding environments.
Download massive lists of generated keys straight to a .txt file, perfect for database seeding.
Utilizes the standard RFC 4122 algorithms, ensuring an astronomically low, practically impossible chance of a collision.
Choosing the correct UUID version can significantly affect optimization and reproducibility. Here's a brief summary to help you pick correctly:
Generates identifiers utilizing the host machine's MAC address combined with a high-precision timestamp. This is excellent for ensuring guaranteed uncollision across localized networks and makes tracing back the generator machine possible.
Relies completely on pseudo-random numbers. Out of the 128 available bits, 122 are strictly random, providing vast cryptographic complexity. It requires no knowledge of the generating server, making it inherently safer and preventing node identification.
Needs two parameters: a namespace identifier and a raw string name. By applying a SHA-1 hash to these variables, you receive an identical, reproducible UUID anytime you provide the exact same namespace and string sequence inputs. Very popular in deterministic systems.
Standardized in RFC 9562, it embeds a 48-bit Unix millisecond timestamp followed by random bits. The result sorts naturally by creation time, making it the recommended choice for database primary keys — sequential index inserts with the distributed uniqueness of a UUID.
A version 4 UUID is a 128-bit identifier where 122 bits are randomly generated (6 bits are reserved to mark the version and variant). It looks like xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx — the third group always starts with 4.
In theory yes, in practice no. With 2^122 possibilities, you would need to generate a billion UUIDs per second for about 85 years to reach a 50% chance of a single collision. Treating them as unique is industry-standard practice.
You can, and many systems do — it lets clients generate keys without a round-trip and hides record counts. Note that random keys fragment B-tree indexes at very high insert rates; if that matters, consider time-ordered UUID v7 instead, which we also generate.
Look at the first character of the third group: 4 means version 4 (e.g. ...-4f3a-...). A 7 there means version 7, a 1 means version 1, and so on.
Generation happens entirely in your browser — nothing is sent to a server or logged. For cryptographic purposes (secrets, tokens with security value), always prefer a dedicated CSPRNG API in your own code.
Construct complex secure identifiers reliably for all of your developer requirements. Ready out of the box with standard formats and unlimited bulk execution.
No registration, no tracking of your content, no server uploads. Don't just take our word for it:
Your files and text are processed entirely on your device. Nothing is ever sent to us.
Once loaded, this tool keeps working with your Wi-Fi turned off. Try it.
Open your browser's DevTools → Network tab. You'll see zero requests carrying your data.
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