How to Generate UUIDs in Python, JavaScript, PHP, Java and Go

A UUID (Universally Unique Identifier) is a 128-bit identifier that can be generated independently on any machine without a central coordinator. This post is a code reference — pick your language and copy the snippet. For a deeper look at UUID versions, database trade-offs, and when to use each type, see What Is a UUID and When Should You Use One?.

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Python

The uuid module is part of the Python standard library — no install needed.

import uuid

# UUID v4 (random) — most common
uid = uuid.uuid4()
print(uid)         # e.g. 550e8400-e29b-41d4-a716-446655440000
print(str(uid))    # string representation
print(uid.hex)     # without hyphens: 550e8400e29b41d4a716446655440000

# UUID v1 (time-based, includes MAC address)
uid_v1 = uuid.uuid1()
print(uid_v1)

# UUID v3 (name-based, MD5)
uid_v3 = uuid.uuid3(uuid.NAMESPACE_DNS, "devgizmo.co.uk")
print(uid_v3)

# UUID v5 (name-based, SHA-1) — preferred over v3
uid_v5 = uuid.uuid5(uuid.NAMESPACE_DNS, "devgizmo.co.uk")
print(uid_v5)

Bulk generation in Python

import uuid

uuids = [str(uuid.uuid4()) for _ in range(100)]
print("\n".join(uuids))

UUID v7 in Python (time-ordered)

UUID v7 is not yet in the standard library (as of Python 3.13). Use the uuid6 package:

pip install uuid6

import uuid6

uid = uuid6.uuid7()
print(uid)  # e.g. 018e7adf-5b12-7349-8a24-6c8b7f4b2a13

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JavaScript (Browser)

All modern browsers expose crypto.randomUUID() natively — no library needed.

// UUID v4, built-in (Chrome 92+, Firefox 95+, Safari 15.4+)
const uid = crypto.randomUUID();
console.log(uid); // "110e8400-e29b-41d4-a716-446655440000"

// Bulk generation
const uuids = Array.from({ length: 10 }, () => crypto.randomUUID());
console.log(uuids);

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Node.js

Built-in (Node.js 14.17+)

const { randomUUID } = require("crypto");

const uid = randomUUID();
console.log(uid);

TypeScript

import { randomUUID } from "crypto";

const uid: string = randomUUID();
console.log(uid);

UUID v7 in Node.js

npm install uuidv7

import { uuidv7 } from "uuidv7";

const uid = uuidv7();
console.log(uid); // "018e7adf-5b12-7349-8a24-6c8b7f4b2a13"

uuid npm package (all versions)

npm install uuid

import { v1, v3, v4, v5, NAMESPACE_DNS } from "uuid";

console.log(v4());                             // random
console.log(v1());                             // time-based
console.log(v5("devgizmo.co.uk", NAMESPACE_DNS)); // name-based

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PHP

PHP 7.0 and below — manual generation

<?php
function uuid4(): string {
    $data = random_bytes(16);
    $data[6] = chr(ord($data[6]) & 0x0f | 0x40); // version 4
    $data[8] = chr(ord($data[8]) & 0x3f | 0x80); // variant bits
    return vsprintf("%s%s-%s-%s-%s-%s%s%s", str_split(bin2hex($data), 4));
}

echo uuid4();

PHP 8.3+ — Uuid class (RFC 9562)

<?php
// Available from PHP 8.3 via the ramsey/uuid package or ext-uuid
// Most projects use Ramsey's library:
// composer require ramsey/uuid

use Ramsey\Uuid\Uuid;

$uid = Uuid::uuid4()->toString();
echo $uid;

// UUID v7
$uid7 = Uuid::uuid7()->toString();
echo $uid7;

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Java

Standard library (java.util.UUID)

import java.util.UUID;

public class UuidExample {
    public static void main(String[] args) {
        // UUID v4 (random)
        UUID uid = UUID.randomUUID();
        System.out.println(uid);
        System.out.println(uid.toString());

        // UUID from string
        UUID parsed = UUID.fromString("550e8400-e29b-41d4-a716-446655440000");
        System.out.println(parsed.version()); // 4

        // UUID v3 (name-based, MD5)
        UUID uid3 = UUID.nameUUIDFromBytes("devgizmo.co.uk".getBytes());
        System.out.println(uid3);
    }
}

Bulk generation in Java

import java.util.List;
import java.util.UUID;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

List<String> uuids = IntStream.range(0, 100)
    .mapToObj(i -> UUID.randomUUID().toString())
    .collect(Collectors.toList());

UUID v7 in Java

# Maven
<dependency>
    <groupId>com.github.f4b6a3</groupId>
    <artifactId>uuid-creator</artifactId>
    <version>5.3.7</version>
</dependency>

import com.github.f4b6a3.uuid.UuidCreator;

String uid7 = UuidCreator.getTimeOrderedEpoch().toString(); // UUID v7

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Go

Standard library (crypto/rand + manual RFC 4122 construction)

Go's standard library doesn't include a UUID package, but generating a v4 UUID manually is straightforward:

package main

import (
    "crypto/rand"
    "fmt"
)

func newUUIDv4() string {
    b := make([]byte, 16)
    _, err := rand.Read(b)
    if err != nil {
        panic(err)
    }
    b[6] = (b[6] & 0x0f) | 0x40 // version 4
    b[8] = (b[8] & 0x3f) | 0x80 // variant bits
    return fmt.Sprintf("%08x-%04x-%04x-%04x-%012x",
        b[0:4], b[4:6], b[6:8], b[8:10], b[10:])
}

func main() {
    fmt.Println(newUUIDv4())
}

Google UUID package (recommended)

go get github.com/google/uuid

package main

import (
    "fmt"
    "github.com/google/uuid"
)

func main() {
    // UUID v4
    uid := uuid.New()
    fmt.Println(uid.String())

    // UUID v7
    uid7, err := uuid.NewV7()
    if err != nil {
        panic(err)
    }
    fmt.Println(uid7.String())
}

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UUID Format Reference

xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx

Position	Meaning
M	Version digit (4 = random, 7 = time-ordered)
N	Variant bits (8, 9, a, or b for RFC 4122)

A UUID is always 36 characters including hyphens, or 32 hex characters without.

UUID Version Cheat Sheet

Version	Algorithm	Use case
v1	Time + MAC	Sortable; leaks MAC address
v3	MD5 name-based	Reproducible from known input
v4	Random	General purpose — most widely used
v5	SHA-1 name-based	Reproducible; preferred over v3
v7	Time + random	New default — sortable, DB-friendly

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