How to Generate a UUID in JavaScript, Python, Go, Java, C# and SQL

Every mainstream language can produce a UUID with one line. Most have a built in for version 4, and support for version 7 is arriving fast. Here are the snippets you will actually use, grouped by language.

JavaScript in the browser

const id = crypto.randomUUID();
// "3b241101-e2bb-4255-8caf-4136c566a962"  (v4)

crypto.randomUUID() is available in every current browser. It only works on secure origins, meaning https or localhost. For v7 you need a library:

import { v4, v7 } from "uuid";
v4();  // random
v7();  // time ordered

Node.js

import { randomUUID } from "node:crypto";
const id = randomUUID();  // v4, built in since Node 14.17

The same uuid npm package used in the browser works in Node and adds v1, v3, v5, v6 and v7.

Python

import uuid

uuid.uuid4()   # UUID('9c5b94b1-35ad-49bb-b118-8e8fc24abf80')
str(uuid.uuid4())   # as a string
uuid.uuid5(uuid.NAMESPACE_URL, "https://mybittools.com")   # deterministic

Python 3.14 added uuid.uuid7() to the standard library. On older versions install the uuid7 or uuid-utils package.

Go

import "github.com/google/uuid"

id := uuid.New()          // v4
id7, err := uuid.NewV7()  // v7
s := id.String()

The standard library has no UUID package. The Google package above is the de facto standard.

Java and Kotlin

import java.util.UUID;

UUID id = UUID.randomUUID();   // v4
String s = id.toString();

The JDK only ships v4 and v3. For v7 use a library such as uuid-creator or java-uuid-generator.

C# and .NET

Guid id = Guid.NewGuid();          // v4
Guid id7 = Guid.CreateVersion7();  // v7, .NET 9 and later
string s = id.ToString();

.NET calls them GUIDs but they are ordinary UUIDs. See UUID vs GUID for the one byte order quirk to watch for.

Rust

use uuid::Uuid;

let id = Uuid::new_v4();
let id7 = Uuid::now_v7();

Enable the v4 and v7 features of the uuid crate in Cargo.toml.

PostgreSQL

SELECT gen_random_uuid();   -- v4, built in since PostgreSQL 13
SELECT uuidv7();            -- v7, PostgreSQL 18 and later

CREATE TABLE orders (
    id uuid PRIMARY KEY DEFAULT uuidv7(),
    total numeric
);

MySQL and MariaDB

SELECT UUID();                        -- v1 as a string
SELECT UUID_TO_BIN(UUID(), 1);        -- 16 byte binary, timestamp first
SELECT BIN_TO_UUID(id, 1) FROM t;     -- back to text

MySQL only generates v1. Generate v7 in your application and insert it as BINARY(16). MariaDB 10.7 added a native UUID column type.

SQLite

No built in generator. Create the UUID in your application. If you must do it in SQL, this produces a valid v4:

SELECT lower(hex(randomblob(4))) || '-' || lower(hex(randomblob(2))) || '-4' ||
       substr(lower(hex(randomblob(2))), 2) || '-' ||
       substr('89ab', abs(random()) % 4 + 1, 1) ||
       substr(lower(hex(randomblob(2))), 2) || '-' || lower(hex(randomblob(6)));

Command line

uuidgen                  # macOS and most Linux, v4
uuidgen -t               # v1 on Linux
cat /proc/sys/kernel/random/uuid   # Linux, v4
python3 -c "import uuid; print(uuid.uuid4())"

On Windows PowerShell, [guid]::NewGuid() does the same.

Without any code

When you just need a handful of IDs for a test fixture or a config file, our online UUID generator makes up to fifty v1, v4 or v7 UUIDs at a time with one click copy.

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