How to Generate UUID v7 in JavaScript, Python, .NET, Go and SQL

Quick Reference

JavaScript and TypeScript

npm install uuid

import { v7 as uuidv7 } from 'uuid';

const id = uuidv7();  // e.g. '0192f0c1-6a4b-7c3d-9e2f-0a1b2c3d4e5f'

Browsers' and Node's built-in crypto.randomUUID() produces version 4 only. How to generate a UUID in JavaScript covers v4 and the rest of the uuid package.

Python

import uuid

u = uuid.uuid7()   # Python 3.14+
print(str(u), u.version)

On Python 3.13 and earlier, uuid doesn't include uuid7(); use a third-party package or upgrade. How to generate a UUID in Python covers conversions and framework defaults.

C# and .NET

Guid id = Guid.CreateVersion7();                         // current UTC time
Guid at = Guid.CreateVersion7(DateTimeOffset.UtcNow);    // explicit timestamp

Available from .NET 9. When storing these in SQL Server uniqueidentifier columns, remember SQL Server's unusual sort order, covered in GUID as a primary key.

Go

import "github.com/google/uuid"

id, err := uuid.NewV7()
if err != nil {
    // handle error
}
fmt.Println(id.String())

PostgreSQL

SELECT uuidv7();

CREATE TABLE events (
  id uuid PRIMARY KEY DEFAULT uuidv7(),
  payload jsonb
);

Available from PostgreSQL 18. UUID v7 in PostgreSQL covers extracting timestamps and older versions.

Java

Java's java.util.UUID can parse and store any version, but its built-in generators are randomUUID() (v4) and nameUUIDFromBytes() (v3). For v7, use a maintained third-party library and check it against RFC 9562. Store the result as a UUID object, and in databases as a native UUID type.

What to Check in a v7 Library

RFC 9562 leaves some choices to implementations, so libraries differ. Check:

• RFC 9562 compliance: correct version (7) and variant bits.
• Random source: a cryptographically secure generator for the random bits.
• Monotonicity: whether values from one generator increase within the same millisecond (via a counter or sub-millisecond precision), if your use needs that.
• Clock handling: what happens if the system clock moves backwards.
• Maintenance: recent releases and tests.

Verifying Your Output

Whatever you generate, a quick sanity check catches mistakes:

1. The 13th hex digit should be 7.
2. The 17th should be 8, 9, a or b.
3. The first 12 hex digits, read as a millisecond timestamp, should be close to "now".

The UUID decoder shows all three: version, variant and the embedded timestamp. The UUID validator checks hundreds of values at once.

Without Writing Code

For fixtures, documentation or manual testing, the UUID v7 generator creates up to 1,000 values in your browser and can wrap them in quotes or output them as a JSON array, ready to paste into code. It uses the Web Crypto API for the random bits.

Testing Code That Uses UUID v7

Time-based IDs make tests harder to write deterministically. Approaches:

• Inject the generator: pass a function or interface that creates IDs, and use a fixed implementation in tests.
• Freeze time where your library reads the clock, if it supports a time provider (for example Guid.CreateVersion7(timestamp) in .NET).
• Assert on shape, not value: check the version digit and that values from one generator increase, rather than comparing exact strings.

Migrating an Existing System

1. Switch the generator for new records to v7.
2. Update any validation that only accepts v4.
3. Leave existing IDs unchanged; they remain valid UUIDs.
4. If you sort by ID anywhere, remember that old v4 rows won't be in time order.

UUID v4 vs UUID v7 covers the trade-offs behind the switch.

Summary

Use built-ins where available (.NET 9, Python 3.14, PostgreSQL 18) and trusted libraries elsewhere. Check the version digit, variant and timestamp to confirm your setup produces real v7 UUIDs.