Generate UUID in MongoDB

Mongoose schema with UUID _id

import mongoose from 'mongoose';
import { randomUUID } from 'crypto';

const orderSchema = new mongoose.Schema({
    _id: {
        type:    String,
        default: () => randomUUID(),  // UUID v4 string as _id
    },
    customer: { type: String, required: true },
    total:    { type: Number, required: true },
    status:   { type: String, enum: ['pending', 'paid', 'shipped'], default: 'pending' },
}, {
    _id: false,  // disable auto ObjectId generation
    timestamps: true,
});

const Order = mongoose.model('Order', orderSchema);

// Create an order - UUID auto-assigned
const order = await Order.create({ customer: 'Alice', total: 99.99 });
console.log(order._id); // → "f47ac10b-58cc-4372-a567-0e02b2c3d479"

MongoDB shell - UUID in mongosh

// In mongosh (MongoDB Shell)

// Generate a UUID
const id = UUID();
print(id.toString()); // → "f47ac10b-58cc-4372-a567-0e02b2c3d479"

// Insert with UUID _id
db.orders.insertOne({
    _id:      UUID(),
    customer: 'Alice',
    total:    99.99,
});

// Query by UUID
db.orders.findOne({
    _id: UUID('f47ac10b-58cc-4372-a567-0e02b2c3d479')
});

// Generate ObjectId (default)
const oid = new ObjectId();
print(oid.toString());         // → "663116800000000000000000"
print(oid.getTimestamp());     // → 2024-04-30T00:00:00.000Z

Python - PyMongo with UUID

import uuid
from pymongo import MongoClient
from bson.binary import Binary, UuidRepresentation
from bson.codec_options import CodecOptions

client = MongoClient("mongodb://localhost:27017")
db     = client["myapp"]

# Configure UUID representation (STANDARD = RFC 4122 BSON subtype 4)
opts = CodecOptions(uuid_representation=UuidRepresentation.STANDARD)
col  = db.get_collection("orders", codec_options=opts)

# Insert with UUID _id
order_id = uuid.uuid4()
col.insert_one({"_id": order_id, "customer": "Alice", "total": 99.99})

# Query by UUID
doc = col.find_one({"_id": order_id})
print(doc["_id"])  # → UUID('f47ac10b-58cc-4372-a567-0e02b2c3d479')

How do I generate a UUID in MongoDB?

MongoDB stores UUIDs as a native BSON binary type (subtype 4). In the mongo shell or Node.js driver you create one with UUID(), and most drivers map it to their language's native UUID type. You can use it as the _id field or keep MongoDB's default ObjectId - both index efficiently.

Is crypto.randomUUID() cryptographically secure?

Yes. crypto.randomUUID() uses the platform CSPRNG (operating system secure random source), suitable for session tokens, API keys, and idempotency keys. Do not use non-cryptographic random sources for security-sensitive identifiers.

What is the difference between UUID v4 and v7 in MongoDB?

UUID v4 (crypto.randomUUID() or equivalent) is fully random and not sortable. UUID v7 embeds a millisecond timestamp for chronological sorting (RFC 9562). Use v4 for general-purpose IDs; use v7 for database primary keys at scale.

Do I need to install a package for UUID generation in MongoDB?

A package or library install may be required. See the Installation section for the recommended approach in MongoDB.

How do I validate a UUID string in MongoDB?

Use the platform's UUID parse/validation function, or test against the RFC 4122 regex: /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i. Always validate external input at API boundaries.

Should I use UUIDs as database primary keys in MongoDB applications?

UUIDs work well as _id values in distributed MongoDB systems. Store them as the native BSON UUID (binary subtype 4) rather than as a hex string, so each value takes 16 bytes and indexes efficiently. For insert-heavy collections, consider UUID v7 so new _id values are time-ordered.

Can I generate UUIDs in MongoDB without a network connection?

Yes. UUID generation uses local OS entropy sources and does not require network access. Each call is independent and thread-safe on modern platforms.

What output formats are available in MongoDB?

The standard hyphenated lowercase string (36 chars) is the default. Most APIs also support 32-char hex (no hyphens) and 16-byte binary formats. Use string format for APIs and binary for database storage.

What RFC standards apply to MongoDB UUID generation?

Version 4 UUIDs follow RFC 4122. UUID v7 follows RFC 9562 (May 2024). Ensure your chosen method produces compliant version and variant bits.

When should I avoid UUID v1?

Avoid UUID v1 in security-sensitive contexts - it embeds MAC address and timestamp information. Prefer v4 (crypto.randomUUID() or equivalent) unless you need legacy Cassandra timeuuid compatibility.