Bulk UUID Generation: 100+ UUIDs for Seeds, Imports, and Spreadsheets

Sometimes you need 50 UUIDs for a database seed file, 200 for a CSV import, or 1,000 to pre-populate a test environment. Clicking "generate" one at a time is not practical. This guide covers every efficient approach: terminal one-liners, script snippets, spreadsheet formulas, and how to add a UUID column to an existing CSV file.

Terminal One-Liners: Generate N UUIDs Instantly

Python (any platform):

# Generate 50 UUIDs, one per line
python3 -c "import uuid; [print(uuid.uuid4()) for _ in range(50)]"

# Save to a file
python3 -c "import uuid; [print(uuid.uuid4()) for _ in range(100)]" > uuids.txt

Node.js:

node -e "const {v4}=require('uuid'); for(let i=0;i<50;i++) console.log(v4())"

Linux/macOS with uuidgen:

# Generate 50 UUIDs
for i in $(seq 1 50); do uuidgen; done

# Save to file
for i in $(seq 1 100); do uuidgen; done > uuids.txt

PowerShell (Windows):

1..50 | ForEach-Object { [System.Guid]::NewGuid().ToString() }

# Save to file
1..100 | ForEach-Object { [System.Guid]::NewGuid().ToString() } | Out-File uuids.txt

Add a UUID Column to an Existing CSV File

If you have a CSV export and need to add a UUID primary key column to each row:

# Python approach — adds 'id' column as first column
import csv
import uuid

with open('input.csv', 'r') as fin, open('output.csv', 'w', newline='') as fout:
    reader = csv.DictReader(fin)
    fieldnames = ['id'] + reader.fieldnames
    writer = csv.DictWriter(fout, fieldnames=fieldnames)
    writer.writeheader()
    for row in reader:
        row['id'] = str(uuid.uuid4())
        writer.writerow(row)

Or with awk (Linux/macOS):

# Add UUID as first column (requires uuidgen)
# Note: generates one UUID per row using a subshell
awk 'NR==1 {print "id," $0; next} {cmd="uuidgen"; cmd | getline uuid; close(cmd); print uuid "," $0}' input.csv > output.csv

The Python approach is faster for large files since it doesn't spawn a subprocess per row.

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Generate JSON Seed Files with UUIDs

For database seed files in JSON format:

import uuid
import json
from datetime import datetime, timezone

def make_order(i):
    return {
        "id": str(uuid.uuid4()),
        "customer_email": f"user{i}@example.com",
        "total": round(10 + i * 5.50, 2),
        "created_at": datetime.now(timezone.utc).isoformat(),
    }

orders = [make_order(i) for i in range(1, 101)]

with open('seeds/orders.json', 'w') as f:
    json.dump(orders, f, indent=2)

print(f"Generated {len(orders)} orders")

This creates 100 order records, each with a unique UUID and realistic data. Adjust the factory function for any schema.

UUID in Google Sheets and Excel

Neither Google Sheets nor Excel has a native UUID function, but both support workarounds.

Google Sheets — formula approach:

=LOWER(DEC2HEX(RANDBETWEEN(0,4294967295),8)&"-"&DEC2HEX(RANDBETWEEN(0,65535),4)&"-4"&DEC2HEX(RANDBETWEEN(0,4095),3)&"-"&DEC2HEX(RANDBETWEEN(32768,49151),4)&"-"&DEC2HEX(RANDBETWEEN(0,281474976710655),12))

This generates a UUID v4-shaped string. Note: it uses RANDBETWEEN, which is not a CSPRNG — suitable for test data, not for security-sensitive IDs.

For bulk spreadsheet UUIDs, the fastest approach is to generate them outside the sheet and paste as values:

python3 -c "import uuid; [print(uuid.uuid4()) for _ in range(200)]" | pbcopy  # macOS — copies to clipboard

Then paste into the UUID column and use "Paste special → Values only" to prevent re-evaluation.

Database Seeds in Rails, Laravel, and Django

For framework seed files, generate UUIDs programmatically rather than hardcoding them:

Rails (db/seeds.rb):

100.times do |i|
  Order.create!(
    id: SecureRandom.uuid,
    customer_email: "user#{i}@example.com",
    total: (10 + i * 5.5).round(2)
  )
end

Laravel (database/seeders/OrderSeeder.php):

for ($i = 0; $i < 100; $i++) {
    Order::create([
        'id' => Str::uuid(),
        'customer_email' => "user{$i}@example.com",
        'total' => round(10 + $i * 5.5, 2),
    ]);
}

Django (management command):

for i in range(100):
    Order.objects.create(
        customer_email=f"user{i}@example.com",
        total=10 + i * 5.5,
        # id auto-generated by UUIDField default=uuid.uuid4
    )

In all three cases, the UUID is generated fresh per record — no pre-generated list needed. Use the free UUID generator above for one-off test values in Postman or manual database console inserts.

Frequently Asked Questions

What is the fastest way to generate 1,000 UUIDs?

Python one-liner: python3 -c "import uuid; [print(uuid.uuid4()) for _ in range(1000)]" — generates 1,000 UUIDs in under a second. Redirect to a file with > uuids.txt.

Can I generate UUIDs directly in SQL for bulk inserts?

Yes. PostgreSQL: gen_random_uuid() in a SELECT or INSERT. MySQL 8+: UUID() function. SQL Server: NEWID(). Use these in a loop or INSERT ... SELECT to generate bulk UUIDs without leaving the database.

Are Google Sheets RANDBETWEEN UUIDs safe to use in production?

No — RANDBETWEEN uses a non-cryptographic PRNG and recalculates on every sheet change. Use them for test data display only. For any real data, generate UUIDs in code.

How do I generate unique UUIDs across multiple CSV files?

UUID v4 collision probability is astronomically low — independently generated UUIDs across files will not collide. Just generate them independently per file; no coordination needed.