Question 1

What is the difference between UUID v4 and v7?

Accepted Answer

UUID v4 is fully random, offering maximum uniqueness but no ordering. UUID v7 embeds a Unix millisecond timestamp in the first 48 bits, making IDs sortable by creation time — ideal for database primary keys where insert order matters.

Question 2

Can I generate QR codes for URLs, Wi-Fi, or vCards?

Accepted Answer

The QR Code Generator accepts any text input. For URLs, paste the link directly. For Wi-Fi, use the standard WIFI:T:WPA;S:NetworkName;P:Password;; format. The tool generates the corresponding QR code instantly.

Question 3

How do I read a cron expression?

Accepted Answer

A cron expression has five fields: minute, hour, day-of-month, month, and day-of-week. For example, "0 9 * * 1-5" means "at 9:00 AM, Monday through Friday." The Cron Builder shows a human-readable description and the next scheduled runs.

Question 4

Are generated UUIDs truly unique?

Accepted Answer

UUID v4 uses 122 random bits from the Web Crypto API (crypto.getRandomValues), giving a collision probability of roughly 1 in 2^61 after generating a billion IDs. For all practical purposes, they are unique.

Question 5

Can I customize QR code colors and size?

Accepted Answer

Yes. You can set foreground and background colors, choose error correction level (L, M, Q, H), and adjust the module size. Higher error correction allows the QR code to remain scannable even if partially damaged.

Generators

About Generators

Frequently Asked Questions