system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do some online payment processors require the CVV code and others don't?
gpt
Two main reasons.

You can process a payment without a CVV but there's a higher degree of fraud. Bigger companies may accept that risk because it's still a small percentage of their overall payments. Smaller companies like mom and pop stores will suffer badly with a fraud payment so they absolutely need the CVV.

Also some nasty websites will store the CVV after the first time you use it, and provide it automatically. However this is a MASSIVE risk and they may get shut down or fined over it. There's an entire audit process called PCI around this.