[gitgud]

Like others have mentioned, there’s many ways:

- Hash each pdf, check if it’s been run for free before

- Hash IP addresses, check before allowing free trial (can lead to many false positives though)

- Use local storage or cookies to detect if they’ve done the trial or not (easily circumvented, but not by general users)

Probably a combination of a few of these would give what you want

[alfarez]

I like the cookie idea. Thanks.