Thanks a lot for the constructive feedback. Noting them in down my priority list.

You're right, the most common use case would be that a client sends HTML instead of an URL to the endpoint. This way a PDF can be created of data that's not publicly exposed on the internet (think invoices, contracts, etc.)

I also don't store any of the data you send to the API, as to not further contribute to your GDPR nightmares.