API Limits vs Attachments URL

Hello,
I know there is an API limit of 5req/s to query AirTable.

What about Attachments’ URL ?

  • Can I directly use a link to the attachment’s URL ?
    • is there a secret/token in the URL that should not be displayed ?
  • Is there a cache mechanism on AirTable side ?
  • Or should I download and cache the attachment ?