type: string

description: >-
  A [signed link](#section/Asset-URLs) served over HTTPS. The link returned will expire in 30 days
  to prevent mis-sharing. Each time a GET request is initiated, a new signed URL
  will be generated.

pattern: '^https://lob-assets\.com/(letters|postcards|bank-accounts|checks|self-mailers|cards)/[a-z]{3,4}_[a-z0-9]{15,16}(\.pdf|_thumb_[a-z]+_[0-9]+\.png)\?(version=[a-z0-9-]*&)?expires=[0-9]{10}&signature=[a-zA-Z0-9-_]+$'