Organization API key. Keys are prefixed with vk_live_ (production) or
vk_sandbox_ (sandbox).
Relationship type ID (crel_*).
API version date string (e.g. 2026-02-01). If omitted, the version
pinned to your API key is used.
Response key casing. Defaults to snake.
Machine-readable slug, unique per org/environment.
Human-readable label for the outgoing direction (what the related identity is to the source).
Label for the reverse direction. Equal to label for symmetric types.