Surfaces

The surface field in the payload describes where the user interaction happened — for example in the feed on a cast, or outside cast context.

Clients MUST include surface on every authenticated submit (see Actions — submit).

Discriminated shape

surface is a discriminated object on type:

`surface.type`	Meaning
`standalone`	not tied to a specific cast (e.g. opened in an emulator).
`cast`	interaction in a cast context

"surface": {
  "type": "standalone"
}

"surface": {
  "type": "cast",
  "cast": {
    "hash": "0xb79dbbc1a9f31365f8c4f722c4a6c5a6b7c8d9e0",
    "author": {
      "fid": 67890
    }
  }
}

For a client-side upgrade checklist and TypeScript-oriented examples, see Upgrading from v1.0 (clients).