Slack Customize Url Unfurl

Link source: either 'composer' or 'conversations_history'. Must be provided with `unfurl_id`.

Channel, private group, or DM channel to send message to. Can be an encoded ID, or a name. Must be provided with `ts`, or alternatively provide `unfurl_id` and `source` together.

JSON string mapping URLs to custom unfurl content (Slack attachment format or blocks). Pass as a plain JSON string (not URL-encoded). To remove an existing unfurl, provide an empty object for that URL.

JSON object with 'entities' field providing Work Object array. Either `unfurls` or `metadata` is required. Pass as a JSON string.

Link ID to unfurl. Must be provided with `source`. Alternative to using `channel` and `ts` parameters.

URL-encoded custom URL for user authentication with your app to enable unfurling. Used when `user_auth_required` is true.

JSON array of structured blocks (URL-encoded) sent as ephemeral authentication invitation. Alternative to `user_auth_message` for richer formatting. Used when `user_auth_required` is true.

Ephemeral message text prompting user authentication with your app for domain-specific unfurling. Used when `user_auth_required` is true and authorization is pending.

Set to `true` if user authentication is required to unfurl links for a domain, enabling an authentication flow using `user_auth_url` and `user_auth_message`.