I can add bookmarks in a Slack channel manually, by clicking on "Add Bookmark". I will be prompted for the link, as shown in the below modal:
I wish to add this via the Slack API methods, but I cannot seem to find an API for this. Has Slack published an API for this? If not, is there a way to do this via other methods in the Slack API?
As of March,2022
Slack have officially launched APIs for bookmarks
API for Adding Bookmarks in slack channel
https://api.slack.com/methods/bookmarks.add
Earlier:
Currently slack does not have any publicly exposed methods for adding bookmarks.
Internally, slack uses https://**slackdomain**.slack.com/api/bookmarks.add
along with form data & browser cookies, to add new bookmarks.