Add reaction to existing posts or comments

Question

How can we "like" or add other reactions to someone else's channel message or comment via the Graph API?

Answer 1

Update: We reached out to MS Support and received the following info: "The API to reply to a message using a POST /replies request is solemnly for issuing a reply to a message, and not to edit the status of the parent message itself. Moreover, the "update chatMessage" API which is a PATCH /messages and which is the only API to edit a parent message only supports updating the policyViolation property of a chatMessage. Essentially, there is currently no documented API / already-present API examples on how to add a reaction, making this purely unsupported."

Answer 2

I've not done this myself, but it certainly looks possible. You need to reply to the message, as per https://learn.microsoft.com/en-us/graph/api/channel-post-messagereply?view=graph-rest-1.0&tabs=http and notice that it has a "reactions" collection. That would be populated with a chatMessageReaction type, as per https://learn.microsoft.com/en-us/graph/api/resources/chatmessagereaction?view=graph-rest-beta

Note of warning: chatMessageReaction is a beta type though, so just be aware you need to call the beta endpoint, and it has a risk to use in production code as things might change.