I’m writing a proposal for this project to apply for GSOC 16 and would like your help since I’m not completely familiarized with Discourse and its code.
The settings page will be close the one GitHub has, admins will be able to create webhooks by defining the payload URL and the events that trigger the webhook. After a webhook is created, there will be options to enable/disable, edit or remove it.
I’m thinking that each payload will have two sections: the first defines the payload with some fields like the timestamp and action that triggered the event; the second section contains the fields specific to each action.
Regarding the second section, we can use the existing serializers for the object(s) in question (user, topic, post, etc.) or we can choose carefully which fields will be sent.
Just to start the discussion, I’ve made a quick list of the proposed fields of each payload:
User
user_registered and user_activated
username, email, name, trust_level
trust_level_changed
username, old_trust_level, new_trust_level
message_sent
sender_username, receiver_username, msg_title, msg_content
Do we want the message content to be sent?
Another option is to define the required information of a user and use it whenever we’re referring to a user. For example, instead of sender_username we would have sender_info which has {ID, name, username, email, trust_level, …}.
Topic
Topic_created
ID, title, content, creator_username, categories
Topic_liked
ID, title, username, number_of_likes
Topic_{pinned,unpinned,archived,closed,invisibled,bookmarked}
ID, title, username
Post
Post_liked
post_ID, topic_ID, username, number_of_likes
Reply_posted
post_ID, topic_ID, username, content
Other
Auto_close_set
I don’t know what this one means…
Flag_raised
post_id, topic_id, reason
This is what I had in mind, please let me know if you had another idea 
