API_REFERENCE.md

API Reference

HTTP Endpoints (API Gateway)

All endpoints are served by a single Lambda function. Slack sends requests to the /slack/* URLs after you configure the app. The /api/federation/* endpoints handle cross-instance communication for external connections.

Method	Path	Purpose
POST	/slack/events	Receives all Slack events (messages, actions, view submissions) and slash commands
GET	/slack/install	OAuth install page — redirects the user to Slack's authorization screen
GET	/slack/oauth_redirect	OAuth callback — Slack redirects here after the user approves the app
POST	/api/federation/pair	Accept an incoming external connection request
POST	/api/federation/message	Receive a forwarded message from a connected instance; resolves @ mentions and # channel references locally before posting
POST	/api/federation/message/edit	Receive a message edit from a connected instance; applies the same local mention and channel resolution before updating
POST	/api/federation/message/delete	Receive a message deletion from a connected instance
POST	/api/federation/message/react	Receive a reaction from a connected instance
POST	/api/federation/users	Exchange user directory with a connected instance
GET	/api/federation/ping	Health check for connected instances

Subscribed Slack Events

Event	Handler	Description
app_home_opened	handle_app_home_opened	Publishes the Home tab with workspace groups, channel syncs, and user matching.
member_joined_channel	handle_member_joined_channel	Detects when SyncBot is added to an unconfigured channel; posts a message and leaves.
message.channels / message.groups	respond_to_message_event	Fires on new messages, edits, deletes, and file shares in public/private channels. Dispatches to sub-handlers for new posts, thread replies, edits, deletes, and reactions.
reaction_added / reaction_removed	_handle_reaction	Syncs emoji reactions to the corresponding message in all target channels.
team_join	handle_team_join	Fires when a new user joins a connected workspace. Adds the user to the directory and re-checks unmatched user mappings.
tokens_revoked	handle_tokens_revoked	Handles workspace uninstall — soft-deletes workspace data and notifies group members.
user_profile_changed	handle_user_profile_changed	Detects display name or email changes and updates the user directory and mappings.