emulate

Slack API

Fully stateful Slack Web API emulation with channels, messages, threads, reactions, user profiles, presence, modern file uploads, pins, bookmarks, views, OAuth v2, and incoming webhooks. Chat writes preserve common rich message fields such as blocks, attachments, metadata, formatting flags, unfurl flags, and client message ids. Conversation writes update archive state, names, topics, purposes, membership, DMs, MPIMs, and read cursors. User writes update profile fields, status, custom fields, and deterministic active or away presence. File writes support the current external upload flow with local upload URLs, file share messages, reads, lists, downloads, and deletes. Pin and bookmark writes support channel message pins and link bookmarks. View writes support App Home publishing and modal stacks. Seeded OAuth apps and OAuth installs create bot users and installation records. OAuth exchanges and explicit token seeds create scoped token records. State changes dispatch event_callback payloads to configured webhook URLs.

Auth

  • POST /api/auth.test - test authentication

Scope checks are relaxed by default for local development. Set slack.strict_scopes: true in seed config to make supported Web API methods return Slack-style missing_scope errors with needed and provided fields. Strict mode checks chat:write, channels:read, channels:history, channels:join, channels:manage, channels:write, groups:read, groups:history, groups:write, im:read, im:history, im:write, mpim:read, mpim:history, mpim:write, users:read, users:read.email, users.profile:read, users.profile:write, users:write, files:read, files:write, pins:read, pins:write, bookmarks:read, bookmarks:write, reactions:read, reactions:write, and team:read. Slack lists no method-specific scopes for views.publish, views.open, views.update, or views.push, so the emulator requires auth but does not add strict-scope checks for those methods.

Chat

  • POST /api/chat.postMessage - post message with text or rich payload fields (supports threads via thread_ts and DM user IDs)
  • POST /api/chat.postEphemeral - post ephemeral message outside channel history
  • POST /api/chat.update - update message text and rich payload fields
  • POST /api/chat.delete - delete message
  • GET /api/chat.getPermalink / POST /api/chat.getPermalink - get message permalink
  • POST /api/chat.scheduleMessage - schedule pending message
  • POST /api/chat.deleteScheduledMessage - delete pending scheduled message
  • POST /api/chat.scheduledMessages.list - list pending scheduled messages
  • POST /api/chat.meMessage - /me message

Conversations

  • POST /api/conversations.list - list conversations (cursor pagination, types, exclude_archived)
  • POST /api/conversations.info - get channel info
  • POST /api/conversations.create - create channel
  • POST /api/conversations.archive - archive channel
  • POST /api/conversations.unarchive - restore archived channel
  • POST /api/conversations.rename - rename channel
  • POST /api/conversations.setTopic - update channel topic
  • POST /api/conversations.setPurpose - update channel purpose
  • POST /api/conversations.history - channel history with rich message fields (top-level messages)
  • POST /api/conversations.replies - thread replies with rich message fields
  • POST /api/conversations.join - join channel
  • POST /api/conversations.leave - leave channel
  • POST /api/conversations.invite - invite user to a channel
  • POST /api/conversations.kick - remove user from a channel
  • POST /api/conversations.open - open or resume DM/MPIM
  • POST /api/conversations.close - close DM/MPIM
  • POST /api/conversations.mark - set read cursor
  • POST /api/conversations.members - list members

Users

  • POST /api/users.list - list users (cursor pagination)
  • POST /api/users.info - get user info
  • POST /api/users.lookupByEmail - lookup by email
  • GET /api/users.profile.get / POST /api/users.profile.get - get user profile fields
  • POST /api/users.profile.set - update profile fields, status, and custom fields
  • GET /api/users.getPresence / POST /api/users.getPresence - get active or away presence
  • POST /api/users.setPresence - set the authed user to away or automatic presence

Reactions

  • POST /api/reactions.add - add reaction
  • POST /api/reactions.remove - remove reaction
  • POST /api/reactions.get - get reactions for a message

Files

  • POST /api/files.getUploadURLExternal - create a local external upload session
  • POST /upload/v1/:fileId - receive raw uploaded file bytes
  • POST /api/files.completeUploadExternal - complete uploads and optionally share file messages
  • GET /api/files.info / POST /api/files.info - get file metadata
  • GET /api/files.list / POST /api/files.list - list completed files
  • GET /files-pri/:fileId/:filename - download file bytes with a bearer token that can access the file
  • POST /api/files.delete - delete a completed file

Pins And Bookmarks

  • POST /api/pins.add - pin a message to a channel
  • GET /api/pins.list / POST /api/pins.list - list pinned message items for a channel
  • POST /api/pins.remove - remove a message pin from a channel
  • POST /api/bookmarks.add - add a link bookmark to a channel
  • POST /api/bookmarks.edit - update a link bookmark
  • POST /api/bookmarks.list - list channel bookmarks
  • POST /api/bookmarks.remove - remove a bookmark from a channel

Views

  • POST /api/views.publish - publish or update an App Home view for a user
  • POST /api/views.open - open a modal view
  • POST /api/views.update - update a view by view_id or external_id
  • POST /api/views.push - push a modal view onto the current modal stack
  • POST /api/views.generateTriggerId - local helper for tests that need a modal trigger id

Modal opens and pushes require values from /api/views.generateTriggerId. Pass the returned value as trigger_id or interactivity_pointer; generate push values with an existing view_id and use them within 3 seconds.

Team

  • POST /api/team.info - get workspace info

Bots

  • POST /api/bots.info - get bot info

Incoming Webhooks

  • POST /services/:teamId/:botId/:webhookId - post text or rich payload fields via incoming webhook (supports channel override and thread_ts)

OAuth

  • GET /oauth/v2/authorize - authorization endpoint (shows user picker)
  • POST /oauth/v2/authorize/callback - local user picker callback that creates the auth code
  • POST /api/oauth.v2.access - token exchange

Inspector

  • GET / - tabbed local inspector for conversations, messages, files, views, auth records, incoming webhooks, event subscriptions, and event deliveries

oauth.v2.access returns a bot token, bot_user_id, app_id, team details, and the authed_user object. When user_scope is requested, authed_user also includes a user token and granted user scopes.

Event Dispatching

When supported Slack writes mutate state, the emulator dispatches event_callback payloads to configured webhook URLs matching Slack's Events API format:

  • message events on chat.postMessage
  • message with subtype: message_changed on chat.update
  • message with subtype: message_deleted on chat.delete
  • rich message fields are included on posted message events when present
  • reaction_added / reaction_removed events on reactions.add / reactions.remove
  • pin_added / pin_removed events on pins.add / pins.remove
  • message with subtype: bot_message on incoming webhook posts
  • channel_archive / channel_unarchive for public lifecycle archive writes
  • group_archive / group_unarchive for private lifecycle archive writes
  • channel_rename / group_rename and matching name message subtypes on conversations.rename
  • message with public channel_topic / channel_purpose or private group_topic / group_purpose subtypes on topic and purpose writes
  • member_joined_channel / member_left_channel on invite, join, leave, and kick writes
  • im_created, im_open, im_close, im_marked, and group open/close/marked events for DM and MPIM writes
  • user_change on profile writes
  • presence_change on presence writes
  • file_created, file_shared, and file_deleted on file writes
  • message with subtype: file_share on shared file uploads

Current Limits

Slack Connect, Enterprise Grid admin APIs, Audit Logs API, SCIM, Legal Holds, Socket Mode, slash command and interaction simulation, user groups, reminders, stars, calls, canvases, lists, functions, workflows, chat streaming, legacy files.upload, exact rate limiting, and paid-plan behavior are not implemented.