Features

Reactions

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Reactions

Emoji reactions are a (message_id, user_id, emoji) triple. One reaction per user per emoji per message.

#Message controls

A mouse or trackpad reveals message actions on hover, including on touch-first tablets and embedded conversations. Touch input keeps the long-press action sheet. Switching between a trackpad and a finger updates those controls without reloading.

Adding a reaction brings its chip into view immediately. Scrolling while the request is pending keeps the position you chose.

#Endpoints

POST   /api/messages/{message_id}/reactions
DELETE /api/messages/{message_id}/reactions/{emoji}

POST body: {"emoji":"👀"}. Both endpoints require workspace membership for the message's workspace. Adding twice is a no-op that returns HTTP 200 without an event; removing a missing reaction is a no-op. Mutation responses include an event object and the message's complete aggregated reaction summaries. The event fields are empty on a no-op for compatibility with the existing mutation response shape.

Message reads expose reactions as per-emoji summaries:

{"emoji":"🦞","count":3,"reacted_by_me":true}

The API does not include the individual reacting users in message payloads.

#Events

  • reaction.added on add
  • reaction.removed on remove

The event payload contains {message_id, emoji, user_id, count} and inherits the message's channel_seq. count is the authoritative total for that emoji after the mutation, so realtime clients do not need to refetch the message.

An event from another user establishes the count, but does not establish the viewer's own reaction flag. When an event arrives before a history page, the web client combines that newer count with the page's viewer flag unless an own-user event or a zero count has already established the flag. Authoritative reconnects discard cached reactions and hydrate roots and replies from each fresh snapshot page; ordinary pages preserve newer realtime state.

#Storage

Reactions are stored and compared as exact strings; there is no allowlist or shortcode conversion. Bots should send the same Unicode glyph as the web picker (for example, 👀, 👍, or 🦞) to share its reaction count. eyes, :eyes:, and 👀 are three separate reactions, and custom strings render literally.

To remove a reaction, URL-encode its exact string once as a path segment. For example, % becomes %25, / becomes %2F, and the literal string %2F becomes %252F. The SDK handles this encoding in removeReaction.