Sample - Slack Web API
POST/reactions.add

Add an emoji reaction to an item

Adds an emoji reaction to a message or other supported item. Supply the channel, reaction name, and message timestamp to identify both the reaction and its target. Use an authentication token with the reactions:write scope to perform the operation.

  • RetriesRetries up to 2×, 500ms backoff, 30s timeout.

1 parameter · 3 body fields
tokenstringrequired
Authentication token with the `reactions:write` scope.

Form data identifying the target message and the emoji reaction to add.

channelstringrequired
Channel where the message to add reaction to was posted.
namestringrequired
Reaction (emoji) name.
timestampstringrequired
Timestamp of the message to add reaction to.

2 status codes
200Returns an object with `ok` set to true confirming that the reaction was added.
okbooleanrequired
Allowed:true
defaultReturned when the target message or channel cannot be found, the reaction name is invalid or already present, reaction limits are exceeded, or authentication, permission, or request arguments are invalid; the response includes `ok` set to false and an `error` reason.
callstackstringoptional
Note: PHP callstack is only visible in dev/qa
errorstringrequired
Allowed:bad_timestampmessage_not_foundno_item_specifiedinvalid_namealready_reactedtoo_many_emojitoo_many_reactionsnot_authedinvalid_authaccount_inactiveno_permissioninvalid_arg_name
okbooleanrequired
Allowed:false

Error handling

The token must include the reactions:write scope, and channel, name, and timestamp are all required. name must identify a valid reaction, while timestamp must identify the target message in the specified channel.