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ActionSlackUpdated June 2026

How do I add an emoji reaction to a Slack message?

Short answer: You can add reaction in Slack by hand from its own interface, but it won’t repeat itself. On TinyCommand, add the Slack Add Reaction action to a workflow, map its 3 inputs from any upstream app, and it runs automatically every time the trigger fires. No code, and a free tier to start.

Add Reaction in Slack — start free All 45 Slack actions
Add Reaction in Slack — start free
Inputs

The fields this action accepts.

Every field can be mapped from an upstream trigger, AI step, table row, or hard-coded literal.

FieldTypeRequiredDescription
Channel
channel
stringRequiredSlack channel ID (starts with C for public, G for private group, D for DM). Find via List Channels. Not the channel name with #.
Message Timestamp
timestamp
stringRequiredThe 'ts' value of the message to react to
Emoji Name
name
stringRequiredEmoji name without colons (e.g. thumbsup, not :thumbsup:)
Sample request
{
  "channel": "C1234567890",
  "timestamp": "1234567890.123456",
  "name": "e.g. thumbsup"
}
Returns
{
  "ok": true
}

Use these fields in downstream nodes for routing, logging, or error handling.

Triggered by

Apps that pair well as the trigger for Add Reaction.

Any of these apps can fire this action as part of a workflow.

Gmail → Slack
1 Gmail triggers
Google Sheets → Slack
2 Google Sheets triggers
HubSpot → Slack
18 HubSpot triggers
Stripe → Slack
10 Stripe triggers
FAQ

Questions about Add Reaction.

What does the Add Reaction action do in Slack?
Adds an emoji reaction to a Slack message. Lightweight ack mechanism for bots, or used to seed a reaction-voting message.
What inputs does Add Reaction require?
Required: Channel, Message Timestamp, Emoji Name. Every input accepts a static value or a variable from any upstream node in your workflow.
Can I use dynamic inputs from earlier workflow nodes?
Yes. Any field on this action can pull values from upstream nodes, whether that's a form response, a trigger payload, an AI output, or a lookup result.
What happens if Slack returns an error?
The workflow pauses on the failed node, the error message is captured in the run log, and you can retry the run with one click. Auto-retry policies are configurable per workflow with exponential backoff up to 5 attempts.
Does Add Reaction support batch operations?
Yes. Run Add Reaction inside a Loop node to process arrays. TinyCommand handles Slack's rate limits automatically so you don't have to throttle manually.
More actions

Other Slack actions.

Action
Raw API Request
Makes a raw authenticated call to any Slack Web API method. The escape hatch for endpoints not yet covered by a dedicated action.
Action
Archive Channel
Archives a Slack channel. Members are removed and the channel becomes read-only but recoverable; the soft alternative to deleting.
Action
Cancel Scheduled Message
Cancels a previously-scheduled Slack message before it's sent. Use it when conditions change after a Schedule Message action ran.
Action
Create Canvas
Creates a new Slack Canvas, a rich-text doc that can be shared in channels. Useful for templated onboarding docs or recurring meeting agendas.
Action
Create Channel
Creates a new Slack channel with a name and is_private flag. Used for templated channel provisioning (per-customer support channel, per-incident war room).
Action
Delete File
Permanently deletes a file from Slack by file ID. Used for cleanup or DLP-driven removal of sensitive content.
Add Reaction in Slack — start free