Slack integration

What it does

The Slack integration connects a Slack workspace so your workflows can post channel messages and direct messages, create and manage channels, look up users by email, upload and manage files, add reactions and pins, manage user groups, set status, and start a run when Slack delivers an event. Connect a workspace once and reuse the connection across any workflow.

Connect a Slack account

1. Open Connections in your workspace

   Open your workspace in TaskJuice and go to Connections.

2. Choose Slack and connect

   Choose Slack and click Connect. TaskJuice sends you to Slack to authorize the workspace.

3. Authorize as the workspace owner

   Sign in to Slack as your client, or have them complete the authorization in their own workspace. Slack asks them to approve the permissions TaskJuice requests to post messages, read and manage channels, look up users, read files, and add reactions.

4. Return to TaskJuice

   Slack returns you to the workspace with the connection ready to use in any workflow.

For the full connect flow, including how connections are scoped and reused, see Connect an account.

Add your signing secret for triggers

If you plan to start workflows from Slack events, you also need to paste your Slack signing secret into TaskJuice. TaskJuice verifies each incoming event with that secret so it only acts on deliveries that genuinely came from Slack.

Copy the value from your Slack app settings under Basic Information, Signing Secret, then paste it into the trigger configuration in TaskJuice. Deliveries with a timestamp older than 5 minutes are rejected.

Triggers

Slack has one trigger.

This is a single generic trigger that receives every event your Slack app subscribes to, in real time. There are no separate "new message" or "reaction added" triggers. To act on one specific event type, read event.type in the trigger output and route with a downstream Branch or Switch node.

Each delivery is one event, so every activation processes exactly one Slack event. There is no batched array to loop over.

Trigger output

The trigger output is the Slack Events API envelope. These top-level fields are always present.

Actions

Slack provides 53 actions across ten domains. All are HTTP-based and run on a connected Slack workspace. Channel, user, and user-group selectors are dropdowns backed by your live workspace; every dropdown also accepts an expression so you can compute the value from an upstream node.

Messaging

Channels

Users

Files

Reactions and pins

User groups

Status and presence

Search and reminders

Field notes

• Channel, user, and user-group fields are dropdowns backed by your live workspace: pick a channel, user, or user group by name and TaskJuice sends the ID. Toggle the {} expression escape to compute the value from an upstream node instead. To post to a private channel that is not in the dropdown, switch the field to expression mode and supply the channel ID.
• slack/send-direct-message: the recipient is a user picker. Slack posts to that user's direct-message channel.
• slack/invite-to-channel and slack/update-usergroup-members: users is a comma-separated list of user IDs (a multi-value field), so it stays a text field. Wire it from an upstream node or type the IDs directly.
• slack/add-reaction and slack/remove-reaction: name is an emoji name without colons, for example thumbsup or smile.
• Message-timestamp fields are named ts (Update / Delete Message), timestamp (reactions, pins), message_ts (Get Message Permalink), or channel_ts (Get Thread Replies).
• Uploading a file is a two-step flow: call Get Upload URL, PUT the file bytes to the returned upload_url with an HTTP node, then call Complete Upload with the files array. Slack retired the single-call files.upload method in March 2025.

Errors

Every Slack action and the channel dropdown map the provider's HTTP status to the same TaskJuice error codes. The default failure code is UPSTREAM_REQUEST_FAILED.

Known limitations

• not_in_channel on posts. A bot can only post to, or read the history of, a channel it belongs to. If a Send Message or history action fails with not_in_channel, run Join Channel first (the bot must be in the channel), then retry. This is the single most common Slack automation failure.
• ok: false fails the step. Slack returns HTTP 200 even when a call fails logically, for example on a missing scope or an invalid channel. TaskJuice reads the ok field rather than the HTTP status, so those replies fail the step with the PROVIDER_REPORTED_ERROR code and carry Slack's own reason (such as not_in_channel or missing_scope) in the error message. Handle them like any other step failure, with a per-node on-error policy or a downstream branch.
• User-token methods. Search Messages, Search Files, Create Reminder, List Reminders, Delete Reminder, and Set User Status require a user-token connection. On a bot-token connection they return ok: false with not_allowed_token_type.
• Tiered rate limits. Slack enforces its own per-method rate limits, grouped into tiers (roughly Tier 1 about 1 request/minute up to Tier 4 about 100+ requests/minute), plus a posting limit of about one message per second per channel. When Slack throttles a request it returns 429 with Retry-After, which TaskJuice classifies as a retryable RATE_LIMITED error and retries. These are Slack's limits, not TaskJuice's.
• File upload is a two-step flow. There is no single upload action (Slack retired files.upload in March 2025). Use Get Upload URL, PUT the bytes to the returned URL with an HTTP node, then Complete Upload. TaskJuice does not download file contents; Get File Info returns metadata only.
• Most action shapes are documented-shape. A core subset is verified live against a connected workspace: the OAuth connection, the channel, user, and user-group pickers, Get Channel, and Send Message all returned ok: true. Every other action follows Slack's official Web API method docs and is pending live curl-confirmation against a connected workspace.
• One generic event trigger. The Slack Event trigger receives every event your Slack app is subscribed to. Narrow to a specific event by branching on event.type downstream. There are no per-event-type triggers yet.
• Trigger signing. The trigger requires your Slack signing secret. TaskJuice rejects any delivery whose timestamp is older than 5 minutes.

Related

• Connect an account
• Triggers and actions
• Control flow nodes