How to Integrate Retool with Slack

Open Retool and navigate to the Resources tab in the left sidebar (or go to your Retool home page and click Resources in the top navigation). Click the blue Add Resource button in the top right corner. In the resource type selector, scroll to the Communication section or use the search bar to find 'Slack'. Click the Slack option to open the configuration panel. You will see a configuration form with a Name field and an OAuth 2.0 Connect button. Give your resource a descriptive name like 'Slack - Production' or 'Slack Workspace'. Click the orange Connect with Slack button. A Slack OAuth consent screen opens in a new browser tab or popup window, listing the permissions Retool is requesting: posting messages, reading channel lists, and uploading files. Select the Slack workspace you want to connect from the dropdown at the top-right of the OAuth screen, then click Allow. Slack redirects back to Retool with a success confirmation and the resource configuration panel now shows a green 'Connected' badge. Under the Advanced options, you can optionally check 'Share OAuth 2.0 credentials between users' — enable this if you want all Retool users to post as a single shared bot identity rather than each user authenticating individually with their own Slack account. For operational alert apps, shared credentials are usually the right choice. Click Save Changes to finalize the resource.

Open or create a Retool app. In the bottom panel, click the + New button to create a new query. In the query configuration panel, select your Slack resource from the Resource dropdown. The query editor switches to show a Slack-specific interface with an Action Type dropdown. Click the Action Type dropdown and review the available operations: Post Message, List Channels, Upload File, Add Reaction, Get Channel Info, List Users, and more. Select Post Message to configure a message send operation. Fill in the required fields that appear: - Channel: Enter the channel name (e.g., #alerts) or a channel ID. You can hard-code a channel name or reference a Retool component with {{ select1.value }} to make it dynamic. - Message: Enter the message text. You can use Slack's mrkdwn formatting: *bold*, _italic_, `code`, and >blockquote. Use {{ }} expressions to include dynamic data from other queries or components, for example: 'New escalation: Order {{ table1.selectedRow.order_id }} from customer {{ table1.selectedRow.customer_email }} needs review.' - Optionally, expand the Advanced section to set a custom Bot Username (displayed sender name) and Bot Icon Emoji (e.g., :bell: for a notification bot). Set the query's Trigger mode to Manual (not Auto) since you only want messages sent when an action occurs, not on every app load. Click Run to test the query — switch to your Slack workspace and verify the message arrived in the target channel with the correct formatting and dynamic values.

Now wire the Slack message query to a user interaction in your Retool app. In the Component panel on the left sidebar, drag a Button component onto the canvas. Click the button to open its configuration in the right-side Inspector panel. In the Inspector, find the Interaction section and click Add Event Handler. In the event handler configuration: - Event: select 'Click' (this is the default) - Action: select 'Trigger query' - Query: select your Slack post message query from the dropdown This creates a direct link so that every time a user clicks the button, the Slack query runs and posts the configured message. You can also add a second event handler after the Slack query succeeds — for example, triggering a database update query to log that the notification was sent, or showing a success notification using the 'Show notification' action with message 'Slack alert sent successfully'. For additional safety on destructive or high-impact actions, enable the Confirm before running toggle in the button's Interaction section. This shows a confirmation modal before the query executes. Customize the confirmation message to say something contextual like 'Post escalation alert to #operations-alerts?' so users clearly understand what will happen. Test the full flow: click the button in your app, confirm the action if prompted, and verify the Slack message arrives in the target channel. Check the query run history in the bottom panel to see the execution status and any error details.

If your app needs to let users choose which Slack channel to post to rather than hard-coding a destination, create a separate query that fetches the list of available channels. In the query editor, create a new Slack query and set Action Type to List Channels. This returns all channels in your Slack workspace that the OAuth app has access to. In the Advanced tab of this query, enable Run this query automatically when inputs change and set the Trigger to On page load. This ensures the channel list is loaded as soon as the app opens. Next, drag a Select component from the Component panel onto the canvas. In the component's Inspector, set: - Data source: {{ listChannelsQuery.data }} (replace with your actual query name) - Label: {{ self.name }} — uses the 'name' field from the Slack API response (the channel name like 'general', 'alerts') - Value: {{ self.id }} — uses the channel's Slack ID (recommended over name for reliability) Now update your Post Message query's Channel field to reference the Select component: {{ channelSelect.value }}. When users pick a channel from the dropdown, the Slack message query dynamically targets that channel. This pattern is useful for apps where different team members route alerts to different channels based on context.

1// JavaScript transformer to format channel list for a Select component
2// Add this as a query transformer on the List Channels query
3const channels = data; // raw Slack API response
4return channels
5  .filter(ch => !ch.is_archived) // exclude archived channels
6  .sort((a, b) => a.name.localeCompare(b.name)) // alphabetical order
7  .map(ch => ({
8    label: '#' + ch.name,
9    value: ch.id,
10    is_private: ch.is_private
11  }));

For automated, scheduled notifications that run independently of any user being logged into the Retool app, use Retool Workflows. Navigate to the Workflows section in the Retool home page sidebar (look for the lightning bolt icon or 'Workflows' label). Click New Workflow to open the Workflow canvas. Click Add Trigger at the top of the canvas and select Schedule. Configure the schedule: select a frequency (Every day, Every week, or custom cron expression). For a daily 9 AM report, select 'Every day' and set the time to 09:00 in your appropriate timezone. A workflow can have multiple schedule triggers, so you could also add a Monday-specific trigger for a weekly summary. Click the + button to add the first block after the trigger. Select Resource Query block, then configure it: - Resource: your database (e.g., PostgreSQL resource) - Query: write the SQL to fetch the metrics you want to report Add a second block after the database query. Select Resource Query block again, this time choosing your Slack resource. Set Action Type to Post Message. In the Message field, reference the data from the first block using the block name syntax: 'Daily summary: {{ block1.data[0].total_signups }} new signups, ${{ block1.data[0].revenue }} revenue today.' Click Publish Release to activate the workflow. The schedule trigger will fire automatically at the configured time, run the database query, and post the Slack message — no user interaction required. Check the Runs tab in the Workflow editor to monitor execution history and debug any errors.

1-- SQL query for the database block in the Workflow
2-- Fetches yesterday's key metrics for the daily Slack digest
3SELECT
4  COUNT(CASE WHEN DATE(created_at) = CURRENT_DATE - 1 THEN 1 END) AS new_signups,
5  COALESCE(SUM(CASE WHEN DATE(created_at) = CURRENT_DATE - 1 THEN amount END), 0) AS revenue,
6  COUNT(CASE WHEN DATE(cancelled_at) = CURRENT_DATE - 1 THEN 1 END) AS cancellations
7FROM users
8LEFT JOIN orders ON users.id = orders.user_id;