How to Run Sentiment Analysis on Slack Messages with Zapier

Dashboard > Create Zap > Trigger

Create New Zap with Slack Trigger

Start a new Zap and set up Slack as the trigger to monitor your feedback channel. This will fire every time someone posts a new message in the specified channel.

1. 1Click 'Create Zap' from the Zapier dashboard
2. 2Search for 'Slack' and select it as your trigger app
3. 3Choose 'New Message Posted to Channel' as the trigger event
4. 4Click 'Continue' to move to the account connection

Trigger > Account

Connect Your Slack Account

Authenticate Zapier to access your Slack workspace. You'll need admin permissions to set up channel monitoring.

1. 1Click 'Sign in to Slack' button
2. 2Select your workspace from the dropdown
3. 3Click 'Allow' to grant Zapier permissions
4. 4Confirm the green 'Connected' status appears

Trigger > Event

Configure Channel Settings

Point the trigger to your specific feedback channel. The trigger will only fire for messages in this channel, ignoring DMs and other channels.

1. 1In the 'Channel' dropdown, select your #feedback channel
2. 2Leave 'Trigger for Bot Messages' unchecked
3. 3Set 'Include Threaded Messages' to 'No' to avoid analyzing replies
4. 4Click 'Continue' to proceed

Trigger > Test

Test Slack Trigger

Zapier will fetch a recent message from your feedback channel to use as test data. This sample will flow through the rest of your Zap setup.

1. 1Click 'Test trigger' button
2. 2Wait for Zapier to fetch recent messages
3. 3Review the sample message data in the results panel
4. 4Click 'Continue with selected record' if the data looks correct

Action > Choose App

Add OpenAI Action Step

Add OpenAI as the action step to analyze the sentiment of each Slack message. This will send the message text to GPT for classification.

1. 1Click the '+' button to add an action step
2. 2Search for 'OpenAI' and select it
3. 3Choose 'Send Prompt' as the action event
4. 4Click 'Continue' to move to account setup

Action > Account

Connect OpenAI Account

Link your OpenAI account using an API key. You'll need an active OpenAI account with API credits to run sentiment analysis.

1. 1Click 'Connect a new account'
2. 2Go to platform.openai.com/api-keys in a new tab
3. 3Create a new API key and copy it
4. 4Paste the API key into Zapier's connection field
5. 5Click 'Yes, Continue' after successful connection

Action > Event > Model Settings

Configure GPT Prompt Settings

Set up the GPT model and parameters for sentiment analysis. Use GPT-3.5-turbo for speed and cost efficiency on this straightforward classification task.

1. 1Select 'gpt-3.5-turbo' from the Model dropdown
2. 2Set Max Tokens to 50 (enough for 'positive', 'neutral', or 'negative')
3. 3Set Temperature to 0.1 for consistent classifications
4. 4Leave Top P at default (1)

Action > Event > Messages

Build the Sentiment Analysis Prompt

Create a specific prompt that instructs GPT to classify the message sentiment. Include the Slack message text as dynamic data from the trigger.

1. 1Click in the 'User' message field
2. 2Type: 'Analyze the sentiment of this message and respond with only one word: positive, negative, or neutral. Message: '
3. 3Click the data pill icon and select 'Text' from the Slack trigger data
4. 4Add a closing quote after the Text field

Action > Test

Test OpenAI Action

Run the sentiment analysis on your sample Slack message to verify GPT returns the expected classification format.

1. 1Click 'Test step' button
2. 2Wait for OpenAI to process the request
3. 3Check that the response contains only 'positive', 'negative', or 'neutral'
4. 4Click 'Continue' if the classification looks correct

Action 2 > Choose App

Add Slack Reply Action

Set up a second Slack action to post the sentiment classification back to the feedback channel. This creates a thread reply under the original message.

1. 1Click '+' to add another action step
2. 2Select Slack as the app
3. 3Choose 'Send Channel Message' as the action
4. 4Use your existing Slack connection

Action 2 > Event

Configure Reply Message

Set up the message content and targeting to reply in the same channel with the sentiment analysis result.

1. 1Select your #feedback channel from the Channel dropdown
2. 2In the Message Text field, type 'Sentiment: ' followed by the OpenAI content data pill
3. 3Set Thread Timestamp to the original message timestamp from the trigger
4. 4Leave other fields at defaults

📬 New entry: {{1.name}}
Email: {{1.email}}
Details: {{1.description}}

Action 2 > Test

Test Complete Workflow

Run the full Zap end-to-end to verify sentiment analysis and Slack reply work together correctly.

1. 1Click 'Test step' on the final Slack action
2. 2Check your #feedback channel for the sentiment reply
3. 3Verify the reply appears as a thread under the original message
4. 4Click 'Publish Zap' if everything works correctly

Drop this into a Zapier Code step.

{{if(length(trigger.text) > 10 && not(contains(trigger.user, 'bot')), 'process', 'skip')}}

{{if(length(trigger.text) > 10 && not(contains(trigger.user, 'bot')), 'process', 'skip')}}