How to Draft Email Responses from Slack Messages with N8n

Dashboard > New Workflow

Create New Workflow

Start a fresh N8n workflow for the email drafting automation. This sets up your canvas for connecting Slack and OpenAI.

1. 1Click 'New Workflow' in the N8n dashboard
2. 2Name it 'Email Response Drafter'
3. 3Click 'Save' to create the workflow

Workflow > Add Node > Triggers > Slack

Add Slack Trigger

Set up a Slack trigger that listens for new messages in your designated channel. This monitors when someone pastes a client email.

1. 1Click the '+' button to add a node
2. 2Search for 'Slack' and select 'Slack Trigger'
3. 3Choose 'On New Message' from the trigger dropdown
4. 4Select your target channel from the Channel list

Slack Node > Credentials > Create New

Connect Slack Credentials

Authenticate N8n with your Slack workspace. You need a bot token with channels:read and channels:history permissions.

1. 1Click 'Create New' under Credentials
2. 2Select 'Slack OAuth2 API' from the dropdown
3. 3Paste your Bot User OAuth Token
4. 4Click 'Test' then 'Save'

Add Node > Logic > IF

Add Message Filter

Filter messages to only process ones containing email content. This prevents the workflow from running on casual chat messages.

1. 1Add an 'IF' node after Slack
2. 2Set condition to 'String' > 'Contains'
3. 3Set Value 1 to '{{$node["Slack Trigger"].json["text"]}}'
4. 4Set Value 2 to '@' (to detect email addresses)

Add Node > Helpers > Code

Extract Email Content

Parse the Slack message to extract the original email text. This cleans up the content before sending to OpenAI.

1. 1Add a 'Code' node on the 'true' path
2. 2Set Mode to 'Run Once for Each Item'
3. 3Paste email extraction code in the JavaScript field
4. 4Map input to Slack message text

Add Node > AI > OpenAI

Connect OpenAI

Add OpenAI credentials to enable GPT-4 access. You'll need an API key from platform.openai.com with sufficient credits.

1. 1Add an 'OpenAI' node after the Code node
2. 2Select 'Chat' operation
3. 3Click 'Create New' under Credentials
4. 4Paste your OpenAI API key and save

OpenAI Node > Messages > Add Message

Configure GPT-4 Prompt

Set up the prompt that instructs GPT-4 to draft a professional email response. This determines the tone and structure of generated replies.

1. 1Set Model to 'gpt-4' in the OpenAI node
2. 2Add a system message: 'You are a professional email assistant. Draft polite, concise responses.'
3. 3Set user message to include the extracted email content
4. 4Set Max Tokens to 300

Add Node > Helpers > Code

Format Response Output

Structure the GPT-4 response for clean display in Slack. This adds formatting and context around the drafted email.

1. 1Add another 'Code' node after OpenAI
2. 2Extract the response text from OpenAI output
3. 3Add formatting with headers and line breaks
4. 4Include original message context

Add Node > Communication > Slack

Send to Slack Thread

Post the drafted response as a thread reply to the original message. This keeps conversations organized and provides context.

1. 1Add a 'Slack' node set to 'Send Message'
2. 2Map Channel to the original channel
3. 3Set Thread TS to the original message timestamp
4. 4Map Text to your formatted response

Node Settings > On Error

Add Error Handling

Set up error handling for API failures and rate limits. This prevents the workflow from breaking when OpenAI is unavailable.

1. 1Click the OpenAI node settings gear
2. 2Set 'On Error' to 'Continue With Last Node'
3. 3Add an IF node to check for errors
4. 4Route errors to a Slack notification

Workflow > Test Workflow

Test the Workflow

Run a complete test with a real client email pasted in Slack. This verifies all connections and data mapping work correctly.

1. 1Click 'Test Workflow' in the top bar
2. 2Paste a sample client email in your Slack channel
3. 3Watch the workflow execution in real-time
4. 4Verify the response appears as a thread reply

Workflow > Active Toggle

Activate Production Mode

Enable the workflow to run automatically on new Slack messages. This makes the automation live for your team.

1. 1Click the toggle switch to 'Active'
2. 2Verify the status shows 'Active' with green indicator
3. 3Test with one more real message to confirm
4. 4Share the channel with your team

Drop this into an n8n Code node.

// Extract email body from Slack message
const message = $input.first().json.text;
const emailMatch = message.match(/From:[\s\S]*?(?=\n\n|$)/i);

// Extract email body from Slack message
const message = $input.first().json.text;
const emailMatch = message.match(/From:[\s\S]*?(?=\n\n|$)/i);
if (emailMatch) {
  return [{ json: { email_content: emailMatch[0], clean_text: emailMatch[0].replace(/^From:|^To:|^Subject:/gmi, '').trim() } }];
} else {
  return [{ json: { error: 'No email format detected' } }];
}