Send Slack File

The Send Slack File activity sends a file to a Slack channel as part of your workflow.

Purpose

Use the Send Slack File activity to:

• Share report outputs with team channels
• Distribute generated files to stakeholders
• Send workflow results or exports
• Automate file delivery to Slack

Prerequisites

Slack Connection Required

• Must have a configured Slack connection (see Settings → Connections)
• OAuth token must have files:write permission

File Source

Files are typically generated by previous workflow activities, such as:

• Report book results (PDFs, Excel files)
• Exported data files
• Generated documents

Configuration

Connection Settings

• Slack Connection: Select a pre-configured Slack connection

Channel Settings

• Channel Name: The Slack channel to send to (e.g., "products")
• Channel ID: Alternative to channel name

Message Settings (Optional)

• Message: Optional text message to accompany the file
• Appears above the file in Slack
• Can include workflow parameters

File Settings

• File Source: Select the file to send
• Typically uses output from a previous workflow activity

Context Variable (Optional)

• Message Timestamp: Store the timestamp of the message with the file
• Can be used to track the upload or read responses

File Source Options

Report Book Result

Most common use case - sending generated reports:

File Source: Report Book Result
  └─ Select from previous Report Book activity output

Workflow File

Files stored or generated within the workflow:

File Source: Workflow File
  └─ Select from File Explorer or previous activity

Example Configurations

Send Report PDF

Slack Connection: Company Slack
Channel: reports
Message: Monthly report for {MonthName} - generated {GenerationDate}
File: Report Book Result (Monthly_Report.pdf)

Send Data Export

Slack Connection: Company Slack
Channel: data-team
Message: Client data export - {RecordCount} records
File: Export Result (ClientData.xlsx)

Send Generated File with Timestamp

Slack Connection: Company Slack
Channel: finance
Message: Financial summary for {Period}
File: Report Book Result (Finance_Summary.pdf)
Timestamp Context Key: FileUploadTimestamp

Common Use Cases

Automated Report Distribution

1. Generate Report Book (PDF/Excel)
2. Send Slack File
   └─ Channel: reports
   └─ File: Report Book Result
   └─ Message: "{ReportName} for {Period}"

Data Export Delivery

1. Export Data to File
2. Send Slack File
   └─ Channel: data-exports
   └─ File: Export File
   └─ Message: "Daily export completed"

Error Logs

1. Generate Error Report
2. Send Slack File
   └─ Channel: alerts
   └─ File: Error Log
   └─ Message: "⚠️ Workflow errors for {Date}"

Scheduled Deliveries

Workflow Schedule: Daily at 8 AM
  └─ Generate Report
  └─ Send Slack File
      └─ Channel: morning-reports
      └─ Message: "Good morning! Here's today's report."

Supported File Types

Slack generally supports:

• Documents: PDF, DOCX, TXT, MD
• Spreadsheets: XLSX, CSV
• Images: PNG, JPG, GIF
• Archives: ZIP
• Other: Most common file formats

Check Slack's current file size limits (typically 1 GB for free plans, may vary).

Message Formatting

The accompanying message supports:

• Plain text
• Workflow parameters: {ParameterName}
• Emojis: 📊 📈 📉
• Simple formatting (Slack auto-detects URLs)

Note: For advanced markdown formatting, use Send Slack Message activity separately.

File Naming

• Files retain their original names from the source activity
• Report Book Results use the report book's configured file name
• Consider configuring meaningful file names in report book settings

Best Practices

• Clear Messages: Provide context about the file content
• Appropriate Channels: Send to relevant team channels
• Naming Convention: Use consistent, descriptive file names
• Size Awareness: Be mindful of large files (consider compression)
• Frequency: Avoid overwhelming channels with too many files
• Test Channel: Test deliveries in a private channel first
• Error Handling: Plan for file generation failures

Usage Pattern with Report Books

Complete Report Delivery Flow

1. Report Book Activity
   └─ Generate: Monthly_Report
   └─ Format: PDF
   └─ Store Output: MonthlyReportFile

2. Send Slack File
   └─ Connection: Company Slack
   └─ Channel: management
   └─ Message: "📊 Monthly Report - {MonthName} {Year}"
   └─ File: MonthlyReportFile

3. Email Activity (parallel)
   └─ Also send via email to external stakeholders

Context Variable Usage

Store the message timestamp to:

• Track successful uploads
• Read responses about the file
• Link multiple messages together
• Implement approval workflows based on file reviews

Timestamp Context Key: ReportUploadTimestamp

Later activities can reference: {ReportUploadTimestamp}

Limitations

• One File per Activity: Sends one file at a time
• File Size: Subject to Slack's file size limits
• Source Dependency: File must be generated by a previous activity
• No Direct Upload: Cannot upload files from external sources directly

To send multiple files:

• Use multiple Send Slack File activities
• Or combine files into a ZIP archive first

Troubleshooting

File Not Appearing in Slack

• Verify OAuth token has files:write permission
• Check bot is added to the target channel
• Confirm file was successfully generated by previous activity
• Review workflow execution log for errors
• Verify file size is within Slack limits

Wrong File Sent

• Check file source configuration
• Verify correct previous activity is referenced
• Ensure file variable is populated

Channel Not Found

• Verify channel name is correct (case-sensitive)
• Confirm bot is a member of the channel
• Try using Channel ID instead of name

OAuth Token Setup

Your IT team or Slack admin needs to add permissions:

Required Scopes:

• files:write - Upload and send files
• channels:read - Read channel information
• chat:write - Post messages (for accompanying text)

Setup Steps:

1. Go to Slack App settings
2. Navigate to OAuth & Permissions
3. Add Bot Token Scopes listed above
4. Reinstall app to workspace
5. Invite bot to target channels

Security Considerations

• Files uploaded to Slack are stored in Slack's systems
• Consider data sensitivity before automated uploads
• Review Slack's data retention policies
• Monitor file sharing for compliance requirements
• Restrict bot access to appropriate channels only
• Consider encrypting sensitive files before upload

JSON Reference

{
  "discriminator": "SendSlackFileWorkflowActivity",
  "activityId": "<uuid>",
  "name": "Send Slack File",
  "positionX": 0,
  "positionY": 0,
  "advanceRule": 2,
  "dataSource": "MySlackConnection",
  "channel": "reports",
  "message": "Monthly report for {MonthName}",
  "fileSystemPath": "/Reports/MonthlyReport.pdf",
  "isMarkdown": false,
  "responseTimestampContextKey": "FileUploadTimestamp"
}

Property	Type	Description
dataSource	string	Corresponds to the Slack Connection field. The name of the configured Slack data source.
channel	string	Corresponds to the Channel Name field. The Slack channel to send the file to. Supports {variable} interpolation.
message	string	Corresponds to the Message field. Optional text message accompanying the file. Supports {variable} interpolation.
fileSystemPath	string	Corresponds to the File Source field. The Una file system path of the file to upload.
isMarkdown	boolean	When true, the message is formatted as Markdown; otherwise plain text.
responseTimestampContextKey	string	Corresponds to the Message Timestamp context variable key. Workflow context key where the Slack message timestamp is stored after upload.

Alternative Approaches

Large Files

For very large files, consider:

• Generating a download link instead
• Using cloud storage (SharePoint, OneDrive)
• Sending email with attachment
• Compressing files before sending

External Recipients

For recipients outside Slack:

• Use Email activity instead
• Or combine: Send Slack File to internal team, Email to external
• Consider access controls and sharing permissions