Create Structured Logging System with Supabase and Log4j2-style Levels

Create centralized, structured logs directly from your n8n workflows, using Supabase as your scalable log database.

Whether you're debugging a workflow, monitoring execution status, or tracking error events, this template makes it easy to log messages in a consistent, structured format inspired by Log4j2 levels (DEBUG, INFO, WARN, ERROR, FATAL).

You’ll get a reusable sub-workflow that lets you log any message with optional metadata, tied to a workflow execution and a specific node.

What this template does

• Provides a sub-workflow that inserts log entries into Supabase.

• Each log entry supports the following fields:

  • workflow_name: Your n8n workflow identifier
  • node_name: last executed node
  • execution_id: n8n execution ID for correlation
  • log_level: One of DEBUG, INFO, WARN, ERROR, FATAL
  • message: Textual message for the log
  • metadata: Optional JSON metadata (flexible format)

• Comes with examples for diffrerent log levels:
  Easily call the sub-workflow from any step with a Execute Workflow node and pass dynamic parameters.

Use Cases

• Debug complex workflows without relying on internal n8n logs.
• Catch and trace errors with contextual metadata.
• Integrate logs into external dashboards or monitoring tools via Supabase SQL or APIs.
• Analyze logs by level, time, or workflow.

Requirements

To use this template, you'll need:

• A Supabase project with:
  • A log_level_type enum
  • A logs table matching the expected structure
• A service role key or supabase credentials available in n8n.

The table shema and SQL scripts are given in the template file.

How to Use This Template

• Clone the sub-workflow into your n8n instance.

• Set up Supabase credentials (in the Supabase node).

• Call the sub-workflow using the Execute Workflow node.

• Provide input values like:

  { "workflow_name": "sync_crm_to_airtable", "execution_id": {{$execution.id}}, "node_name": "Airtable Insert", "log_level": "INFO", "message": "New contact pushed to Airtable successfully", "metadata": { "recordId": "rec123", "fields": ["email", "firstName"] } }

• Repeat anywhere you need to log custom events.