Sync Notion to Todoist with n8n Webhooks + Redis Locks

Sync Notion database changes to Todoist tasks—safely, automatically, and loop-proof

This n8n workflow listens for Notion page events and keeps your corresponding Todoist tasks in sync—creating, updating, moving, completing/reopening, or deleting tasks as needed. It also uses Redis locks to prevent sync loops when changes bounce back and forth between systems.

What this workflow does

• Receives webhook events from Notion via a POST request from a Notion automation when a database page is created, updated, or deleted.
• Prevents processing loops with Redis locks by checking for a short-lived lock on the Notion page ID before continuing.
• Fetches the full Notion page through the Notion API and maps key properties (such as title, section, priority, due/recurrence, and status) into a Todoist task payload.
• Handles deletions and obsolescence: if the page is deleted, in the trash, or moved to an “Obsolete” section, the workflow deletes the matching Todoist task (when a Todoist task ID exists on the Notion page).
• Creates tasks on new pages: when a page is newly created, it creates a Todoist task and writes the returned Todoist task ID back to the Notion page.
• Updates tasks on property changes: retrieves the existing Todoist task, computes differences, updates fields, moves the task to the correct Todoist section, and closes or reopens it based on the Notion status.
• Sets short-lived locks for the relevant Notion/Todoist identifiers and ends the run cleanly.

Use cases

• Maintain a single source of truth in Notion while executing tasks in Todoist.
• Automatically mark Todoist tasks complete/reopen when the Notion status changes.
• Move work through Todoist sections based on Notion database fields (e.g., priority or workflow stage).
• Remove outdated items by deleting corresponding Todoist tasks when Notion pages are trashed or moved to “Obsolete”.

Technical details

• Integrations: Notion API, Todoist API
• Webhook-driven: HTTP POST receiver for Notion database page events
• Redis support: Redis locks to prevent sync loops
• n8n nodes used: if, set, code, no op, redis, filter
• Setup: Add notion_token and todoist_token in the Globals step (or use n8n credentials), and create Notion database properties that match the workflow’s field mapping (including a place to store the Todoist task ID).