Sync direction & field mapping
Configure how data flows between Notion and your connected apps
Sync direction controls how data flows between Notion and your connected apps. Field mapping determines which properties sync and in which direction. Together, they give you precise control over your automation.
What are the sync direction options?
Two-way sync (bidirectional)
Changes flow in both directions. Edit in Notion, and the external app updates. Edit in the external app, and Notion updates.
How it works:
- 2sync monitors both platforms for changes
- Updates detected in either location sync to the other
- Conflicts are resolved based on field-level sync direction settings
Best for:
- Calendar management where you edit events in both apps
- Task lists updated from mobile (Todoist, Microsoft To Do) and desktop (Notion)
- A Google Sheets tab your team keeps editing while you plan in Notion
- Any workflow requiring flexibility
Learn more about the differences in Two-way vs one-way sync.
One-way to Notion
Data flows from the external app to Notion only. Notion becomes a read-only archive or display layer.
Use cases:
- Email archival (Gmail/Outlook → Notion)
- Contact backup
- Calendar mirror for reference
- Logging completed items
Behavior:
- Changes in the external app update Notion
- Changes in Notion don't affect the external app
- Protects source data from accidental modification
One-way to external app
Data flows from Notion to the external app only. Notion becomes your "source of truth."
Use cases:
- Draft events in Notion, publish to calendar
- Plan tasks in Notion, sync to Todoist for mobile access
- Manage projects in Notion, display in external tools
Behavior:
- Changes in Notion update the external app
- Changes in the external app don't sync back
- Notion controls the data
How do I set sync direction?
At the automation level
Open your automation and go to the Fields tab. The Sync direction control at the top applies to every field below it:
- To [App] (for example, To Google Calendar): changes flow from Notion to the app only
- Both ways: edits on either side copy to the other
- To Notion: changes flow from the app to Notion only
Even with Both ways selected, a single field can still go one way only (see per-field direction below).
When you create an automation, the Connect step offers the same choice on a card that reads Both ways. Click Change on it to pick another direction before you continue.
Per-field direction
Even with a two-way automation, you can set individual fields to sync one direction only.
Example:
- Automation: 2-way sync between Google Calendar and Notion
- Event Name: Two-way (editable in both)
- Date: Two-way (editable in both)
- Organizer: One-way to Notion (read-only in Notion)
- Sync Status: One-way to Notion (informational)
To adjust per-field direction:
- Open the automation's Fields tab
- Find the field's row and click its direction button, between the app field and the Notion property
- Set the direction for that specific field
Blue two-way arrows mean the field syncs both ways. A gray single arrow means it syncs one way, in the direction the arrow points.
How does field mapping work?
Field mapping connects properties between your apps. Each mapping defines:
- Source field: The property in the external app
- Destination property: The property in Notion
- Direction: Which way changes sync
Adding fields
Not all fields are mapped by default. To add one:
- Open the automation's Fields tab
- Click + Add Field below the list
- Pick the app field and the Notion property it should fill
To change which Notion property an existing field fills, open the dropdown on its row. If a property you just created in Notion doesn't show up there, click Refresh Notion fields.
Removing fields
To stop syncing a field:
- Find its row on the Fields tab
- Click the trash icon at the end of the row
- That field stops syncing (existing data remains)
Required fields show a lock instead of a trash icon and can't be removed. In a Google Calendar automation, those are Event Name and Date.
Supported property types
Each external field is compatible with specific Notion property types:
| Field type | Compatible Notion properties |
|---|---|
| Text/Title | Title, Text, Select |
| Date/Time | Date |
| Boolean | Checkbox |
| Email, Text | |
| URL | URL, Text |
| List | Multi-select, Text |
| Enum | Select |
| Number | Number |
| Reference | Relation |
2sync only shows compatible properties when mapping.
How often does sync run?
The sync schedule depends on your plan:
| Plan | Interval | Description |
|---|---|---|
| Solo | 5 minutes | Changes sync every 5 minutes |
| Premium | 3 minutes | Faster updates |
| Pro | 2 minutes | Near real-time |
Immediate sync
Click Sync now on the automation's Status tab to trigger an immediate sync cycle. Useful after:
- Making bulk changes
- Setting up new mappings
- Testing configuration
How does conflict resolution work?
When the same item changes in both places between sync cycles, 2sync applies updates in both directions based on your field-level sync direction settings. Changes to different fields both apply. For the same field changed on both sides, the sync direction setting determines which update takes effect.
For a deeper look at conflict handling strategies, see Conflict resolution.
To avoid conflicts, try to edit items in one place at a time. If you frequently edit the same items in both apps, use per-field direction settings to control which side takes priority for each field.
How do I use formulas in field mapping?
You can map Notion formula properties for one-way syncing:
Setup:
- Set sync direction to one-way to the external app
- Map the formula property to a compatible field
Use case: Create a formula that combines first and last name, then map it to the event title.
Limitation: Formula outputs can only sync one direction (from Notion). The external app can't write to a formula.
Google Sheets reverses this for its own formulas: a formula column in the sheet syncs one way into Notion, and 2sync never writes into it. See Google Sheets fields.
Formula permission requirements
For formulas that reference relations or rollups:
- The related database must be connected to 2sync
- Without access, the formula returns empty
- Connect all referenced databases for formulas to work
Related
- How sync works for understanding the full sync lifecycle
- Two-way vs one-way sync for choosing the right direction
- Conflict resolution for handling simultaneous edits
- Advanced sync settings for fine-tuning your automation
- Glossary for definitions of sync terminology
FAQ
Can I sync individual fields one-way in a two-way automation?
Yes. Set the automation to Both ways on the Fields tab, then click the direction button on each field's row. Some fields can sync both ways while others sync one direction.
What happens if I change sync direction on an existing automation?
Existing synced items retain their links. The new direction applies to future changes. No data is deleted by changing direction.
Why is my formula showing empty?
Formulas that reference relations or rollups need all related databases connected to 2sync. Without access, 2sync can't read the formula output.
Can I map the same external field to multiple Notion properties?
Not directly. Each external field maps to one Notion property. Use Notion formulas to derive additional properties from synced data.
What if I remove a field mapping?
The field stops syncing. Existing data in both apps remains. The link between those fields is broken for future changes.