Automated Excel Row to Xero Invoice Sync (n8n)

1. **Establish Credentials**: In n8n, go to 'Credentials' and create 'Microsoft Online' (OAuth2) and 'Xero' (OAuth2) connections. Ensure your Xero app has `acc.transactions` and `contact.read` scopes. 2. **Setup Excel Trigger**: Add the 'Microsoft Excel Online Trigger' node. Set the 'Resource' to 'Row' and 'Event' to 'Created'. Select your Spreadsheet and the specific **Table** name (not just the sheet name). 3. **Search for Contact**: Add a 'Xero' node. Action: 'Get Many' for 'Contact'. Use a filter expression: `{{ $json["Customer Name"] }}` to check if the customer already exists in Xero. 4. **Conditional Logic (IF Node)**: Insert an 'IF' node after the Search. If the Xero search returns an empty array, route to a Xero 'Create Contact' node; otherwise, proceed to invoice creation. 5. **Format Dates with Expressions**: n8n expressions are needed for date compatibility. Use `{{ $today.format('yyyy-MM-dd') }}` for the Invoice Date and `{{ $json["Due Date"].toDate().toISOString() }}` to ensure Xero accepts the Excel date format. 6. **Map Invoice Line Items**: Add a 'Xero' node with Resource: 'Invoice' and Action: 'Create'. Set 'Status' to 'DRAFT'. Map the 'Line Items' using an n8n expression to build the JSON array containing Description, Quantity, and UnitAmount. 7. **Include Account Codes**: Map the 'AccountCode' field. In n8n, use a fixed value like `200` (Sales) or a mapping expression if the code exists in your Excel column. 8. **Implement Error Handling**: Create an 'Error Trigger' workflow or use the 'On Error' setting on the Xero node to 'Route to another node' (e.g., Slack or Email) if the API returns a 400 error due to invalid account codes or missing data.