n8n Workflow: Create QuickBooks Invoices from Won HubSpot Deals

Create QuickBooks invoices automatically from Won HubSpot deals (with Slack alerts)

This n8n workflow finds Won HubSpot deals missing a quickbooks_invoice_number, then creates the matching customer and invoice in QuickBooks Online—and sends Slack alerts whenever a contact email is missing, an invoice needs review, or any step fails.

What this workflow does

• Runs hourly on a schedule.
• Searches HubSpot for deals in your configured won stage that do not have quickbooks_invoice_number, are closed on/after a configured start date, and have an amount greater than zero.
• Loads deal context by fetching the associated contact and HubSpot line item IDs, then retrieves primary contact details.
• Validates contact email:
  • If the contact has no email, the workflow updates the HubSpot deal to MISSING-CONTACT and posts a Slack** message asking sales to add a contact email.
  • If an email exists, it proceeds with invoice creation.
• Builds invoices from HubSpot line items, finds (or creates) the matching QuickBooks Online customer by email, and creates the invoice in QuickBooks Online.
• Prevents double billing by writing the generated QuickBooks invoice number back to HubSpot as quickbooks_invoice_number.
• Route invoice delivery:
  • When enabled (and within the configured amount limit), it emails the invoice via QuickBooks.
  • Otherwise, it posts a Slack message for finance to review and send.
• Failure visibility: on any invoice-processing error, it posts a Slack alert with the deal, failing step, and error details.

Use cases

• Reduce manual work by converting newly won HubSpot deals into QuickBooks Online invoices automatically.
• Catch data issues early by flagging missing contact emails directly in Slack and marking HubSpot deals as MISSING-CONTACT.
• Ensure finance review for higher-value invoices or cases where automated emailing is disabled.

Technical details

• Integrations: HubSpot (private app token), QuickBooks Online, Slack
• n8n nodes / logic: if, set, code, slack, filter, hubspot
• Core behavior: hourly schedule, deal filtering, customer lookup/creation by email, invoice creation, HubSpot field update to avoid duplicates, and Slack alerts on both business exceptions and technical failures.