Gmail to freee Invoice Drafts (Claude Haiku) n8n Automation

Turn Gmail orders into freee Invoice drafts automatically—using Claude Haiku

This n8n automation watches for new customer orders in Gmail (or a public n8n form), matches them to your freee quotations, then uses Anthropic Claude (Haiku) to interpret the order and create an UNSENT Invoice draft in freee—finally notifying staff by Gmail.

What this workflow does

• Triggers on a new Gmail message matching a subject search query or when someone submits the “order-to-freee-invoice” n8n form.
• Extracts order details (sender email, subject, and plain-text message) and applies shared settings like company ID, payment terms, and the staff notification email.
• Identifies the customer in freee by matching the sender email or a unique partner name found in the order text.
• Finds the right quotation by retrieving the customer’s open freee quotations (prioritizing any mentioned Q-… number) and loading the top candidates’ details.
• Interprets the order with Claude Haiku by sending the order text and quotation line summaries to determine whether it’s a clear order, which quotation it references, and any requested quantity changes or additions.
• Validates and prevents duplicates in code, checks whether an existing invoice already references the quotation number, applies only verifiable quantity changes, and converts unclear additions into “To check” note lines.
• Creates an UNSENT freee Invoice draft using pricing/taxes from the selected quotation and sends staff a detailed result via Gmail.

Use cases

• Sales receives email orders with quantity tweaks; you want draft invoices created in freee without manual re-entry.
• Orders mention a specific quotation number (Q-…); the workflow selects that quotation and updates quantities automatically.
• When the request is ambiguous, staff still get a clear “To check” invoice draft for review.

Technical details

• Integrations/nodes: Gmail, form, if, set, switch, code
• AI: Anthropic Claude (Haiku) for order interpretation
• freee API: partner lookup, open quotation retrieval, and invoice draft creation (UNSENT)
• Includes: duplicate prevention by checking existing invoices referencing quotation numbers