n8n Workflow: Gemini Sales Proposal PDF + Gmail Draft

Turn form submissions into a branded sales proposal PDF—then draft the Gmail for you

This n8n workflow collects prospect details from an n8n form, uses Google Gemini to generate structured sales proposal content, renders it into a branded A4 PDF via APITemplate.io, and creates a pre-addressed Gmail draft with the PDF attached. If PDF rendering fails, it automatically emails you an error so you can troubleshoot and rerun.

What this workflow does

• Receives a form submission containing company details, situation, proposed services, pricing, timeline, and optional brand colors.
• Generates proposal content with Google Gemini as structured JSON that matches a predefined schema.
• Validates and finalizes the proposal (including fallback brand colors when needed) and merges the content into a fixed-layout HTML proposal template.
• Renders the HTML into a branded A4 PDF using the APITemplate.io API.
• Creates a Gmail draft addressed to the prospect with a prewritten message and the PDF attached.
• Error handling: if PDF generation fails, it emails the agency address so you can quickly diagnose the issue and rerun.

Use cases

• Agencies or SaaS teams that want instant proposal generation from inbound lead forms.
• Sales operations teams needing consistent, schema-based proposals without manual formatting.
• Teams sending proposals by email while ensuring every message includes the latest Gemini-generated PDF.

Technical details

• Google Gemini integration to produce structured proposal JSON (schema-aligned).
• APITemplate.io to convert the finalized HTML proposal into an A4 PDF (API key provided via HTTP header X-API-KEY).
• Gmail OAuth to create drafts, using the prospect email from the form as the recipient.
• n8n nodes include Code, Gmail, Form Trigger, HTTP Request, and LLM-related components.

Build smarter sales automation with n8n—from lead intake to proposal PDF and a ready-to-send Gmail draft.