🔬 Generate branded PDF sales proposals with Gemini, APITemplate.io and Gmail
⚡ 0 views · 🔬 Document Extraction & Analysis
Description
Quick overview
This workflow collects prospect details via an n8n form, uses Google Gemini to draft a structured sales proposal, renders it into a branded PDF using APITemplate.io, and creates a pre-addressed Gmail draft with the PDF attached (or emails you an error if PDF rendering fails).
How it works
- Receives a submission from an n8n form containing the prospect’s company details, situation, proposed services, pricing, timeline, and optional brand colors.
- Sends the submission to Google Gemini to generate proposal content as structured JSON that matches a predefined schema.
- Validates the generated sections and item counts, applies fallback brand colors when needed, and merges the content into a fixed-layout HTML proposal template.
- Calls the APITemplate.io API to convert the HTML into an A4 PDF file.
- Creates a Gmail draft addressed to the prospect with the PDF attached and a prewritten message that references the generated proposal highlights.
- If PDF generation fails, sends an error email to the agency address so you can troubleshoot and rerun.
Setup
- Add a Google Gemini credential and ensure the selected model is available in your account.
- Add an APITemplate.io API key as an HTTP Header Auth credential using the header name
X-API-KEY. - Add a Gmail OAuth credential with permission to create drafts, and confirm the workflow uses the prospect email from the form as the recipient.
- Edit the CONFIG block in the HTML-building code to set your agency name, email, phone number, timezone, and default brand colors.
- Activate the workflow and share the n8n form URL with whoever submits proposal requests.
Requirements
- A Google Gemini API key, or any other chat model you prefer.
- A Gmail account. The draft appears in that account’s Drafts folder.
- An APITemplate.io account. The free tier is enough to try it.
Customization
- Swap the Google Gemini sub-node for OpenAI, Anthropic or any other chat model. The output parser keeps the rest of the workflow unchanged.
- Edit the HTML template inside Build HTML to change the design, fonts or section order.
- Change the form fields, and the matching lines in the prompt, to collect different information.
- Adjust the length limits in the system prompt if your layout needs longer or shorter text.
Additional info
The prompt forbids inventing numbers: every price, percentage and date in the PDF comes from what you typed in the form. And nothing is emailed automatically — the workflow leaves a Gmail draft so you review it before sending.
🔗 Nodes Used
HTTP Request, Gmail, Basic LLM Chain, Structured Output Parser, n8n Form Trigger, Google Gemini Chat Model
📥 Import
Download workflow.json and import into n8n:
Workflow menu → Import from File