n8n

Prerequisites

• A PolyDoc account and API key — sign up for free, no credit card required. The free plan includes 150 PDF conversions per month.
• An n8n instance — self-host for free or use n8n Cloud.

Use Case 1: Generate PDFs from Spreadsheet Data

Automatically generate an invoice PDF for every new row added to a Google Sheet and email it to the recipient.
Google Sheets trigger (new row) → HTTP Request (PolyDoc API) → Gmail

n8n expressions use {{ $json.fieldName }} syntax — map your spreadsheet columns directly into the PolyDoc request body.

Create a new workflow

Open your n8n instance and click Add workflow. Give it a descriptive name like "Invoices → PDF → Email".

Screenshot placeholder: /img/guides/n8n/n8n-uc1-create-workflow.png

Add a Google Sheets trigger node

Add a worksheet with column headers that match your PolyDoc template. The example below uses an invoices tab and one sample row; you can import data via File → Import (CSV/XLSX).

invoice_number	invoice_date	invoice_due_date	invoice_subtotal	invoice_tax_rate	invoice_tax_amount	invoice_total	customer_name	customer_email	customer_street	customer_city	customer_country
INV-2026-001	2026-01-15	2026-02-14	1200	0.1	120	1320	John Doe	john.doe@example.com	456 Customer Avenue	Beautiful City	UK

Click Add first step and select Google Sheets → On Row Added. Connect your Google account, choose your spreadsheet, and select the invoices tab.

n8n will poll for new rows at the interval you configure (default: every minute). Click Fetch Test Event to pull in a sample row.

Screenshot placeholder: /img/guides/n8n/n8n-uc1-sheets-trigger.png

Add an HTTP Request node for PolyDoc

Add an HTTP Request node after the trigger and configure:

• Method: POST
• URL: https://api.polydoc.tech/pdf/convert
• Authentication: Generic Credential Type → Header Auth
• Create a credential with Name Authorization and Value Bearer YOUR_API_KEY (get your key from the Dashboard)
• Add header: X-Sandbox = true
• Body Content Type: JSON
• Specify Body: use JSON and map row fields with expressions like {{ $json.customer_name }}
• Options → Response: set Response Format to File so the PDF binary is available for the next node

Screenshot placeholder: /img/guides/n8n/n8n-uc1-http-request.png

Send the PDF by email

Add a Gmail node (or any email node) after the HTTP Request. Configure:

• To: {{ $('Google Sheets Trigger').item.json.customer_email }}
• Subject: Your PDF — {{ $('Google Sheets Trigger').item.json.invoice_number }}
• Attachments: select the binary data from the HTTP Request node

Screenshot placeholder: /img/guides/n8n/n8n-uc1-gmail-node.png

Execute and activate the workflow

Click Test workflow to run it once with a sample row. Verify the PDF arrives in the recipient's inbox. When satisfied, toggle the workflow to Active so it runs automatically on new rows.

Screenshot placeholder: /img/guides/n8n/n8n-uc1-activate.png

Use Case 2: Webhook-Triggered PDF

Accept incoming JSON via a webhook, generate a PDF with PolyDoc, and return it directly in the HTTP response.
Webhook node → HTTP Request (PolyDoc API) → Respond to Webhook

Add a Webhook node

Create a new workflow. Add a Webhook node as the trigger. Set the HTTP Method to POST. Copy the Test URL shown in the node — you'll use it in the next step.

Screenshot placeholder: /img/guides/n8n/n8n-uc2-webhook-node.png

Send test data to the webhook

Send a test POST request with JSON data to the webhook URL. For example using curl:

curl -X POST <YOUR_TEST_URL> \
  -H "Content-Type: application/json" \
  -d '{"name": "Jane Doe", "amount": "€1,200.00"}'

n8n will capture the payload and display the received fields in the Webhook node output.

Screenshot placeholder: /img/guides/n8n/n8n-uc2-test-webhook.png

Add an HTTP Request node for PolyDoc

Add an HTTP Request node and configure it the same way as in Use Case 1:

• URL: https://api.polydoc.tech/pdf/convert
• Method: POST
• Header Auth credential: Authorization = Bearer YOUR_API_KEY
• Header: X-Sandbox = true
• JSON body: map webhook fields using {{ $json.name }}, {{ $json.amount }}, etc.
• Response Format: File

Screenshot placeholder: /img/guides/n8n/n8n-uc2-http-request.png

Return the PDF in the response

Add a Respond to Webhook node. Set Respond With to Binary and select the PDF data from the previous node. This returns the generated PDF directly to the caller.

Alternatively, you can respond with a JSON body containing a download link if you store the PDF in cloud storage first.

Screenshot placeholder: /img/guides/n8n/n8n-uc2-respond-webhook.png

Activate the workflow

Click Test workflow and send another POST to the test URL. Confirm the PDF is returned. Then toggle the workflow to Active — the Production URL (different from the test URL) will be live and ready to accept requests.

Screenshot placeholder: /img/guides/n8n/n8n-uc2-activate.png