How to Automate Invoice Parsing in n8n

n8n is a workflow automation tool that connects apps and APIs without writing code. This guide shows how to build a workflow that takes an invoice file and automatically extracts the structured data using DocuParseAPI.

What We're Building

A workflow that:

1. Triggers when a new invoice arrives (email attachment, Google Drive, or manual trigger)
2. Calls DocuParseAPI to extract the invoice data
3. Writes the extracted fields to Google Sheets (or any other destination)

Total setup time: 15–20 minutes.

What You Need

• n8n (cloud or self-hosted)
• A DocuParseAPI account — free at docuparseapi.com/signup
• A Google account (for Google Sheets output — or substitute any other destination node)

Step 1: Get Your API Key

1. Sign up at docuparseapi.com/signup
2. Go to Dashboard → API Keys
3. Create a new key and copy it immediately (shown only once)

Step 2: Create the Workflow

Node 1: Trigger

For testing, use the Manual Trigger node. For production, replace with:

• Email Trigger (IMAP): fires when a new email arrives with an attachment
• Google Drive Trigger: fires when a new file appears in a folder
• Webhook: fires when your app posts an invoice file

Node 2: HTTP Request (DocuParseAPI call)

Add an HTTP Request node with these settings:

Method: POST
URL: https://docuparseapi.com/api/v1/extract
Authentication: Header Auth
  Header Name: Authorization
  Header Value: Bearer YOUR_API_KEY_HERE
Body Content Type: Form-Data/Multipart
Body Parameters:
  Name: file
  Value: [binary data from previous node]
  Type: File

If your previous node outputs a file (e.g., an email attachment), set the file value to the binary output of that node using the expression: {{ $binary.data }}.

Node 3: Parse the Response

Add a Set node to extract the fields you need:

merchant: {{ $json.merchant }}
total: {{ $json.total }}
tax: {{ $json.tax }}
currency: {{ $json.currency }}
date: {{ $json.date }}
due_date: {{ $json.due_date }}
invoice_id: {{ $json.invoice_id }}

Node 4: Write to Google Sheets

Add a Google Sheets node:

• Operation: Append
• Sheet: your invoice tracking sheet
• Map the fields from the Set node to your sheet columns

The Complete Workflow (JSON Import)

You can import this directly into n8n:

Handling Errors in n8n

Add an IF node after the HTTP Request to check for success:

• Condition: {{ $json.success }} equals true
• True branch: continue to Extract Fields
• False branch: send a notification (Slack, email) with {{ $json.error.code }}

Common errors and what they mean:

• LIMIT_EXCEEDED — you've hit your monthly document limit; upgrade your plan
• EXTRACTION_FAILED — the document couldn't be parsed; check the file quality
• UNSUPPORTED_FILE_TYPE — only PDF, JPG, PNG are supported

Real Workflow: Email Invoice → Google Sheet

This is the most common use case for small businesses:

1. Email Trigger (IMAP): Watch an email inbox for supplier invoices
2. Filter: Check if the email has a PDF attachment
3. HTTP Request: Send the attachment to DocuParseAPI
4. IF: Check success === true
5. Google Sheets: Append a new row with extracted fields
6. Slack/Email: Send a notification that the invoice was processed

With this workflow, every supplier invoice that arrives in your inbox is automatically extracted and logged to a spreadsheet — no manual data entry.

Next Steps

• API documentation — authentication, response format
• Invoice parsing Python tutorial
• Make.com invoice parsing guide
• Try DocuParseAPI free