This article provides a complete, practical walkthrough of the Webhook Code Create Webhook n8n agent. It connects HTTP Request, Webhook across approximately 1 node(s). Expect a Intermediate setup in 15-45 minutes. One‑time purchase: €29.

What This Agent Does

This agent orchestrates a reliable automation between HTTP Request, Webhook, handling triggers, data enrichment, and delivery with guardrails for errors and rate limits.

It streamlines multi‑step processes that would otherwise require manual exports, spreadsheet cleanup, and repeated API requests. By centralizing logic in n8n, it reduces context switching, lowers error rates, and ensures consistent results across teams.

Typical outcomes include faster lead handoffs, automated notifications, accurate data synchronization, and better visibility via execution logs and optional Slack/Email alerts.

How It Works

The workflow uses standard n8n building blocks like Webhook or Schedule triggers, HTTP Request for API calls, and control nodes (IF, Merge, Set) to validate inputs, branch on conditions, and format outputs. Retries and timeouts improve resilience, while credentials keep secrets safe.

Third‑Party Integrations

• HTTP Request
• Webhook

Import and Use in n8n

1. Open n8n and create a new workflow or collection.
2. Choose Import from File or Paste JSON.
3. Paste the JSON below, then click Import.
4. Show n8n JSON

   **Title:**
   Automating PDF Invoice Classification and Cloud Storage with n8n and OpenAI
   
   **Meta Description:**
   Discover how an advanced n8n workflow uses OpenAI and Google Drive to automatically classify PDF invoices from Gmail and upload them to a designated folder—with optional email summaries for your accountant.
   
   **Keywords:**
   n8n automation, OpenAI GPT-4, Gmail attachment parsing, invoice classification, Google Drive integration, PDF receipt filtering, AI document categorization, automated email workflows, OpenAI document processing, GPT invoice tagger, n8n tutorial
   
   ---
   
   **Automating Invoice & Receipt Classification with OpenAI and n8n**
   
   Managing PDF invoices and receipts manually from email can be a tedious process, especially when you’re trying to stay organized for tax season or monthly accounting. What if your system could intelligently scan your Gmail inbox, extract relevant PDFs, apply natural language reasoning to filter business-related expenses, and automatically upload everything to a structured Google Drive folder?
   
   Using the open-source workflow automation platform n8n, paired with OpenAI’s powerful GPT-4 language model, this is not only possible—it’s fully automated.
   
   Let’s break down how this robust workflow operates and how it leverages artificial intelligence and cloud services to streamline document classification.
   
   ---
   
   ### The Problem It Solves
   
   Imagine you're a freelancer, startup founder, or anyone actively managing business expenses. You frequently receive receipts, invoices, and other business documents in PDF format via email. But separating valid business receipts from personal ones (or outright spam), organizing them by date, and sending them to the right stakeholders (like your accountant) can add up to hours of repetitive, error-prone work.
   
   This workflow solves that by:
   - Scanning your Gmail inbox over a chosen date range,
   - Filtering for PDF attachments only,
   - Using natural language AI reasoning to determine which PDFs qualify as business-related invoices or receipts,
   - Uploading matched files to a Google Drive folder named by date,
   - Optionally emailing these documents directly to your accountant.
   
   ---
   
   ### How It Works — Step-by-Step
   
   1. **Trigger via Webhook**
      A custom webhook serves as the starting point. You call it with two mandatory parameters (`startDate` and `endDate`) and an optional flag `sendEmail=true` to indicate if documents should be emailed at the end.
   
   2. **Create a Google Drive Folder**
      A new folder is created in your Google Drive, named something like `invoices_2024-01-01`. This gives a central location for matched PDF uploads.
   
   3. **Fetch Gmail Emails**
      The workflow pulls emails from Gmail within the specified date range that contain PDF attachments. An optional filter ensures only valid recipients are processed.
   
   4. **Iterate Over Attachments & Filter PDFs**
      Through a loop and conditional branches, the system ensures only attachments with a `.pdf` extension are passed forward.
   
   5. **Extract PDF Text and Apply OpenAI Classification**
      Using n8n’s PDF reader node, the text content of the PDF is extracted. If the content is within the defined token limits (default allows content <= 8000 tokens), it is passed to an OpenAI "Chat" node.
   
      The message sent to OpenAI prompts it to evaluate whether the PDF contains a "receipt or invoice that can be considered a software engineering business cost." It returns a simple boolean `true` or `false`.
   
   6. **Conditional Upload to Google Drive**
      If OpenAI returns `true`, the original binary PDF file is uploaded to the newly created Google Drive folder.
   
   7. **Aggregate and Send Email (Optional)**
      If the `sendEmail` flag was set to `true` in the webhook request, all matched PDFs are aggregated and attached to an email. A prewritten message and subject line are generated, and the documents are sent to the email specified in the configuration.
   
   ---
   
   ### Customization Features
   
   - **Match Constraint**: You can change what documents the system searches for by editing the `"Match on"` value in the configuration node. For example, search PDFs for the phrase "contract" instead of "receipt or invoice."
     
   - **Email Toggle**: The email sending is entirely optional and controlled via the webhook input, making this ideal for both silent batch processing and active notifications.
   
   - **Token Limits**: To safeguard against API failures or excessive costs, the workflow checks the number of tokens in each PDF and only processes those under a defined limit (default: 8000). This allows for careful control over context sent to OpenAI.
   
   ---
   
   ### Third-Party APIs Used
   
   This workflow uses the following external services:
   
   1. **OpenAI API**
      - Purpose: Evaluates the PDF text content to see if it aligns with the classification (e.g., "business receipt or invoice").
      - Model used: GPT-4.1-mini via Chat endpoint.
   
   2. **Google Gmail API**
      - Purpose: Fetches emails with attachments and handles outbound sending of the final email with matched PDFs.
   
   3. **Google Drive API**
      - Purpose: Creates a new folder and uploads matched PDF attachments for archiving or sharing.
   
   ---
   
   ### Why This Approach Is Powerful
   
   Combining OpenAI's comprehension abilities with n8n’s low-code automation platform brings intelligent classification into your daily workflow. Rather than relying on file names or static rules to guess the document type, you’re getting contextual understanding from a state-of-the-art language model.
   
   This makes your automated filter far better at handling edge cases, varying invoice formats, and spotting business-related terminology embedded within receipts.
   
   ---
   
   ### Final Thoughts
   
   This workflow liberates you from the mundane task of sorting through invoices and receipts—while boosting accuracy, traceability, and storage hygiene. Whether you're preparing for end-of-month reporting or simply want to declutter your inbox, the combination of n8n, OpenAI, and Google’s services provides a plug-and-play solution that saves time and empowers smart automation.
   
   To explore and deploy this workflow yourself, make sure you’re using n8n with authenticated access to OpenAI, Gmail, and Google Drive—and always double-check results before trusting AI judgment blindly.
   
   ---
   
   Workflow created by [Tom at BrowseWiz.com](https://browsewiz.com) 💼✨

5. Set credentials for each API node (keys, OAuth) in Credentials.
6. Run a test via Execute Workflow. Inspect Run Data, then adjust parameters.
7. Enable the workflow to run on schedule, webhook, or triggers as configured.

Tips: keep secrets in credentials, add retries and timeouts on HTTP nodes, implement error notifications, and paginate large API fetches.

Validation: use IF/Code nodes to sanitize inputs and guard against empty payloads.

Why Automate This with AI Agents

AI‑assisted automations offload repetitive, error‑prone tasks to a predictable workflow. Instead of manual copy‑paste and ad‑hoc scripts, your team gets a governed pipeline with versioned state, auditability, and observable runs.

n8n’s node graph makes data flow transparent while AI‑powered enrichment (classification, extraction, summarization) boosts throughput and consistency. Teams reclaim time, reduce operational costs, and standardize best practices without sacrificing flexibility.

Compared to one‑off integrations, an AI agent is easier to extend: swap APIs, add filters, or bolt on notifications without rewriting everything. You get reliability, control, and a faster path from idea to production.

Best Practices

• Credentials: restrict scopes and rotate tokens regularly.
• Resilience: configure retries, timeouts, and backoff for API nodes.
• Data Quality: validate inputs; normalize fields early to reduce downstream branching.
• Performance: batch records and paginate for large datasets.
• Observability: add failure alerts (Email/Slack) and persistent logs for auditing.
• Security: avoid sensitive data in logs; use environment variables and n8n credentials.

FAQs

Can I swap integrations later? Yes. Replace or add nodes and re‑map fields without rebuilding the whole flow.

How do I monitor failures? Use Execution logs and add notifications on the Error Trigger path.

Does it scale? Use queues, batching, and sub‑workflows to split responsibilities and control load.

Is my data safe? Keep secrets in Credentials, restrict token scopes, and review access logs.