Description
Overview
This PDF attachment filtering automation workflow efficiently identifies and processes specific PDF files based on their textual content. Designed as a no-code integration pipeline, it targets users who need to automatically sort and store relevant PDF documents, such as payslips or invoices, by leveraging content-based filtering triggered by incoming Gmail emails.
The workflow initiates with an email-received trigger that downloads attachments, then uses OpenAI to verify if the content matches a predefined search term, enabling selective upload to Google Drive.
Key Benefits
- Automates extraction and filtering of PDF attachments from Gmail emails in real time.
- Applies content-based filtering using OpenAI to identify relevant documents by keyword.
- Supports no-code integration with configurable parameters for search term and storage location.
- Ensures only PDFs within token limits are processed, avoiding oversized file errors.
- Uploads matched PDF files directly to a specified Google Drive folder for centralized storage.
Product Overview
This automation workflow is triggered by incoming emails in Gmail, specifically set to retrieve and process all email attachments. It first verifies whether attachments exist before proceeding. Each attachment is individually extracted and checked for the PDF file extension. If confirmed as a PDF, the workflow reads its textual content using a dedicated PDF reader node.
Text length is evaluated against configured token limits to ensure compatibility with OpenAI’s processing capacity. PDFs exceeding this limit are bypassed. For those within limits, the extracted text and filename are sent to the OpenAI node, which uses a prompt to determine if the content matches a user-defined keyword (e.g., “payslip”). OpenAI returns a binary true/false response indicating relevance.
Matched PDFs are then uploaded directly to a Google Drive folder designated by the user through a configurable URL. The workflow handles processing synchronously per email and attachment, with default error handling provided by the n8n platform. Authentication uses OAuth2 credentials for Gmail and Google Drive, and API key-based access for OpenAI.
Features and Outcomes
Core Automation
This event-driven analysis pipeline processes email attachments, applying content-based filtering using OpenAI. It evaluates PDFs one at a time, with decision branches for file type, token size limits, and content matching.
- Single-pass evaluation of each attachment for PDF type and textual content.
- Deterministic routing based on OpenAI’s binary true/false output for matching.
- Selective forwarding of matched PDFs to storage, minimizing manual intervention.
Integrations and Intake
The orchestration pipeline integrates Gmail for inbound email capture, OpenAI for content analysis, and Google Drive for storage. OAuth2 secures Gmail and Drive access, while OpenAI credentials enable token-limited content querying.
- Gmail trigger node monitors email inbox and downloads attachments automatically.
- OpenAI node applies natural language understanding to PDF text for keyword matching.
- Google Drive node uploads matched PDFs to a user-specified folder by folder ID.
Outputs and Consumption
The workflow outputs matched PDF files asynchronously to Google Drive, preserving original filenames. Non-matching or unsupported files are ignored without further processing.
- PDF files uploaded as binary data to Google Drive folder identified by URL.
- OpenAI returns simple “true” or “false” textual responses for content relevance.
- Unmatched or oversized PDFs do not produce output, preventing unnecessary uploads.
Workflow — End-to-End Execution
Step 1: Trigger
The workflow activates upon receiving an email in Gmail, using the Gmail Trigger node configured to download all attachments. This polling occurs every minute, ensuring near real-time processing of incoming emails.
Step 2: Processing
Attachments are extracted individually via a code node that iterates over all binary attachments in the email. Each attachment is then filtered through an “Is PDF” node that checks the file extension. Non-PDF files are bypassed, while PDFs proceed to content extraction.
Step 3: Analysis
PDF text content is extracted using the Read PDF node. A subsequent conditional node verifies that the text length falls within a configured token limit, calculated to ensure OpenAI prompt compatibility. If compliant, the text and filename are sent to OpenAI, which returns a strict “true” or “false” indicating whether the content matches the configured keyword (e.g., “payslip”).
Step 4: Delivery
Attachments confirmed as matches are uploaded via the Google Drive node to a user-defined folder extracted from a URL. Uploads preserve the original filename. PDFs that do not match or exceed token limits are excluded from this final step.
Use Cases
Scenario 1
An HR department receives numerous emails with various attachments and needs to archive employee payslips automatically. This workflow filters incoming attachments, identifies payslips by content, and uploads only relevant PDFs to a secure Google Drive folder, eliminating manual sorting.
Scenario 2
A finance team wants to collect invoices sent via email without manually reviewing each document. By configuring the workflow’s keyword to “invoice,” the system detects and uploads only invoice PDFs from email attachments, ensuring streamlined document management with deterministic filtering.
Scenario 3
Legal teams managing contracts need to capture and store signed PDFs from various email senders. Using this automation pipeline with “contract” as the search term, the workflow extracts and uploads matching PDFs, reducing processing time and supporting consistent document collection.
How to use
To implement this PDF attachment filtering automation workflow within n8n, import the workflow JSON and configure the key parameters in the “Configure” node. Set the search term (“Match on”) to the desired keyword, such as “payslip” or “invoice,” and specify the Google Drive folder URL for matched file uploads.
Ensure OAuth2 credentials for Gmail and Google Drive and API key credentials for OpenAI are properly set up. Activate the workflow to start monitoring the Gmail inbox. Incoming emails with attachments will be scanned automatically, and matched PDFs will be uploaded to the configured drive folder. Results include selective document storage without manual intervention.
Comparison — Manual Process vs. Automation Workflow
| Attribute | Manual/Alternative | This Workflow |
|---|---|---|
| Steps required | Multiple manual stages: email review, attachment download, file reading, sorting, and uploading. | Automated end-to-end processing from email receipt to Google Drive upload without manual steps. |
| Consistency | Subject to human error, inconsistent keyword matching and file handling. | Deterministic keyword-based filtering using OpenAI ensures uniform identification of relevant PDFs. |
| Scalability | Limited by manual capacity and time constraints. | Scales with email volume, processing attachments asynchronously per email automatically. |
| Maintenance | Requires ongoing manual effort and training for document sorting. | Minimal maintenance after configuration; relies on credential validity and API availability. |
Technical Specifications
| Environment | n8n workflow execution environment with Gmail, OpenAI, and Google Drive integration. |
|---|---|
| Tools / APIs | Gmail API (OAuth2), OpenAI API (API key), Google Drive API (OAuth2). |
| Execution Model | Event-driven, triggered on new email receipt with synchronous per-attachment processing. |
| Input Formats | Emails with binary PDF attachments downloaded from Gmail. |
| Output Formats | Binary PDF files uploaded to Google Drive folder preserving original filenames. |
| Data Handling | Transient processing of PDF text content; no persistent storage within workflow. |
| Known Constraints | PDF text must be within token limits defined by maxTokenSize and replyTokenSize to be processed by OpenAI. |
| Credentials | OAuth2 for Gmail and Google Drive; API key authentication for OpenAI node. |
Implementation Requirements
- Active Gmail account with OAuth2 credentials configured in n8n for email monitoring and attachment access.
- OpenAI API key with access to appropriate language model for content analysis and filtering.
- Google Drive account with OAuth2 credentials and access to the target folder for PDF uploads.
Configuration & Validation
- Set the “Match on” keyword in the Configure node to define which PDF content to filter.
- Verify OAuth2 credentials for Gmail and Google Drive are authorized and active in n8n.
- Test workflow with sample emails containing PDF attachments to confirm correct filtering and uploading behavior.
Data Provenance
- Trigger node: “On email received” monitors Gmail inbox for new emails with attachments.
- Content filtering: “OpenAI matches PDF textual content” node uses OpenAI API with prompt-driven keyword detection.
- File delivery: “Upload file to folder” node uploads matched PDFs to Google Drive folder ID derived from Configure node URL.
FAQ
How is the PDF attachment filtering automation workflow triggered?
The workflow triggers automatically on each new email received in Gmail, downloading all attachments for processing.
Which tools or models does the orchestration pipeline use?
It integrates Gmail for email intake, OpenAI for textual content filtering using a keyword search prompt, and Google Drive for final file storage.
What does the response look like for client consumption?
Matched PDFs are uploaded to the specified Google Drive folder preserving original filenames; OpenAI returns “true” or “false” indicating content relevance.
Is any data persisted by the workflow?
PDF text content is processed transiently in memory; the workflow does not persist or store any data besides uploading matched PDFs to Google Drive.
How are errors handled in this integration flow?
The workflow relies on n8n’s default error handling; attachments exceeding token limits are ignored to prevent processing failures.
Conclusion
This PDF attachment filtering automation workflow provides a structured method to identify and store specific PDF documents from incoming Gmail emails based on textual content. It delivers consistent, deterministic outcomes by combining event-driven email triggers, OpenAI keyword-based content analysis, and targeted Google Drive uploads. The workflow requires valid OAuth2 credentials and API access and operates within token size constraints imposed by OpenAI, ensuring reliable processing without manual intervention. This setup supports scalable and maintainable document management aligned with enterprise content handling requirements.
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