Step 1: Trigger for Document Ingestion. Configure a trigger node (e.g., 'Google Drive Trigger', 'S3 Trigger', 'Webhook') to initiate the workflow when a new document (image or PDF) is uploaded to a specified location or received.
Step 2: Download Document. Use an appropriate node (e.g., 'Google Drive', 'S3', 'HTTP Request') to download the document file into the n8n workflow for processing.
Step 3: Perform OCR. Integrate an OCR service node (e.g., 'Google Vision AI', 'Azure Cognitive Services', 'Amazon Textract' or a custom HTTP Request node to a self-hosted Tesseract API). Configure the node to extract all text from the uploaded document. The output will be raw, unstructured text.
Step 4: Extract Structured Data with LLM. Pass the raw text output from the OCR node to an 'LLM Chat' or 'LLM Predict' node (e.g., OpenAI, Gemini). Craft a precise prompt instructing the LLM to extract specific fields (e.g., 'invoice number', 'vendor name', 'total amount', 'line items with descriptions and prices') into a JSON object format. Emphasize clarity and examples in your prompt (few-shot prompting).
Step 5: Validate and Transform Data. Use a 'Set' node or 'Code' node to validate the extracted data types (e.g., ensure 'total amount' is a number) and transform it into the desired structure for your downstream system. Implement conditional logic ('If' node) to handle missing or incorrectly extracted fields.
Step 6: Store or Route Data. Connect to a database ('Postgres', 'MySQL', 'MongoDB'), CRM ('Salesforce', 'HubSpot'), or other application node to store the newly structured data. For example, use a 'Postgres' node to insert the extracted invoice details into an invoices table.
Step 7: Notification and Error Handling. Add a 'Send Email' or 'Slack' node to send notifications upon successful processing or to alert administrators if errors occur during OCR or data extraction (e.g., if a critical field is missing). Implement comprehensive error handling branches.