n8n: Auto Grade PDFs with OpenAI, Drive, Sheets & Gmail + Telegram

Auto-grade new PDF assignments automatically—then email students and send a daily teacher summary via Gmail + Telegram

This n8n workflow watches a Google Drive folder for newly uploaded PDF submissions, extracts their text with OpenAI, grades them using a rubric stored in Google Docs, records results in Google Sheets, notifies students via Gmail, and delivers a daily grading summary to the teacher through both Gmail and Telegram. Errors are surfaced via Slack.

What this workflow does

• Monitors Google Drive: Triggers when a new PDF file is created in a specified Google Drive folder.
• Extracts PDF text: Downloads the PDF and sends it to OpenAI to extract full plain-text content.
• Identifies submission details: Parses student name, email, assignment title, and course from the filename.
• Loads grading rubric: Fetches the rubric from a Google Docs document URL you configure.
• Generates structured grades: Sends assignment text + rubric to OpenAI to produce a JSON grade with per-criterion scores and three feedback paragraphs.
• Logs to Gradebook: Parses returned JSON (with fallback defaults if parsing fails) and appends a complete record to Google Sheets (your spreadsheet ID and Gradebook sheet name).
• Emails student feedback: Sends a formatted Gmail message including grade, score breakdown, and personalized feedback.
• Sends daily teacher summary: Runs every day at 6 PM, summarizes today’s grading results from the Google Sheets Gradebook, and sends it to the teacher via Gmail and Telegram.

Use cases

• Instructors auto-grading homework PDFs at scale while keeping consistent rubric-based scoring.
• SaaS operators running education workflows that require audit-ready logging in Google Sheets.
• Teachers who want student feedback delivered immediately and a daily rollup for themselves.

Technical details

• n8n trigger: Google Drive new file creation
• Nodes/integrations: if, code, gmail, slack, telegram, google docs (plus Google Drive + Google Sheets)
• External AI: OpenAI for PDF text extraction and rubric-based JSON grading
• Scheduling: Daily summary at 6 PM
• Error alerts: Slack notifications

Setup requirements: Configure Google Drive folder ID, Google Docs rubric document URL, Google Sheets spreadsheet ID + Gradebook sheet name, and connect credentials for Google Drive, Google Docs, Google Sheets, Gmail, Telegram, and Slack.