Create Secure Human-in-the-Loop Approval Flows with Postgres and Telegram

🔐 Human-in-the-Loop Approval Flow (n8n + Postgres + Telegram)

👥 Who’s it for

Teams that need a manager approval step before a ticket or request can change status. Great for internal ops, IT requests, or any workflow where “a human must sign off.”

⚡ What it does

• 📨 Manager receives approval/reject link
• 🔑 Link is signed with HMAC + expiry (secure & tamper-proof)
• 🗄️ Postgres updates the ticket status
• 📝 Audit trail records every decision
• 📲 Telegram notifies both manager and requester
• ⏰ Expired or invalid links trigger alerts and logs

🛠 Requirements

• n8n instance (self-hosted)
• Postgres database (with tickets, ticket_audit, workflow_errors)
• Telegram bot token
• One environment variable set: SECRET_KEY

⚙️ How to set up

1. Set SECRET_KEY in .env
2. Create Postgres tables (SQL provided)
3. Add Telegram + Postgres credentials in n8n
4. Import the workflow JSON
5. Test by opening an approval/reject link in your browser

🎨 How to customize

• Change who the “manager” is (currently hardcoded in the Code node).
• Swap Telegram for Slack or email notifications.
• Extend the audit schema to include more metadata (IP, username).