🔬 Route AI-scored approval requests with GPT-4o-mini, Supabase and Gmail
⚡ 18 views · 🔬 Document Extraction & Analysis
Description
Quick overview
This workflow collects approval requests via an n8n form, uses OpenAI (GPT-4o-mini) to summarize and score risk, stores the request in Supabase, emails the right approver via Gmail with approve/reject links, then updates the Supabase record and notifies the requester by email.
How it works
- Receives a new approval submission from an n8n form with request details like type, title, amount, department, justification, and requester email.
- Sends the request data to OpenAI (GPT-4o-mini) to generate a short summary plus a risk score, priority, and suggested approval level.
- Chooses an approver email and approval level based on amount thresholds and the AI risk score, then combines the AI output with the original form data.
- Creates a new row in the Supabase
approval_requeststable with the request details, AI fields, and a generated request ID set topending. - Builds approve/reject URLs that point to a webhook and emails the approver via Gmail with the request summary and one-click action links.
- Accepts the approver’s click on the approval webhook, updates the matching Supabase record to
approvedorrejectedwith audit details, and emails the requester the final outcome via Gmail.
Setup
- Add OpenAI API credentials and ensure the model selection (gpt-4o-mini) is available in your OpenAI account.
- Add a Supabase credential and create an
approval_requeststable with columns that match the fields written by the workflow (for example request_id, status, approver_email, approval_level, ai_summary, risk_score, and priority). - Add a Gmail OAuth credential for sending emails to approvers and requesters.
- Update the webhook base URL used in the approve/reject links to your n8n instance URL and ensure the
approve-actionwebhook path is reachable from email recipients. - Replace the hardcoded approver email addresses (manager/finance_head/director) with real inboxes for your organization.
Additional info
How To Customize Nodes
Easy Changes
- Form fields: Edit “New Approval Request Form” → add/remove fields
- AI rules: Modify prompt in “Analyze Risk Priority” node
- Amount thresholds: Update expressions in “Prepare AI Form Data”
- Approver emails: Change ternary logic in approver_email field
- Email templates: Edit HTML in Gmail nodes
Advanced Customization
- Add Slack/Teams: Replace Gmail nodes
- Multi-approver: Add sequential webhooks
- Custom fields: Extend Supabase schema + form
- Reporting: Add cron trigger for dashboard data
Add-ons
Immediate Extensions You Can Try
- Telegram notifications (parallel to Gmail)
- Slack channels per department
- Sequential approvals (Manager → Director)
- PDF generation of approved requests
- Weekly reports to finance team
Enterprise Features You Can Consider
- Role-based access via n8n RBAC
- Multi-tenant (separate Supabase schemas)
- Custom branding on forms/emails
- Integration with HRIS/Payroll systems
Use Case Examples
- Purchase Orders: Laptops, software licenses, office supplies
- Expense Approvals: Travel, client dinners, training courses
- Document Sign-off: Contracts, proposals, policy updates
- Internal Requests: Vacation, equipment, remote work setup
- Vendor Onboarding: New suppliers, service contracts
- Budget Reallocation: Department transfers, project funding
- Overtime Authorization: Weekend work, emergency coverage
Troubleshooting Guide
| Issue | Possible Cause | Solution |
|---|---|---|
| Form not submitting | Workflow inactive | Activate workflow, use Production URL |
| AI returns plain text | Markdown parsing failed | Check “Extract AI JSON Response” code |
| Webhook 404 error | Test URL used | Activate workflow, copy Production webhook URL |
| Email not sending | Invalid OAuth2 | Reconnect Gmail credentials |
| Supabase insert fails | Missing table/columns | Run schema SQL exactly as provided |
| ”Requester Email Valid?” skips | Empty requested_email_by | Fill email field in form |
| Wrong approver | Amount thresholds | Verify logic in “Prepare AI Form Data” |
Need Help?
Our n8n workflow developers at WeblineIndia can help you with:
- Custom approval workflows (multi-stage, conditional routing)
- Enterprise integrations (ERP, HRIS, accounting)
- White-label form builders
- Performance optimization for 10K+ daily requests
đź”— Nodes Used
Webhook, Gmail, Supabase, n8n Form Trigger, OpenAI
đź“Ą Import
Download workflow.json and import into n8n:
Workflow menu → Import from File