Automate document approvals with multi-level workflows using Supabase & Gmail

Multi-Level Document Approval & Audit Workflow

This workflow automates a document approval process using Supabase and Gmail.

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Who it’s for

• Teams that need structured multi-level document approvals.
• Companies managing policies, contracts, or proposals.
• Medical document need multiple lavel of review and approval.

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How it works

1. Form Trigger – A user submits a document via the form.
2. Supabase Integration – The document is saved in the documents table.
3. Supabase Storage – The document is saved in the bucket.
4. Workflow Levels – Fetches the correct approval level from workflow_levels.
5. Assign Approvers – Matches approvers by role from the users table.
6. Approval Record – Creates an approvals record with a unique token and expiry.
7. Email Notification – Sends an email with Approve / Reject links.
8. Audit Logs – Records every approval request in audit_logs.
9. Repeat - repeat the flow till all the aproval level is comepted

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How to set up

• Configure your Supabase credentials.
• Create tables as per data model given.
• Create a storage bucket in Supabase Storage.
• Connect your Gmail account.
• Adjust approval expiry time (48h default).
• Deploy and test via the Form Trigger.

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Customization

• Add multiple approval levels by chaining workflow_levels.
• Replace Gmail with Slack, Teams, or another notification channel.
• Adjust audit logging for compliance needs.
• Update the endpoint http://localhost:5678/webhook-test/ based on instance and env (remove test if you run in prod)
• Update the bucket name.

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Important steps

1. Form Submit

• Triggered when by submiting form
• Captures form parameters:
  • Title (Document Title)
  • Description (Document Description)
  • file (Document need for approval)

2. Webhook Entry Point

• Triggered when an approver clicks the Approve or Reject link in email.
• Captures query parameters:
  • token (approval token)
  • decision (approved/rejected)

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3. Approval Data Retrieval & Update

• Fetch approval record from Supabase (approvals) using token.
• Update approval status:
  • Approved → moves to next workflow level or final approval.
  • Rejected → document marked as rejected immediately.
• Records acted_at timestamp.

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4. Decision Check

• IF Node checks whether the decision is approved or rejected.
• Reject Path → Update document status to Rejected in documents.
• Approve Path → Continue workflow level progression.

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5. Workflow Level Progression

• Fetch details of the current workflow level.
• Identify the next level (workflow_levels) based on level_number.

✅ If Next Level Exists:

• Retrieve approvers by role_id.
• Generate unique approval tokens.
• Create new approval records in approvals.
• Send email notifications with approval/reject links.

❌ If No Next Level (Last Level):

• Update document status to Approved in documents.

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6. Audit Logging

• Every approval action is logged into audit_logs table:
  • document_id
  • action (e.g., approval_sent, approved, rejected)
  • actor_email (system/approver)
  • details (workflow level, role info, etc.)

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📨 Email Template

Approval request email includes decision links:

<p>Please review the document:</p>
<p>
  <a href="http://localhost:5678/webhook-test/doc-approval?token={{$json.token}}&decision=approved">✅ Approve</a> |
  <a href="http://localhost:5678/webhook-test/doc-approval?token={{$json.token}}&decision=rejected">❌ Reject</a>
</p> 

Happy Automating! 🚀