How it Works

This workflow automates Invoice & Payment Tracking (with Approvals) across Notion and Slack.

• Ingest — You drop invoices/receipts (PDF/IMG/JSON) into the flow.

• Extract — OCR + parsing pulls out key fields (invoice no, vendor, currency, totals, receipt paid amount/date).

• De-dup & Match — We canonicalize vendor + invoice_no and search Notion:

  • Primary match: Invoice No (+ optional Currency / Vendor (Canon)).
  • Fallback: uses document Amount Total and dates.

• Decide the action

  • create_unpaid — new invoice (no payment).
  • create_paid — new invoice fully paid (unverified).
  • create_partial — new invoice with a first partial payment.
  • update_partial — add a partial to an existing invoice.
  • update_mark_paid — mark existing invoice paid in full.
  • manual_review — currency mismatch / overpayment / ambiguous.
  • archive — push to archive logs (from manual review).

• Slack approvals (one-click) — A message shows previous paid, this receipt, new total, and Approve buttons (links to a Wait for Webhook resumeUrl). Reviewer picks: Approve Partial / Mark Paid / Manual Review / Archive.

• Notion updates

  • We only write editable fields: Paid Amount (number), Status (select), Last Payment Date (date).
  • Formulas (e.g., Amount Total, Amount Due) recompute automatically.
  • Receipts are saved in a Receipts DB and related back to the invoice.

• Notifications & duplicates — If duplicates are detected, Slack posts a simple list with clickable invoice names.

• Archiving — From Manual Review, Archive goes straight to Archived Invoice DB (and optional Archived Source File DB) as a log entry—no pre-checks needed.

Set up Steps

Prerequisites

1. Notion DB
2. 4 Slack Channel (Invoice Input , Notification , Manual Review , Duplicate Alert (Optional))
3. AI Model (We use Claude 3.5 Haiku , Feel free to use Latest Model)
4. OCR Parsing (We Used ocr.space , Feel Free to Change into any OCR Parsing you have)

• Create Notion DBs:
  • Invoice DB : Title Invoice No; Number Paid Amount (editable); Select Status; Dates (Issue/Due/Last Payment Date); Formulas:
    • Amount Total = round(Subtotal - Discount Amount + Tax Total, 2)
    • Amount Due = max(0, round(Amount Total - Paid Amount, 2))
  • Receipts DB : Invoice No, Vendor, Paid Amount (number), Currency (select), Paid Date (date), Receipt No, Source URL; Relation → Invoice.
  • Archived Invoice DB : Invoice No, Vendor, Reason, Source URL, Original Page ID, Archived At (date).
  • (Optional) Source File / Archived Source File DBs.
  • Share all DBs with your Notion integration (Add connections).
• Add credentials in n8n: Notion (integration token) and Slack (bot token). Invite the bot to your channel.
• Import the workflow/template: Set each Notion node’s Database ID and each Slack node’s Channel/Credential.
• Map updates: In the Invoice Update Page node, map Paid Amount , Status , Last Payment Date. In Create Receipt , map Invoice relation + receipt fields.
• Test: Run with a sample invoice/receipt → click a Slack button → verify Invoice/Receipt updates in Notion → try Archive from Manual Review.