Catch duplicate invoices from Gmail before they get paid twice

Scans invoice emails automatically and alerts you in Slack before a duplicate invoice slips through.

How the work actually flows

It branches. Exactly one path is taken.

Pattern: Exclusive Choice (4)

flowchart TD trig>"invoice email received"]:::trig s0["extract invoice details"]:::svc s1["check against invoice log"]:::task trig --> s0 s0 --> s1 gx{"× is invoice a duplicate"}:::gate s1 --> gx p00["send slack alert"]:::task gx -->|"duplicate found"| p00 p10["log invoice in sheet"]:::task gx -->|"new invoice"| p10 p00 --> out p10 --> out out[/"duplicate invoices caught before payment"/]:::out pay{{"prevents double payments automatically"}}:::pay out --> pay classDef task fill:#e7f6fe,stroke:#34b8f0,color:#2c2a29 classDef svc fill:#f6f8fa,stroke:#7c8795,color:#2c2a29 classDef mi fill:#e7f6fe,stroke:#0079a8,color:#2c2a29,stroke-width:2px classDef human fill:#fff,stroke:#0079a8,color:#0079a8 classDef store fill:#f6f8fa,stroke:#0079a8,color:#2c2a29 classDef trig fill:#00a4eb,stroke:#0079a8,color:#fff,font-weight:bold classDef trigtime fill:#00a4eb,stroke:#0079a8,color:#fff,font-weight:bold classDef trigdata fill:#8ad4f5,stroke:#0079a8,color:#06314c,font-weight:bold classDef gate fill:#fff,stroke:#e8a23d,color:#6b4708,font-weight:bold classDef out fill:#1f9d6b,stroke:#167a53,color:#fff,font-weight:bold classDef pay fill:#06314c,stroke:#021f33,color:#fff
Starts itA stepAn outside serviceOne path onlyResultPayoff
Build size
Advanced

A larger build with multiple systems, AI reasoning, and custom rules.

Business functions
Email AutomationMessaging & NotificationsDocument Processing & OCRImage & Media ProcessingSpreadsheet & Database OpsFinance & Accounting
Connects
GmailSlackGoogle Sheets

The problem it solves

Vendors sometimes resend the same invoice, and if nobody catches it, you end up paying twice. Manually cross-checking every invoice number against your records is tedious and easy to skip when you're busy. By the time a duplicate payment is noticed, the money is already gone.

Who it fits

Finance and accounting teams who process vendor invoices by email and want to avoid double payments.

How it works

  1. A new email labeled as an invoice arrives in Gmail
  2. The PDF attachment is read by AI to pull out the invoice number and amount
  3. That invoice number is checked against your master finance spreadsheet
  4. A duplicate triggers an instant Slack alert
  5. A genuine new invoice is logged in the spreadsheet automatically
What you get

Duplicate invoices caught before they're paid twice

You get an instant Slack alert before a duplicate invoice can slip through and get paid twice.

What you get

An always up-to-date invoice log, plus an instant alert whenever a duplicate is caught.

What you need

A Gmail account, a Slack workspace, a Google account for Sheets, and an AI document extraction subscription.

We can build this. But should you?

The hard question is not how to build it. It is whether this is the right thing to build first.

That is what a Fractional Chief AI Officer figures out with you, before anyone writes a line of code.

Let's Talk Strategy

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