Build an invoice checker that flags odd patterns

A business analytics graduate used Replit and Claude to create an invoice app that spots large bills, reminders, and duplicates.

Done with Replit AgentClaude Codeยท Intermediate

What they did
Nikhil Thamma, a business analytics graduate, worked through Replit to build Documind. Uploaded invoices were sent to Claude, which pulled out key fields and stored them in SQLite. He then added rules to mark expensive invoices, warn about upcoming due dates, and identify repeated entries. To reduce false alarms, he required at least three invoices per vendor and added low, medium, and high confidence labels.
How it went
On 130 simulated coffee-shop invoices totaling $91,796, the system found four issues, including an $875 duplicate and a 60% jump in bean costs. False positives dropped from 40% to around 15%.
Tips
This works as a single-user MVP, not a finished accounting system. Extraction is much better on clean invoices than on handwritten pages or bad scans, and there is no human review layer.

Try it yourself with Replit Agent

Help me build a simple invoice app in [Replit or similar] that imports invoices from [CSV, PDF uploads, or sample files], extracts key fields into [SQLite or another database], and checks for [duplicate bills], [high-value invoices above a chosen amount], and [payment due dates]. Use [low/medium/high] confidence labels and require at least [number] invoices per vendor before flagging a price change. Show me the flagged items and draft any reminder messages, but stop and ask for my approval before sending anything, deleting anything, or submitting anything. First, create a small demo set of about [number] invoices and show the results.

Fill in the [brackets]. Agents can make mistakes, so review anything before it is sent, paid or deleted.

Read the original on medium.com โ†—

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