Bookkeeping and FBA Shipment App with Claude for Amazon Sellers
What they did
Cancelled InventoryLab and Sellerboard and built his own bookkeeping software with Claude (mostly Opus 4.5, perfected with Opus 5.5). It tracks Amazon, Walmart and eBay sales, refunds, reimbursements, expenses, shipping costs, inventory and cash flow, and he creates FBA and WFS shipments inside it.
How it went
He says the best part is that 'when something breaks, Claude fixes it that day.'
We only report what the source says. Results are self-reported unless noted.
Worth knowing
You become the maintainer. A Reddit seller made a similar point about building your own versus paying for SaaS.
Copy-paste prompt
Starter prompt (written by us)
Help me design (don't code yet) a small bookkeeping app for my Amazon + Walmart + eBay business. It must track: sales by channel, refunds, Amazon reimbursements, expenses, shipping costs, inventory on hand by SKU with COGS, and cash flow. Propose the data model (tables and fields), what each channel's settlement/transaction report maps to, and the 5 screens I need. Ask me about anything you're unsure of.
The source didn't publish its exact prompt. We wrote this starter so you can try the same workflow. Replace anything in [brackets].