tool4seller is an all-in-one Amazon seller platform by TAPCASH INC., serving sellers since 2017. It turns sales, fees, ad spend and inventory into per-SKU profit dashboards — profit & sales analytics, Amazon PPC optimization, product & keyword research, FBA inventory management and AI-assisted listing optimization, on web, iOS and Android, across 22 marketplaces. New: its MCP integration lets sellers query diagnostics, profit, advertising and inventory from AI tools like ChatGPT and Claude.