Less busywork. More business. Stacks brings your customers, sales, invoices and bookings together, with unlimited users and no per-user fees.

Your next customer shouldn't mean another spreadsheet, another login and another round of typing. Stacks brings sales, email campaigns, invoices and bookings together around one shared customer record. Follow the relationship from first hello to paid invoice, and bring your team along with unlimited users and no per-user fees. Start with all modules on the $0 plan. Connect AI agents through MCP or REST API with scoped permissions.