Build an internal customer portal with Stripe billing and QuickBooks integration

We run operations for a small financial-services firm and our team is buried under a stack of tools that don't talk to each other. We need a custom internal tool: a customer portal our clients and staff log into instead of juggling spreadsheets and half a dozen apps. First-phase scope: - A web application (Next.js or similar) with role-based access for admins, staff, and clients. - A Stripe billing integration that saves a card on file and runs autopay, plus ACH payment support. - A QuickBooks integration for nightly reconciliation so our books stay correct. - Light workflow automation and an API integration layer to wire up a few third-party services and replace a fragile Zapier setup that keeps breaking. - An admin dashboard and a client-facing dashboard that read live from our systems, not last week's export. A later phase may add an AI assistant, a chatbot over our own data, so staff can ask a question and get pointed to the right record. This is an ongoing project and we want a senior developer who can own the architecture end to end. Please share a couple of relevant portals or internal tools you've built.