Custom CRM-Linked Accounting Database

I want to replace my scattered spreadsheets with a unified database-driven accounting platform that speaks to Salesforce in real time. At its core the system must let me:

• Store and maintain complete customer profiles
• Create, issue, and post invoices (tax, discounts, partial payments included)
• View a full invoice and payment history with searchable filters and audit logs
• Keep all records automatically in sync with Salesforce the moment data changes

Three permission tiers are required—Admin, Manager, and User—so role-based access control has to be baked in from the start. Security (encryption at rest and in transit), scalability (think growing client list and transaction volume), and an intuitive web UI are priorities.

I’m open to your recommended stack, but it should connect smoothly to Salesforce APIs, handle accounting rules reliably, and be maintainable for future feature additions. Please outline your proposed architecture, key milestones, and any similar projects you’ve delivered so I can gauge fit and timeline.