I’m building a web-based SaaS platform that gives our corporate teams complete control over user accounts while speaking fluently to the rest of our tech stack. The heart of the app must cover secure user registration and login, granular role-based access control, and detailed activity tracking so every click is auditable. Equally important is the integration layer. The service needs to exchange data in real time with our CRM, ERP, payment gateway, and the in-store POS system we already run. Please design the APIs so additional connectors can be added later without touching the core logic. Tech direction is open, provided the solution is multi-tenant, scalable, and shipped with thorough automated tests. OpenAPI (Swagger) docs for every endpoint and a clean, modern browser interface are non-negotiable. Deliverables • Responsive web interface covering all user and admin workflows • REST API exposing every feature, documented in OpenAPI • Working connectors for one CRM, one ERP, one payment gateway, and our POS demo environment • Deployment scripts plus a basic CI/CD pipeline • Developer documentation and a concise user guide I’ll supply sandbox credentials for the third-party systems once we kick off. When you respond, outline your preferred stack, project timeline, and examples of similar SaaS work you’ve shipped.