Full-Stack Development - Financing Web Platform (4 Portals)

We are a finance company in seeking an experienced development team to build a secure, web-based platform consisting of four integrated applications: (1) an Agent/Partner Portal for insurance brokers to onboard clients (personal and commercial wizards with OCR document capture and digital ID verification), generate financing quotes via API, and execute agreements by print or e-signature; (2) an Admin Portal for our staff covering system configuration, maker/checker verification, two-tier approvals, collections and notifications; (3) a mobile-first Client Portal for statements, balances and online card payments; (4) and a digital onboarding journey (web plus a WhatsApp-style conversational flow) that takes a client from invitation through e-signature and payment. A detailed technical specification is ready, including 28 screen mock-ups, field-level validation, a full data model, quote lifecycle and integration contracts (quoting API, OCR, identity verification, e-signature, payment gateway, email/SMS/WhatsApp notifications, and SFTP file exchange with a bill-payment provider). This is a financial application, so demonstrable experience with security best practices is essential: MFA, role-based access with row-level data scoping, encryption at rest, immutable audit trails, OWASP ASVS Level 2, and PCI-aware payment handling via a hosted gateway. The build must be a responsive SPA (React or Vue with TypeScript preferred) on a stateless REST API with a relational database (SQL Server), delivered in four phases — design, clickable wireframes, iterative development with requirement traceability, and QA including penetration testing. In your proposal, please describe comparable fintech or insurance related platforms you have delivered, your proposed stack and team composition, indicative timeline and budget range, and your approach to UAT and post-launch support. Full specification shared with shortlisted candidates under NDA.