Full-Stack Engineer (Next.js / Supabase) – Build FinTech & GovTech Intake Workflow

Full-Stack Engineer (Next.js / Supabase) – Build FinTech & GovTech Intake Workflow (Argyle, Plaid, PDF-lib) Overview We are building a specialized, white-labeled compliance and applicant intake platform for commercial multifamily real estate developers and operators in Illinois (affordable housing compliance, property tax relief programs, and inclusionary zoning). The system replaces slow, error-prone paper/PDF income qualification with direct consumer-permissioned financial APIs, a deterministic mathematical rules engine (HUD Part 5 calculations), an operational exception-handling review queue with field-level PII masking, and dynamic PDF generation for official municipal regulatory filings. We have comprehensive wireframes, regulatory mathematical specifications, and architectural documentation ready. We are looking for an experienced Senior Full-Stack Engineer or boutique dev duo to execute the build in clear, milestone-based sprints. Core Architecture & Scope of Work 1. White-Labeled Web Client & Multi-Tenant Core Responsive applicant intake portal built with Next.js (App Router, TypeScript) and Tailwind CSS, deployed on Vercel. Multi-tenant architecture on Supabase (PostgreSQL) with strict Row-Level Security (RLS) policies guaranteeing tenant data isolation. Dynamic white-labeling engine: dynamically themes branding (logo, colors, building parameters) based on URL slug or query parameters. 2. Financial API Ingestion & Document Processing Integrate Argyle (or Pinwheel) Link SDK for verified consumer payroll extraction (gross pay, pay frequency, YTD earnings, deductions). Integrate Plaid Assets Link SDK for real-time bank balance extraction and automated transaction classification (identifying recurring P2P transfers such as Zelle, Venmo, CashApp). Build an automated fallback pipeline using AWS Textract (Queries API) to parse non-digital paystubs, W-2s, and 1040 Schedule C filings for non-connected applicants. 3. Deterministic Rules Engine & PDF Mapping Implement backend calculation logic strictly aligned with statutory HUD Part 5 standards: Annualized run-rate vs. YTD comparison and variance handling. Imputed asset interest calculations (for liquid balances exceeding $5,000). Household Area Median Income (AMI) tier matching against dynamic municipal income schedules. Programmatic PDF generation using pdf-lib (or equivalent) to populate official government PDF forms (e.g., City of Chicago Tenant Income Certification, Cook County Assessor filings) directly from normalized JSON records. Digital signature integration: Dropbox Sign (HelloSign) or DocuSign API for embedded applicant and landlord signature execution loops. 4. Reviewer Portal with PII Masking & Relays Role-restricted operational review portal for manual exception resolution and compliance approval. Field-level PII masking and encryption (dynamic truncation/masking of SSNs, full account numbers, and sensitive financial identifiers). Twilio API integration for automated SMS applicant follow-ups, document request pings, and proxy notifications. Required Tech Stack & Expertise Frontend: Next.js (App Router, TypeScript), Tailwind CSS, React Hook Form, Zod. Backend & Database: Supabase (PostgreSQL, Edge Functions, RLS policies, Vault/pgcrypto). Financial & Third-Party APIs: Direct production experience with Plaid (Assets/Auth), Argyle or Pinwheel, and e-Signature APIs (Dropbox Sign / DocuSign). Document Processing: Proven experience with programmatic PDF form manipulation (pdf-lib) and AWS Textract. Security & Testing: Strong knowledge of multi-tenant data isolation, field-level encryption, role-based access control (RBAC), and deterministic unit testing (Vitest/Jest). Engagement Model & Milestone Breakdown This project is structured as a Fixed-Price Milestone Contract over an estimated 8 to 10 weeks (target total budget: $10,000 – $14,000, with milestones funded and released sequentially upon test-verified deliverables): Milestone 1 ($2,500 – $3,000): Architecture & Shell Supabase multi-tenant schema setup with strict RLS policies and automated isolation tests. Next.js applicant intake shell with dynamic theme routing and secure session handling. Milestone 2 ($3,000 – $3,500): Financial API Ingestion Pipeline Argyle Link and Plaid Link client SDK integration, token exchange, and webhook ingestion state machine. AWS Textract fallback pipeline for manual document upload and parsing. Milestone 3 ($3,000 – $3,500): Deterministic Rules Engine & PDF Generation HUD Part 5 calculation engine with 100% test coverage for income run-rate, YTD, and asset imputation. Dynamic PDF form generation via pdf-lib and automated e-signature envelope triggering. Milestone 4 ($2,000 – $3,500): Reviewer Dashboard, Communication & Deployment PII-masked compliance reviewer dashboard with manual exception resolution workflows. Twilio SMS reminder triggers, end-to-end integration testing, Vercel/Supabase staging and production deployment, and repository handoff. (Note: While this begins as an 8–10 week fixed-price MVP contract, we are open to transitioning into an ongoing technical retainer or long-term lead role as client volume scales.) Candidate Location & Availability Preferred Regions: Latin America (for direct US Central Time overlap) or Eastern Europe / Balkans. Fluent written and spoken English is required. Must have dedicated availability for weekly sprint reviews and synchronous demos during US Central business hours. How to Apply (Screening Instructions) To ensure you have reviewed the specifications thoroughly and to filter out automated agency spam, proposals failing to follow these steps will be immediately archived: Start the very first line of your proposal with: "CHICAGO COMPLIANCE READY". Briefly describe a recent production project where you integrated Plaid, Argyle/Pinwheel, or programmatic PDF form generation (pdf-lib). Include GitHub repos, live demos, or architectural summaries where possible. Briefly explain how you approach multi-tenant Row-Level Security (RLS) in Supabase to ensure zero data leakage across tenants. Confirm your weekly working hour availability and estimated timeline to deliver the full MVP.