Layers — Private Loan Manager

FinTech · shipped · 2026 · Client: Personal

Private two-owner app to track borrowers, loans, payments, collateral, and account balances with reminders.

The problem

Two partners lending from personal savings tracked borrowers, loans, interest, and repayments by hand across notes and memory. Outstanding balances, due dates, overdue amounts, and cash reconciliation were error-prone and hard to keep in sync.

The solution

A Next.js App Router application backed by Supabase (Postgres, Auth, row-level security hardened to the two owners). All money math lives in pure, single-source calculation functions; reads run through React Server Components and writes through zod-validated Server Actions.

Key features

• Fixed-return and interest-based loans with a transparent completed-months interest model
• Borrower and loan history with on-time vs. late completion analytics
• Manual accounts ledger with derived balances for cash/bank reconciliation
• Loan security/collateral tracking with held/returned status
• Dashboard totals plus due-soon and overdue reminders

Impact

• Replaced scattered manual notes with a single source of truth for balances and overdue status
• Automated interest, outstanding, and delay math, removing hand-calculation errors
• Internal ledger enables reconciliation of on-paper balances against real bank and cash
• Per-borrower credit history supports more informed lending decisions

Tech stack

Next.js 15, React 19, TypeScript, Tailwind CSS, shadcn/ui, Supabase, PostgreSQL, Row-Level Security, Server Actions, Zod, date-fns

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