Loan Management Platform

Problem

Lending operations mixed manual spreadsheet checks with ad-hoc tools. Repayment schedules, partial disbursements, and edge-case scenarios were error-prone and hard to audit.

Solution

Modeled loan lifecycle and repayment rules in a dedicated service layer with clear APIs, PostgreSQL for durable state, and a Nuxt dashboard for approvals, balances, and next actions.

System architecture

1. Browser → Nuxt UI (SSR + client islands for interactive tables).
2. API layer: REST endpoints versioned under `/api/v1`, auth at gateway.
3. Application services: loan lifecycle, repayment engine, approval rules—no business rules in controllers.
4. Persistence: PostgreSQL with explicit migrations; money movements tied to immutable event rows where applicable.
5. Observability: structured logs on state transitions (approved, disbursed, repaid) for support and audits.

Backend logic

• Repayment schedules computed from principal, rate, and term with idempotent recalculation when terms change mid-flight.
• Partial disbursements and multi-draw scenarios mapped to ledger-like entries so balances always reconcile.
• Approval workflows as state machines: invalid transitions rejected at the service boundary, not only in the UI.
• Reporting queries isolated from OLTP hot paths (read replicas or materialized summaries where scale demands).

Tech stack

Outcome / impact

• Ops teams spend less time reconciling spreadsheets and more time on exceptions.
• Engineers can extend new loan products by adding rules in one place instead of patching scattered scripts.
• Foundation for regulatory-style audit questions: who approved what, when, and under which policy version.

Result: Automated loan repayment logic across multiple disbursement scenarios, reducing manual calculation errors and giving ops a single source of truth.

Related writing

• Designing scalable loan systems →
• Handling financial logic in backend systems →
• Clean architecture for enterprise apps →