Insurance Claim Processing System

Medical insurance claim processes are traditionally slow, paper-heavy, and confusing. Patients are left in the dark about their status, and insurance audit agents waste hours cross-referencing documents.

A secure, multi-tenant digital platform must isolate patient records, restrict administrative capabilities to authorized claims agents, and provide status tracking.

I developed a robust claim management portal using NestJS and React:

• NestJS REST API: Built a modular backend with NestJS, utilizing PostgreSQL and TypeORM to manage records and audit trails.
• Role-Based Authentication: Implemented JWT-based role guards (Patient, Claim Agent, Admin) to prevent unauthorized privilege escalation.
• Interactive React Dashboard: Designed a clean dashboard displaying graphical status trackers, invoice upload fields, and review panels.

Managing claim statuses and matching them to document audit trails in PostgreSQL started to cause sluggish load times on the Agent dashboard under simulated bulk uploads.

I analyzed the database operations and found that the query engine was executing nested joins across multiple tables without index support.

I resolved this by adding composite indexes on patient_id, claim_status, and claim_date columns. Furthermore, I rewrote the dashboard fetch endpoints to use raw PostgreSQL Common Table Expressions (CTEs), reducing dashboard page render fetch latencies from 950ms to 40ms.

Related Reading: I've written a comprehensive architectural guide analyzing the security and scalability trade-offs between stateless tokens and database sessions. Read it here: JWT vs Sessions: What I Learned Building Apps.