Case studies from my work as a Product Engineer at Digiicampus, a multi-tenant platform for educational institutions. Each write-up covers the problem, the approach, and the measurable outcome.
Built end-to-end faculty hiring for colleges (job posting, application, scoring, approval, offer and onboarding handoff) as a new service with its own public candidate portal.
Built a configurable performance-appraisal engine inside a multi-tenant Spring Boot monolith: policies, cycles, multi-reviewer scoring, and KPIs computed from live data in other modules.
Designed a centralized hub that lets users link accounts across independent tenants using union-find transitive closure and HMAC-signed JWT flows.
Replaced sequential integer IDs across a multi-tenant platform with FF1-encrypted equivalents to prevent enumeration attacks, without breaking schemas or queries.
Built a biometric attendance flow with geofenced locations, multi-layer timezone resolution, and server-side timestamp enforcement to prevent device-time fraud.
Audited 15+ Redis clusters, upgraded from 6.2.6 to 7.1.0 to avoid Extended Support fees, right-sized instances based on actual usage, and fixed cache anti-patterns in application code.