Three systems that earned their keep.
Case studies in caching, payments, and AI-driven creative — written as architecture, not slideware.
Multi-layered caching & health-check fabric
A production service was buckling under read load and cold-start latency spikes; downstream dependencies failed silently.
Designed a tiered Redis cache in front of MongoDB with write-through invalidation, request coalescing, and per-key TTL policies. Layered high-availability health-check APIs that gossip status across nodes and trip circuit breakers automatically.
p99 latency cut by ~70%, zero-downtime deploys, and self-reported failures before customers notice.
Cross-border payments for a service platform
An e-commerce / service platform needed to accept both local Bangladeshi payments and international cards without rebuilding checkout twice.
Built a unified payment abstraction over UddoktaPay and IT Pay BD for local rails, plus international card processors, with idempotent webhooks, signed callbacks, and a reconciliation worker that closes the loop between gateway and ledger.
Single checkout for every customer, automated reconciliation, and a clean audit trail for finance.
AI-assisted high-conversion creative engine
Paid acquisition needed a steady stream of video + audio ads, fast, without ballooning creative budget.
Composed a pipeline of LLM scripting, automated voice synthesis, and template-driven video assembly — driven by Gemini CLI and custom LLM integrations — with Facebook Ads feedback loops scoring creatives for retention and CTR.
Weekly creative output multiplied, with measurably higher conversion on top performers.