Senior Backend Engineer

• Architected the Agency Handy multi-tenant SaaS platform from inception, providing technical leadership to a team of 3 backend engineers. • Designed a high-reliability webhook notification system using BullMQ with per-tenant configurations, exponential backoff retries, and dead-letter queue fallback. Processing thousands of events daily at P99 < 800ms. • Built AWS-native distributed infrastructure: SQS for durable event ingestion, Lambda workers for stateless processing, EventBridge schedulers for deferred job re-queuing, enabling fault-tolerant async workflows at scale. • Engineered a flexible custom field and checkout-flow engine, allowing agencies to deploy bespoke forms and control client on-boarding without engineering involvement. • Integrated Stripe Connect and PayPal Partner for multi-tenant payment processing, supporting sub-merchant onboarding, payout splitting, and secure transactions across hundreds of agency accounts. • Implemented SES/SNS-backed transactional email with a module-scoped dynamic variable templating engine, enabling branded agency communications at scale. • Led Slack integration enabling real-time workflow notifications and automation hooks, reducing manual overhead for agency teams.

• Architected a multi-tenant e-commerce platform with custom domain routing (Caddy), delivery integrations (Paperfly, Pathao), and advanced analytics dashboards. • Designed and continuously evolved full database architecture (MySQL) to support new features, third-party integrations, and scale demands. • Led strategic partnership discussions and technical integration initiatives with third-party service providers to ensure alignment with platform objectives. Led the integration with bKash, Paperfly, Pathao, SSLCommerz. • Built a campaign management system enabling merchants to design and execute targeted customer acquisition campaigns with performance tracking. • Implemented automated CI/CD pipelines via GitHub Actions, enabling safe and continuous delivery across all environments.