Java Developer

Designed and evolved multi-tenant, high-throughput backend services (Rust & TypeScript) for telecom-scale workloads; defined API contracts, versioning, and backward-compatible rollouts. Established auth & security baselines: OAuth2/OIDC, JWT, RBAC, request signing/verification, audit trails, secret/KMS management; enforced least-privilege across services. Built payment-grade workflows (async queues, retries, idempotency keys, reconciliation) for charging/billing–like processes; eliminated duplicate side-effects through deterministic dedupe. Optimized latency/cost via read-write split, Redis caching, batched I/O, background workers; set SLOs and capacity plans with error-budget tracking. Standardized observability (structured logs, metrics, tracing with OpenTelemetry) and incident response; led post-mortems with actionable remediation. Shipped via CI/CD and progressive delivery (feature flags, canary/blue-green) with IaC; reviewed RFCs/critical PRs and mentored backend engineers in distributed teams. Tech: Rust, TypeScript/Node.js, Java/Kotlin (select services), Postgres/MySQL, Redis, Kafka/RabbitMQ, Docker, Kubernetes, OAuth2/OIDC, OpenTelemetry.

Delivered core business APIs (orders/finance/approvals/reporting) with transactional safety, clear error semantics, and partner-ready docs. Modeled domains & schemas, added indexes/partitions; implemented read models and background jobs for heavy queries. Added authentication/authorization (OAuth2/OIDC, token refresh), session hardening, and audit trails; integrated external systems (banking, invoicing, messaging). Built message-driven components (task queues, schedulers, retry/backoff) with idempotent handlers; established dashboards/alerts and on-call playbooks. Operated multi-stage releases with zero-downtime migrations and rollback plans. Tech: Java/Kotlin, C#/.NET (service integration), MySQL/Postgres, Redis, RabbitMQ/Kafka, Docker, CI/CD.

Shipped features for large-scale consumer apps (feed/messaging/search) on a bi-weekly cadence; collaborated asynchronously with server teams on API specs. Improved client networking & caching for weak-network scenarios; added offline packs and resilient retries. Integrated secure login/SSO, push, anti-abuse telemetry; aligned client metrics with server SLOs (startup, crash-free, ANR). Drove data-informed releases via feature flags and A/B tests; documented integration guides and edge-case handling. Tech: Android (Java/Kotlin), Retrofit/OKHttp, ProGuard, Gradle, A/B, analytics.