Skills
  • Backend — Java
    Spring Boot 3.x Play Framework 2.5 / 2.6 OOP & SOLID principles Design Patterns (Factory, Strategy, Observer, Template Method) Clean Code & Refactoring Asynchronous Programming (CompletableFuture, CompletionStage, @Async thread pools) REST API Design & Versioning Spring AOP / Aspect-Oriented Programming Spring Data JPA / Hibernate Hibernate Envers (audit trail) Jakarta Validation MapStruct Lombok JUnit 4 / 5 & Mockito SpringDoc OpenAPI 3.0 / Swagger Flyway database migrations JasperReports / PDF generation JWT / token management Spring Security
  • Backend — Scala
    Play Framework (Scala) Akka actors & Akka Quartz Scheduler Scala Futures & reactive programming ScalaTest & ScalaTest + Play Phantom DSL (Cassandra) SBT build tool Google Guice (DI) HOCON configuration
  • Backend — PHP
    Phalcon MVC framework REST API integration (cURL) DataTables.js server-side processing N+1 query elimination & batch optimization Multi-country gateway configuration management
  • Payment Gateway & Telecom Integration
    Direct Carrier Billing (DCB) protocols SMS-based & MSISDN+PIN subscription flows Webhook / DLR / MO notification handling Two-phase auth (MSISDN + OTP) Mobile network gateway integration (NTH, DIMOCO, Pivot Point, Telenes, Airpay, Allopass, Lily, TeleAudio, Infomedia, HighConnexion, Actel, Dimoco, and more) Partner onboarding documentation & API contract authoring Fraud detection at ingestion (15-min stop, initial-cancel patterns) Revenue / billing calculation & multi-currency tariff logic
  • Databases & Storage
    Apache Cassandra — data modeling, CQL, Phantom DSL, materialized views, paging PostgreSQL — relational schema design, GROUPING SETS, migrations MySQL — query optimization, AWS RDS Redis — caching strategy, cache controller design Flyway — versioned schema migrations Spring Data Cassandra Spring Data JPA Polyglot persistence (Cassandra + PostgreSQL + Redis in one system)
  • Cloud & Infrastructure
    AWS SQS — async messaging, SDK v1→v2 migration, IAM role auth AWS SES v2 — transactional email, MIME attachments AWS S3 — file storage, PDF delivery AWS Cognito — user authentication & identity AWS Kinesis Firehose — analytics event streaming AWS ECS / Fargate — containerized deployment AWS ECR — Docker image registry Docker & Docker Compose EC2 → ECS infrastructure migration
  • Frontend — React / Next.js
    Next.js 16+ (App Router) React 19 TypeScript TanStack Query (data fetching & cache) TanStack Table Zod (schema validation) Radix UI Tailwind CSS 4 Typed API client layer design Form validation & error handling Admin CRUD UI patterns React state management
  • Frontend — Landing Pages & SDK
    Semantic HTML & clean CSS / SCSS Responsive & multi-language landing page design (20+ country/service combinations) RTL layout (Arabic markets) Vanilla JavaScript ES6 modules Gateway API client library design (10+ providers, modular pattern) Campaign status guard (fail-closed pattern) WebP image optimization (3,398 conversions) Service Worker API jQuery & Bootstrap GDPR / legal compliance notices i18n / localization
  • Architecture & Design
    Layered architecture (controller → service → repository) Event-driven architecture (ApplicationEventPublisher, SQS) MVC architecture Configuration-driven design Modular SDK / shared library design Request capture & replay for production troubleshooting Hierarchical validation (cascade cap enforcement) Thread-safe concurrent processing (ReentrantLock) Audit trail design (Hibernate Envers, AOP logging)
  • Testing & Quality
    Unit testing (JUnit 5, Mockito, ScalaTest) Integration testing with embedded Cassandra + CQL fixtures Test isolation in shared Cassandra environments API contract testing Clean Code & SOLID principles Refactoring (50–81% code reduction, service decomposition)
  • Communication & Documentation
    Partner integration documentation (API contracts, webhook flows, MSISDN subscription protocols) OpenAPI 3.0 / Swagger annotation coverage Technical investigation & root-cause analysis write-ups Cross-team coordination during gateway onboarding Production incident response & hotfix documentation
  • Tools & Ecosystem
    Gradle SBT Git / GitLab CI/CD Kamon (metrics) SLF4J / Logback (structured logging) Firebase Affise API Wise API Webpack Terser (JS minification)