Salvador
Cruz Alfaro

OCPP PLATFORM — REAL-TIME CHARGING PROTOCOL

• Designed and built the OCPP WebSocket Gateway supporting concurrent persistent connections per charger, identified by ChargePointId, with JWT token and identifier validation at the URL level (wss://host/ws/ocpp/{id}?access_token=...).
• Implemented a Command Handler Engine covering all OCPP IN/OUT commands: BootNotification, StatusNotification, MeterValues, Heartbeat, Authorize (incoming) and RemoteStart/StopTransaction, Reset, ChangeAvailability, GetConfiguration, SetConfiguration (outgoing) — multi-version compatible (1.6, 2.0, 2.0.1).
• Built Session & State Management persisting session state to MySQL (sessions) and Cassandra (high-frequency events) — enabling charger reconnection, full state recovery, and complete audit trail via SessionId (GUID).
• Implemented a Heartbeat Monitoring System for real-time Online/Offline charger detection, integrated with Cassandra status_notifications and alert infrastructure.
• Designed Azure Service Bus event integration publishing StartCharging, StopCharging, MeterValues (initial/final), and session lifecycle events — decoupling the OCPP API, App API, and Billing systems.

MULTI-PAYMENT GATEWAY — STRATEGY PATTERN ORCHESTRATION

• Designed a modular Payment Orchestrator with country-based, currency-aware provider selection — Mexico routes to OpenPay/MercadoPago, global to Stripe — with automatic failover: Stripe → OpenPay → MercadoPago.
• Implemented a Provider Abstraction Layer via IPaymentProvider interface using Strategy Pattern — enabling new providers to be added without breaking existing integrations. Integrated Stripe, MercadoPago, OpenPay, Google Pay (via Stripe), and MasterCard.
• Built idempotent Webhook handlers for payment confirmation — with signature validation, retry logic, and async state management for Stripe and MercadoPago event streams.

ADMINISTRATION API — GEOLOCATION & STATION MANAGEMENT

• Built nearby station search API with lat/long + radius queries, dynamic availability and connector-type filters, and geospatial optimization for map rendering.
• Implemented Map Markers API with bounding-box queries, live availability status, connector type, and power level filters for real-time station map views.
• Designed Favorites system with paginated user-site relationships, optimized reads, and enriched site detail responses.
• Applied Clean Architecture end-to-end: Controllers → MediatR → CQRS Handlers → Repository Pattern → Unit of Work, with standardized ApiResponse<T>, JWT claims-based access, and multi-tenant Account/Company scoping.

• Designed and implemented REST APIs in C#/.NET 8 for recruiting domain operations including CRUD for jobs, candidates, applications, and pipeline stages with bulk rejection workflows.
• Built Kafka consumers and publishers for CandidateEvaluated, CandidateReevaluated, ApplicationUpdated, and webhook events — fully idempotent and race-condition safe.
• Integrated Greenhouse ATS (REST v1/v3 + Webhooks): smart/silent rejection, 24h deferred email delivery, user synchronization, and candidate merge handling.
• Implemented Snowflake-enriched recruiter dashboards (Throttle Phase 2) with dynamic filtering, sorting, pagination, and in-memory enrichment strategies.
• Designed scheduled CRON automation: Employee Anniversary processing, hardline business rule enforcement, "Unable to Contact" and "Repeat Abandoned Chatbot" auto-decisioning.
• Implemented duplicate detection and merge workflows with resume parsing integration — safe, traceable, idempotent across distributed pipeline writes.
• Led technical code reviews and PR feedback loops enforcing Clean Architecture boundaries, reducing hardcoded logic, and strengthening test coverage.
• Diagnosed and resolved production race conditions using Splunk telemetry; improved webhook-driven pipeline reliability in production.
• Built comprehensive unit and integration test suites using xUnit, Moq, and FluentAssertions for ApplicationStatusService, DashboardJobAppService, and dynamic FilterExpression engine.
• Implemented Claude Code as AI development orchestrator with MCP integrations connecting Slack, Jira, Azure DevOps, and GitHub — enabling AI-assisted ticket triage, PR review automation, pipeline status queries, and cross-tool context propagation directly from the development environment.
• Designed and deployed Cowork agents and custom Skills to automate recurring team workflows: standup summaries from Slack threads, Jira issue creation from engineering discussions, PR description generation from GitHub diffs, and Azure DevOps pipeline monitoring — reducing manual coordination overhead across the distributed team.
• Authored reusable MCP-based Skills encapsulating domain-specific knowledge and workflow patterns, enabling consistent context-aware AI assistance for code review, architecture documentation, and incident triage without leaving development tools.

CLIENT · PUBLIX (US GROCERY RETAIL)

• Built .NET 8 scheduling management module in Clean Architecture with Mediator Pattern — handling store closures, reschedules, cancellations, LIFO strategy, and new activations.
• Created FluentValidation frameworks for 5 distinct change types (Add, Close, Reschedule, Cancel, LIFO) — each with independent validators following SRP.
• Implemented Excel OADate and MM/dd/yyyy format support for scheduling imports; async processing with cancellation tokens for responsiveness.

CLIENT · PERFICIENT INTERNAL (AI PLATFORM)

• Built Azure Functions pipeline for document processing with Document Intelligence — OCR extraction and structured data retrieval from requirement documentation.
• Integrated Azure OpenAI GPT models for semantic document search, connecting Angular 18 frontend to Azure cognitive services stack via REST APIs.

CLIENT · AUTOMOTIVE / WARRANTY PLATFORM

• Led MongoDB-to-Firestore migration for vehicle data APIs — redesigned data access layer, implemented simulated test data, achieved 80%+ unit test coverage.
• Proposed and built Hexagonal Architecture with MediatR for vehicle warranty purchase platform — domain, use cases, application, infrastructure cleanly separated.

• Led Payroll service migration from .NET Core to .NET 6 for Disney/ESPN — improved performance and maintainability, preserved all business logic with full test coverage.
• Designed RESTful APIs with Hexagonal Architecture and MediatR — clean separation of controllers, use cases, application, and infrastructure layers.
• Integrated Auth0 and AWS (S3, EC2, Lambda, CloudWatch) for scalable deployment, logging, and serverless processing across multiple environments.
• Built Angular 12–14 components with reactive patterns and inter-component communication via observables for enterprise entertainment applications.
• Used Key Vault, RabbitMQ, Redis, and Docker for secrets management, event handling, data caching, and containerized deployments.
• Mentored junior developers through code reviews, technical guidance sessions, and pair programming across distributed Mexico/US teams.

• Led Azure DevOps full setup: branch management, multi-environment CI/CD (Dev → QA → PreProd → Prod), custom build agent scripting and optimization for multiple services.
• Integrated Azure Cognitive Services for facial recognition, liveness detection, OCR, document parsing, face comparison, anti-spoofing, and AFIS biometric enrollment.
• Built multi-platform frontends: Xamarin (iOS/Android), Angular 12, Blazor, and React JS — covering mobile onboarding, web dashboards, and internal operations tooling.
• Designed hybrid cloud architecture spanning Azure and AWS: Blob Storage for documents, App Services for deployment, S3 for assets, Lambda for serverless processing.
• Conducted data mining and transformation using SSIS, SQL Server, and MySQL for reporting and analytics pipelines across Mexico and US operations.
• Provided consulting, mentoring, and hands-on training to development teams, and enforced company-wide development standards.

• Designed and built SADA — revenue management and assurance system for ATM-based collection and payment operations for Banco Azteca.
• Implemented SADA Service Orders — multiplatform Xamarin app tracking field technician orders in real time with full lifecycle management.
• Built driver's license enrollment system via ATMs with AFIS biometric fingerprint integration — enabling license issuance through existing ATM infrastructure.
• Designed SyGenTS workflow engine for orchestrating collection and payment device components, coordinating hardware interactions programmatically.
• Developed native hardware drivers in .NET Core/C# for all ATM peripherals: banknote/coin dispensers, card readers, fingerprint, iris, cameras, NFC, and payment terminals.
• Created development standards, modeled multiplatform mobile architectures, and provided consulting and staff training across the engineering organization.

• Lanzadera / Bimbo Mexico: Mobile route management system for on-route product collection and delivery, plus operational dashboard — Xamarin, .NET Core, Angular, Blob Storage.
• Grupo Autofin / Bajaj Motos: Warranty request, acceptance, and rejection system + collections system — .NET Framework 4, WCF, AS-400, WPF, Xamarin.
• ArqInSoftware: Financial system, mobile loan collector app, house automation system, restaurant management system, and cleaning service operator organization platform.
• OOASAPAT (Water Authority): Managed IT infrastructure, databases, and collection software. Built CONAGUA annual reports automation, improved collection system, and mobile water meter reading app. Migrated legacy systems to .NET Framework 4.