Denilson Marcos

Senior Backend Engineer with 12+ years of software engineering experience focused on Java, Spring Boot, distributed systems, microservices and cloud-native architectures. Recent hands-on work with Java 17/21 building resilient REST services, event-driven processing and high-throughput backend platforms on AWS. Strong production mindset across performance optimization, fault isolation, asynchronous processing, caching, database efficiency, container orchestration, CI/CD and troubleshooting.

Experience modernizing mission-critical platforms and optimizing critical algorithms from O(n²) to O(n) while preserving business behavior. Additional experience with distributed data processing and GenAI-assisted enterprise applications.

Senior Software Engineer at Avenue Code (2022-08 – 2026-06)

High-scale Java backend, cloud-native platforms, distributed systems & enterprise AI

• Designed and evolved high-scale backend platforms using Java/Spring Boot, REST APIs and distributed microservices, focusing on service boundaries, maintainability, resilience and production scalability.
• Implemented high-throughput integrations and resilient service communication, using asynchronous/event-driven processing where decoupling improved throughput and protected request-response paths from slow dependencies.
• Applied Redis caching strategies to reduce repeated reads and database pressure in performance-sensitive backend flows, improving the ability of services to handle concurrent demand.
• Built AWS solutions using S3, SQS/SNS, EKS/ECS, EMR, Glue and Athena, combining application workloads with distributed data-processing pipelines.
• Worked with Docker and Kubernetes-based deployments and Terraform-managed infrastructure, supporting cloud-native operation and repeatable environments.
• Automated build and delivery workflows with Git, GitHub Actions and Jenkins, integrating testing and deployment into repeatable CI/CD processes.
• Architected a production Hybrid RAG search capability combining BM25 and dense-vector retrieval with Pinecone and AWS Bedrock (Mistral Large), and built LLM-powered operational assistants using Function/Tool Calling with enterprise REST APIs.
• Applied a production-first mindset to backend design, considering latency, failure modes, downstream availability, data access and operational troubleshooting before implementation choices.

Software Engineer at T-Systems International (2020-01 – 2022-08)

Legacy modernization, Java performance optimization & AWS

• Modernized mission-critical enterprise platforms from legacy application-server architectures to containerized Spring Boot microservices on AWS, reducing dependency on legacy runtime infrastructure.
• Upgraded Java runtimes and analyzed critical processing paths, replacing O(n²) collection/algorithm operations with O(n) approaches where appropriate, reducing processing latency while preserving existing business behavior.
• Used appropriate Java collections and lookup strategies to eliminate unnecessary nested scans, demonstrating algorithmic performance improvement rather than relying only on infrastructure scaling.
• Deployed workloads using ECS/EKS, Fargate and Lambda, selecting container or serverless execution according to application and operational requirements.
• Designed resilient messaging with AWS SQS/SNS and Redis, applying idempotency, retry, DLQ and circuit-breaker patterns to isolate transient failures and avoid cascading service degradation.
• Automated application delivery through Jenkins and GitHub Actions, supporting consistent builds and cloud deployments during modernization.
• Worked on modernization with an emphasis on backward-compatible business behavior, using automated validation and incremental changes to reduce migration risk.

Software Engineer at Banco Boa Vista (2018-07 – 2020-07)

Financial systems, high throughput, Kafka, Redis & production resilience

• Re-engineered a mission-critical financial credit-scoring platform with strict SLA, scalability and reliability requirements, supporting workloads above 1,000 requests per second.
• Modernized synchronous backend processing into microservices and asynchronous event-driven architecture using Apache Kafka, reducing coupling between processing stages and improving workload absorption during demand peaks.
• Applied distributed-processing and messaging patterns so slow or temporarily unavailable downstream components did not block the entire credit-processing pipeline.
• Implemented Redis caching to reduce repeated transactional database access and protect core data stores during high-volume request periods.
• Built resilience mechanisms including retries, exponential backoff and DLQs, allowing transient failures to be retried safely while isolating messages requiring later investigation.
• Applied idempotent-processing concepts to reduce the risk of duplicate effects when messages or operations were retried in distributed workflows.
• Investigated backend behavior from an end-to-end perspective - application processing, queueing, cache and database interaction - to meet performance and availability expectations.

Software Engineer at Petrobras (2013-07 – 2018-07)

Enterprise Java, SOA & mission-critical integrations

• Developed Java enterprise services, REST/SOA integrations and backend components for mission-critical corporate systems with strong reliability and governance requirements.
• Designed integration solutions connecting SAP NetWeaver, Siebel and mainframe platforms, building reusable service interfaces to reduce direct coupling between enterprise systems.
• Worked with synchronous and asynchronous enterprise integration patterns, error handling and service governance in environments where downstream reliability and operational support were critical.
• Built the integration and distributed-systems foundation later applied to Spring Boot microservices, cloud-native backend architecture and event-driven processing.

Postgraduate Specialization in Data Science and Analytics – PUC-Rio (2026)

B.S. in Computer Science