Open to opportunities

Mario Reis

@marioreis

Senior backend developer specializing in AWS/GCP cloud services, scalable microservices, and observability-driven reliability.

Brazil

Message

What I'm looking for

I’m looking for a senior backend role where I can modernize cloud systems, build reliable distributed services, and strengthen observability. I want teams that value agile execution, quality, and measurable reliability improvements.

I’m a Senior Backend Developer who modernized mission-critical payment and e-commerce infrastructure using AWS serverless and distributed patterns. I built and operated AWS Lambda, API Gateway (custom authorizers), DynamoDB, SQS, and S3, adding CloudWatch logging and custom exception handlers to make production health visible and actionable.

I also deliver cloud-native, multi-tenant systems on GCP and Kubernetes, including real-time hotel workflows with Kafka and strong error logging (URL/method/parameters). Across my career, I’ve helped teams raise quality and reliability—replacing legacy components without disruption, improving incident rates and SLA coverage, and hitting Black Friday/Christmas performance targets.

Experience

Work history, roles, and key accomplishments

Senior Backend Developer

Agile Engine

Mar 2025 - Feb 2026 (11 months)

Implemented AWS Lambda/API Gateway, DynamoDB, SQS, and S3 to replace a legacy payment infrastructure supporting B+ annual e-procurement transactions for 6,500 clients. Improved processing speed and system reliability with no service disruption and enhanced observability via CloudWatch logging.

Golang Java AWS Lambda API Gateway DynamoDB SQS S3 Amazon EKS Cloudwatch Redis

Senior Software Engineer

Optii Solutions

Feb 2024 - Nov 2024 (9 months)

Developed Optii Timeline to list hotel employees and their tasks in real time, using multi-tenant and distributed design with per-tenant data isolation. Added contextual error logging and improved operational visibility; contributed to LATAM expansion increasing by 200%.

Kafka Docker Kubernetes Terraform CI CD Jenkins gRPC HTTP Grafana MongoDB

Senior Software Engineer

Casas Bahia

Apr 2019 - Jan 2023 (3 years 9 months)

Led stress testing and monitoring with Dynatrace and performed code refactoring to meet Black Friday and Christmas targets of 100,000 transactions per minute. Developed Consumer Direct Credit Online ($800,000.00 in authorized credit) and helped increase participation from 8% to 20% on the company's billing.

Dynatrace Refactoring Scrum Kanban Grafana MongoDB PostgreSQL Performance Optimization SLA Management

Senior Software Engineer

Rede Piu

Dec 2017 - Mar 2019 (1 year 3 months)

Built key backend products for a payment network startup, including transportation ticket recharge, Outback voucher issuance, and road toll card loading. Contributed to delivery of core payment features across multiple services.

Payment Network Development Transit Ticket Recharge Road Toll Card Loading Payments Domain

Senior Software Engineer

Swiss Re

Jan 2012 - Apr 2016 (4 years 3 months)

Implemented Surety, Liability, Claims, Finance, and Reinsurance modules and participated in adopting agile methodologies. Improved audit grade from C- to B+ and reduced incidents from 430 to 48 while increasing SLA coverage from 23% to 92%.