Marcus T. Delgado

Profile

Senior back-end developer with 8 years building distributed systems and REST/GraphQL APIs across fintech and SaaS products. Specializes in Node.js and Python microservices on AWS, with a track record of reducing API latency by 40–60% through architecture refactors. AWS Certified Solutions Architect with deep experience in PostgreSQL, Redis caching strategies, and CI/CD pipeline design.

Work Experience

Senior Back-End DeveloperMar 2021 - Present

Vantara Financial, Austin, TX

Redesigned payment-processing microservices from a monolith to 11 discrete AWS Lambda functions, cutting average transaction latency from 420 ms to 165 ms and eliminating 3 annual outage events.
Built a real-time fraud-scoring API in Python/FastAPI that processes 2.4 million events per day with 99.98% uptime, preventing an estimated $1.7 M in fraudulent transactions in its first year.
Mentored 4 mid-level engineers through bi-weekly architecture reviews, reducing PR cycle time by 35% and lifting team velocity by 22% over two quarters.

Back-End DeveloperJun 2018 - Feb 2021

Loopwise Technologies, Denver, CO

Developed a multi-tenant GraphQL API serving 180+ SaaS clients, supporting 50 M monthly queries with sub-100 ms p95 response times by introducing DataLoader batching and Redis query caching.
Migrated legacy MySQL schema to PostgreSQL 13, reducing storage costs by 28% and improving complex reporting query performance by 3x through targeted index redesign.
Automated deployment pipelines using GitHub Actions and Terraform, shrinking release cycles from 2 weeks to 3 days and reducing environment-provisioning errors by 90%.

Junior Back-End DeveloperAug 2016 - May 2018

Brightpath Studio, Boulder, CO

Built RESTful APIs in Node.js/Express for a consumer mobile app that scaled from 0 to 85,000 registered users within 10 months of launch.
Implemented JWT-based authentication and role-based access control, closing 6 critical security vulnerabilities identified in a third-party audit.
Optimized PostgreSQL queries and introduced connection pooling via PgBouncer, reducing database CPU utilization by 41% during peak traffic windows.

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