Hi, I'm

Sean Mercier

Senior Software Engineer crafting robust, scalable solutions with 9+ years of experience in Python, C#, and AWS cloud environments.

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About Me

Professional Summary

Experienced Senior Software Engineer with 9 years specializing in designing and building robust, scalable software solutions.

I work primarily with Python, C#, and AWS cloud environments, focusing on developing microservices, APIs, and data pipelines that deliver significant cost savings and efficiency improvements.

As a collaborative team member, I pride myself on strong stakeholder communication and mentoring experience. I'm passionate about writing clean, maintainable code and staying current with modern software engineering practices.

9+ Years Experience
30+ Projects Delivered
10+ Technologies
Expertise

Technical Skills

Technologies and tools I work with to build scalable solutions

Languages

Python Advanced
C# Advanced
Java Intermediate

Frameworks

Flask
.NET
Entity Framework
Vue.js
Bootstrap

Cloud & DevOps

AWS
Azure
Kubernetes
Docker
Jenkins

Databases

SQL Server
Snowflake
DocumentDB

Tools & Technologies

Jack Henry PowerOn
RabbitMQ
Kafka
Apache NiFi
Selenium
Git
Career

Professional Experience

My journey building software solutions that make an impact

Senior Software Engineer

Grow Financial Credit Union

Sep 2024 - Present Current
  • Leading modernization of legacy .NET Framework applications integrated with Jack Henry Symitar core banking system
  • Migrating legacy SymXchange-based applications to Azure Cloud using .NET 8 LTS
  • Building automation solutions using Jack Henry PowerOn to interface with the core banking system
  • Developed PowerOn scripts for loan graduation workflows and credit card product updates
  • Implementing cloud-native architectures to replace on-premise legacy systems

Senior Software Engineer

Connexus Credit Union

Aug 2021 - Sep 2024
  • Promoted from Software Engineer to Senior Software Engineer (Aug 2022) for exceptional performance
  • Led modernization of Institutional Lending App - migrated legacy C#.NET to Python microservices on AWS
  • Architected & built 5 domain-specific APIs, reducing manual processing and errors
  • Developed ~30 AWS Lambda functions automating loan, fee, and data-ingestion workflows
  • Built membership onboarding API handling ~100/day with near-perfect uptime
  • Created loan purchase pipeline saving ~$65K/week in vendor costs
  • Reviewed ~60% of production code, ensuring best practices and high quality

Software Engineer I & II

Skyward Inc.

Jan 2016 - Aug 2021
  • Promoted from Engineer I to II by senior-engineer review, demonstrating strong system design skills
  • Built and maintained 15+ state/federal compliance reports, liaising with district stakeholders
  • Created Selenium UI-tests, improving reliability and catching bugs early
  • Developed monitoring tools for proactive error alerts, boosting uptime
  • Mentored juniors on SQL and custom ORM, elevating team proficiency
Portfolio

Personal Projects

Side projects where I explore new technologies and solve interesting problems

AI Coloring Book Generator

Full-stack application that uses custom LoRA-trained AI models to generate unique coloring book pages. Features secure authentication, payment processing, and cloud storage integration.

  • Custom LoRA-trained AI models for unique page generation
  • Managed Auth0 authentication and Stripe payments
  • Integrated DigitalOcean Spaces for asset storage
Flask Vue.js Auth0 Stripe DigitalOcean

AI-Powered Daily Motivation SMS

Automated service delivering personalized AI-generated motivational quotes and images via SMS. Built with a focus on security and reliability.

  • Daily AI-generated quotes & images via SMS using Twilio
  • Hosted on DigitalOcean with custom VPN/firewall
  • Secure image generation pipeline
Flask Python Twilio DigitalOcean
Background

Education

Academic foundation and continuous learning

BS Computer Science

Minor in Philosophy

University of Wisconsin-Oshkosh 2016

Graduate Coursework

In Progress

Deep Learning & Statistical ML

Arizona State University Spring 2025
Get in Touch

Let's Work Together

I'm always interested in hearing about new opportunities, challenging projects, or just connecting with fellow developers. Feel free to reach out!

LinkedIn Let's connect professionally
GitHub Check out my code