Senior Software Engineer

KellyMitchell Group
Celebration, Florida, United StatesContract$55–$79Posted Aug 31, 2026

About the role

Job Summary

Our client, a leading entertainment and experiences organization, is seeking a Senior Software Engineer to join their team. This role will support a portfolio of mission-critical middleware, applications, scheduled jobs, and reporting solutions. The environment includes existing .NET applications alongside greenfield Java/Spring Boot services, with a key focus on supporting ongoing .NET applications and participating in .NET-to-Java/Spring Boot migration initiatives.

Contract Details

Contract length: 1-year contract

Location: Celebration, FL

Work Arrangement: Hybrid, 2 days per week onsite required

Core Responsibilities

Participate in the analysis, design, development, debugging, and modification of complex software applications and enhancements

Design, develop, test, and implement highly scalable software components, fixes, improvements, and new systems and applications

Build and support REST middleware integrating enterprise consumers

Maintain and enhance existing .NET applications, including bug fixes, enhancements, and production support

Plan and execute migrations of .NET services to Java/Spring Boot, including legacy code analysis, API parity, testing, and cutover support

Participate in the design, testing, deployment, and production support of mission-critical scheduled jobs and services

Collaborate with engineers, product partners, users, and cross-functional teams to define system requirements and deliver technical solutions

Required Skills/Experience (Must-Haves)

7+ years of related software engineering experience

Mastery of Java with experience in Spring and open-source technologies such as Tomcat, Nginx, and Elasticsearch

Experience with Angular and modern front-end development, including TypeScript, component-based architecture, and REST API integration

Experience with C# and .NET Framework and/or .NET Core, including the ability to read, debug, and refactor legacy .NET codebases while delivering equivalent Java/Spring implementations

Experience with the full application development lifecycle, including unit testing, code reviews, documentation, and Agile delivery

Experience with build and deployment technologies such as Jenkins, GitLab, Harness CI/CD, and Docker

Experience with AWS, Kubernetes, and Rancher, as well as monitoring and logging tools such as Grafana, AppDynamics, and Splunk

Preferred Skills/Experience (Nice-to-Haves)

Experience with strangler-fig or incremental migration patterns

Experience supporting parallel runs, feature flags, and phased application cutovers

Familiarity with event-driven and messaging architectures such as Kafka, SNS/SQS, JMS, or similar

Knowledge of API security best practices, including OAuth and JWT

Knowledge of distributed systems security, including TLS and secrets management

Key Competencies & Behaviors

Strong problem-solving and debugging skills

Strong communication skills and attention to detail

Effective collaboration with engineers, product partners, external partners, and contractors

Ability to work effectively within an Agile development environment

Ability to support complex, mission-critical applications and production environments

Work Environment

Location: Celebration, FL

Hybrid: Onsite 2 days per week, currently Tuesdays and Fridays, subject to change

Contract Duration: 1 year

Compensation & Benefits

Pay Range: The approximate pay range for this position is between $55.00 and $79.00. Please note that the pay range provided is a good faith estimate. Final compensation may vary based on factors including but not limited to background, knowledge, skills, and location. We comply with local wage minimums

Medical, Dental, & Vision Insurance Plans

Employee-Owned Profit Sharing (ESOP)

401K offered

About KellyMitchell

At KellyMitchell, our culture is world class. We’re movers and shakers! We don’t mind a bit of friendly competition, and we reward hard work with unlimited potential for growth. This is an exciting opportunity to join a company known for innovative solutions and unsurpassed customer service. We're passionate about helping companies solve their biggest IT staffing & project solutions challenges. As an employee-owned, women-led organization serving Fortune 500 companies nationwide, we deliver expert service at a moment's notice.

Marketing Disclosure

By applying for this job, you agree to receive calls, AI-generated calls, text messages, or emails from KellyMitchell and its affiliates, and contracted partners. Frequency varies for text messages. Message and data rates may apply. Carriers are not liable for delayed or undelivered messages. You can reply STOP to cancel and HELP for help. You can access our privacy policy at https://www.careers.kellymitchell.com/privacy-policy.

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Responsibilities

  • Participate in the analysis, design, development, debugging, and modification of complex software applications and enhancements
  • Design, develop, test, and implement highly scalable software components, fixes, improvements, and new systems and applications
  • Build and support REST middleware integrating enterprise consumers
  • Maintain and enhance existing .NET applications, including bug fixes, enhancements, and production support
  • Plan and execute migrations of .NET services to Java/Spring Boot, including legacy code analysis, API parity, testing, and cutover support
  • Participate in the design, testing, deployment, and production support of mission-critical scheduled jobs and services
  • Collaborate with engineers, product partners, users, and cross-functional teams to define system requirements and deliver technical solutions

Qualifications

  • 7+ years of related software engineering experience
  • Mastery of Java with experience in Spring and open-source technologies such as Tomcat, Nginx, and Elasticsearch
  • Experience with Angular and modern front-end development, including TypeScript, component-based architecture, and REST API integration
  • Experience with C# and .NET Framework and/or .NET Core, including the ability to read, debug, and refactor legacy .NET codebases while delivering equivalent Java/Spring implementations
  • Experience with the full application development lifecycle, including unit testing, code reviews, documentation, and Agile delivery
  • Experience with build and deployment technologies such as Jenkins, GitLab, Harness CI/CD, and Docker
  • Experience with AWS, Kubernetes, and Rancher, as well as monitoring and logging tools such as Grafana, AppDynamics, and Splunk

Benefits

  • Medical, Dental, & Vision Insurance Plans
  • Employee-Owned Profit Sharing (ESOP)
  • 401K offered

Skills mentioned

JavaSpring BootC#.NETAngularTypeScriptREST APIsDockerKubernetesAWS

About KellyMitchell Group

Connecting People with Opportunities + Clients with Success.® We’re KellyMitchell, a leading IT Staffing & Project Solutions partner — providing adaptive, scalable solutions focused on the top tech needs of the world’s leading organizations. Technology Solutions That Work for You We are dedicated to delivering technology solutions expertise — helping professionals achieve career excellence and companies achieve innovation goals. As an employee-owned, women-led organization, we have a strong commitment to fostering a diverse and inclusive workforce. Our work enriches careers and lives, drives business successes, and fuels technology innovation. Let’s work together! Clearly Rated's 2025 Best of Staffing® Client Award Clearly Rated's 2024 Best of Staffing® Client Award Clearly Rated's 2023 Best of Staffing® Client Award Clearly Rated's 2022 Best of Staffing® Client Award Clearly Rated's 2021 Best of Staffing® Client Award Clearly Rated's 2020 Best of Staffing® Client Award Clearly Rated's (previously Inavero) 2019 Best of Staffing® Client Award Inavero’s 2018 Best of Staffing® Client Award Inavero’s 2017 Best of Staffing® Client Award Inavero’s 2016 Best of Staffing® Client Award

IT Services and IT Consulting1,001-5,000 employeesSaint Louis, MO