Demo

Applications Developer II

McCarthy Holdings, Inc.
St. Louis, MO Per Diem
POSTED ON 12/29/2025
AVAILABLE BEFORE 1/28/2026

Position Summary

McCarthy is seeking a full-time Application Developer located in St. Lous, MO who as part of the Enterprise Solutions and Analytics team, will play a crucial role in building our application and integration portfolio, supporting our existing systems and driving innovation following modern DevSecOps practices.

Key Responsibilities

Solution Design and Development

  • Design and develop custom applications using modern frameworks such as Ruby on Rails or Django, integrating them into McCarthy’s ecosystem of applications.
  • Design and develop integration solutions by applying best practices and standard patterns in data model design, data transfer and event-based processing. Leverage integration capabilities such as Rest APIs, message queues and remote process execution in developing solutions. Implement solutions that process both structured and unstructured data (images, videos, model files etc.).
  • Develop solutions for maximum reusability, using components available in enterprise applications and platforms. Promote modular approach in solution design and development. Maintain a robust integration application and integration environment to promote long-term flexibility and growth.
  • Support the procurement of new applications and platforms by evaluating technical capabilities and providing insight. 

Support and Administration

  • Provide technical support and guidance for efficient and effective resolution of issues. Respond to queries from application teams in a timely manner to reduce disruption to end users.

Security

  • Ensure integration and application solutions follow McCarthy’s security practices and guidelines.
  • Enforce input validation and output encoding, avoid hardcoded secrets and credentials, apply least privilege logic in API and service interactions, use strong modern cryptography, sanitize logs, and perform threat modeling early and regularly.
  • Adhere to and promote a shift-left security mindset for pipeline, secrets management and supply chain functions. 

Project Execution, Task Management

  • Follow best practices and support organizational effort in managing projects and tasks effectively. Demonstrate an agile mindset in planning and execution of tasks.

Continuous Learning and Improvement

  • Constantly seek to improve current solutions. Identify opportunities to improve performance, automate workflows and improve end-user experience.
  • Keep up with the latest on tools and platforms by attending vendor events and  leveraging learning opportunities.   

Internal Relationship Management

  • Develop strong partnerships with internal IT staff to ensure solutions address McCarthy’s needs effectively and requests are addressed in a timely and effective manner. Work closely with business system analysts and product owners in understanding requirements and building solutions that implement user stories effectively.

Qualifications

  • 5 years of application development experience on a modern stack (e.g., .NET 6 /C#, Node.js/TypeScript, Python, Ruby — Ruby on Rails/Sinatra/ActiveRecord) building RESTful services, event-driven components, and CI/CD-backed deployments; familiarity with containers and cloud services is a plus.
  • Experience with an enterprise iPaas (integration platform as a service) such as Boomi, Mulesoft or Snaplogic. Boomi experience would be preferable.  
  • Strong knowledge of database capabilities in building integration solutions, preferably on Oracle or SQL Server. Strong knowledge of SQL.  Solid understanding of data formats including JSON and XML.
  • Practical experience with secure file transfer (SFTP), key management, and PGP encryption in automated pipelines.
  • Working knowledge of DevSecOps practices and tools (DAST/SAST/SCA/secrets scanning) and severity-based remediation workflows in CI/CD.  Examples of tools include Checkmarx, OWASP, GitHub, Snyk, Terrasan and Terraform 
  • Knowledge of cloud platforms such as AWS, Azure and Microsoft Office 365. 
  • (Nice to have) Experience developing solutions on a data integration platform such as Palantir. Experience building applications using a low-code/no-code platform such as Microsoft PowerApps, Appian or QuickBase.
  • Experience working on projects using an Agile approach and the Scrum framework.
  • Constant learner with a passion for continuous growth and improvement.
  • Strong interpersonal and communication skills. Strong team player with a collaborative mindset.

 

McCarthy is proud to be an equal opportunity employer, including disability and protected veteran status.

Hourly Wage Estimation for Applications Developer II in St. Louis, MO
$41.00 to $52.00
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