Application Developer II

McCarthy Holdings, Inc.; St. Louis (MO); On-site; USD 120,000 - 160,000; Full time

Benefits offered by this job

Employee ownership

Total Rewards benefits

Job summary

McCarthy Holdings, Inc. seeks an experienced Application Developer to build AI-enabled solutions on Palantir Foundry, focusing on UX and scalable, secure enterprise apps. You will collaborate with product owners, data engineers, and security teams to translate requirements into production-ready components.

The role emphasizes reusable components, API integrations, and adherence to DevSecOps practices while advancing McCarthy’s data-driven workflows and decision support.

Qualifications

• 5+ years of professional software development experience building enterprise applications.
• Experience delivering web applications with UI, API integrations, and security considerations.
• Familiarity with Palantir Foundry and AI-assisted development concepts is desirable.

Responsibilities

• Design and develop application solutions on Palantir Foundry, with primary responsibility for the application and user experience layers built on top of the Ontology.
• Build custom applications using OSDK, TypeScript, and React, integrating Ontology objects, relationships, Actions, and Functions to support structured data and unstructured content.
• Leverage Foundry capabilities, including Workshop, Functions, and AIP, to streamline operational workflows, enable AI-powered experiences, and support informed decision-making. Integrate applications with enterprise systems through REST APIs and supported event-driven patterns.
• Translate business requirements into secure, scalable, and maintainable application designs, applying established development patterns, creating reusable components, and incorporating usability, accessibility, and user feedback.
• Partner with data engineers and data architects to actively shape and develop a robust Ontology, ensuring its objects, relationships, properties, and Actions support application requirements and operational workflows.

Skills

.NET/C#

Java/Spring

Node.js/TypeScript

React

REST APIs

Git

CI/CD

Security best practices

Agile methodologies

Tools

Palantir Foundry

OSDK

Workshop

AIP

Git

CI/CD pipelines

Job description

McCarthy Holdings, Inc. (McCarthy), is the holding entity for McCarthy Building Companies, Inc., the oldest privately-held national construction company in America, and Castle Contracting. McCarthy provides the crucial business infrastructure for these entities and connects the day-to-day operations to ensure seamless operations across the business. Repeatedly honored as a great place to work and healthiest employer, McCarthy is a 100 percent employee-owned company.

At McCarthy, we are committed to sustaining a culture that delivers great experiences for everyone. This begins with developing high-performing individuals and teams through our award-winning learning and development programs, best-in-class Total Rewards benefits, and our inclusive culture aligned with our core values: Genuine. We, Not I. All In.

How do McCarthy partners define our culture?

• We Live Our Core Values: We do whatever it takes to deliver on our promises with honesty and integrity.
• We are Employee Owned: We are personally invested in building the things people need in our communities.
• We Feel Like a Family: We value genuine connections and help each other succeed in an inclusive environment.
• We are Builders: We respect the work we do and everyone who helps make it happen safely.

Position Summary

McCarthy is seeking a full-time Application Developer, who as part of the Engineering and Intelligence team, will play a crucial role in building business applications and user experiences on the Palantir Foundry platform, supporting existing systems, and driving innovation through modern DevSecOps practices.

The primary focus for this role is development on the Foundry platform: creating AI-enabled solutions that deliver intuitive user experiences, streamline operational workflows, support informed decision-making, and provide reusable application components that help McCarthy teams act on trusted data. The developer will work closely with product owners, data engineers, Foundry Ontology specialists, technology architects, and business stakeholders to translate user requirements into secure, maintainable, production-ready solutions.

Responsibilities

Solution Design and Development

• Design and develop application solutions on Palantir Foundry, with primary responsibility for the application and user experience layers built on top of the Ontology.
• Build custom applications using OSDK, TypeScript, and React, integrating Ontology objects, relationships, Actions, and Functions to support structured data and unstructured content.
• Leverage Foundry capabilities, including Workshop, Functions, and AIP, to streamline operational workflows, enable AI-powered experiences, and support informed decision-making. Integrate applications with enterprise systems through REST APIs and supported event-driven patterns.
• Translate business requirements into secure, scalable, and maintainable application designs, applying established development patterns, creating reusable components, and incorporating usability, accessibility, and user feedback.
• Partner with data engineers and data architects to actively shape and develop a robust Ontology, ensuring its objects, relationships, properties, and Actions support application requirements and operational workflows.

Quality Assurance and Delivery

• Develop and maintain automated tests, participate in code reviews, and validate application functionality, integrations, and AI-enabled features against defined acceptance criteria.
• Develop, test, and deploy solutions using strong CI/CD practices and Foundry’s branching, version control, and deployment capabilities to enable reliable releases.
• Apply Agile practices to plan and manage assigned work, communicate progress and dependencies, and deliver user stories iteratively.

Application Support and Continuous Improvement

• Monitor, troubleshoot, and optimize deployed Foundry applications, addressing defects, integration failures, and performance, usability, and reliability issues in collaboration with relevant teams.
• Implement and validate application fixes and enhancements using established testing, code review, and deployment practices.
• Identify opportunities to automate workflows, improve application performance, and enhance end-user experience.
• Stay current with Foundry capabilities and relevant development technologies, applying new knowledge to improve solution quality and delivery.

Security and Governance

• Develop applications that respect Foundry’s access controls, including roles, markings, and granular data permissions, and follow established security and governance standards.
• Apply secure coding practices to OSDK applications and integrations, including appropriate authentication, credential management, and handling of sensitive data.
• Test application behavior across user roles and permission levels, and collaborate with security and platform teams to address identified issues.

Collaboration and Knowledge Sharing

• Build strong partnerships with internal Digital Enterprise teams, business stakeholders, and product owners to understand McCarthy’s needs, clarify requirements, and define actionable user stories and acceptance criteria.
• Maintain application documentation, troubleshooting guides, and support procedures to enable effective maintenance and knowledge sharing.
• Share reusable components, development patterns, and lessons learned to strengthen team capabilities and promote consistent development practices.

Qualifications

• Minimum 5 years of professional software development experience building and supporting enterprise applications using a modern framework or stack, such as .NET/C#, Java/Spring, Ruby on Rails, or Node.js/TypeScript.
• Experience developing web applications, including user interfaces, application logic, and API integrations. Working knowledge of JavaScript or TypeScript and a modern front-end framework such as React, Angular, or Vue.
• Strong understanding of software engineering fundamentals, including application design, reusable components, version control, automated testing, debugging, and maintainable code.
• Experience building and consuming REST APIs, working with relational databases and SQL, and handling common data formats such as JSON.
• Practical experience with Git, CI/CD pipelines, and software delivery practices, including code reviews, automated testing, and deployment across development, test, and production environments.
• Working knowledge of secure application development, including authentication, authorization, secrets management, dependency security, and remediation of identified vulnerabilities.
• Understanding of the risks associated with AI-assisted development—including insecure code, exposure of sensitive information, and unverified dependencies—and how to mitigate them through code review, testing, and adherence to organizational policies for third-party code and dependencies.
• Demonstrated ability to learn new platforms and technologies quickly and apply them to deliver working solutions. Prior Palantir Foundry experience is not required; a strong aptitude and motivation to become proficient in Foundry development are essential.
• Experience working in an Agile environment, collaborating with product owners and technical teams to translate requirements into user stories and deliver solutions iteratively.
• Strong problem-solving, interpersonal, and communication skills, with a collaborative mindset and a commitment to continuous learning and improvement.

Preferred Skills

• Experience developing applications on Palantir Foundry using Workshop, the Ontology SDK (OSDK), Functions, or Actions.
• Proficiency in TypeScript and React, particularly for building interactive, data-driven applications.
• Experience using AI-assisted coding tools to improve development productivity while maintaining full responsibility for the correctness, maintainability, and security of delivered code.
• Familiarity with semantic data models or knowledge graphs and how entities, relationships, and business operations support application development.
• Experience incorporating AI capabilities into applications using Palantir AIP or comparable technologies, including integrating AI outputs into user workflows and evaluating their usefulness and reliability.
• Familiarity with cloud platforms such as AWS or Azure, containers, and event-driven integration patterns.

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