Sr. Web Application Developer

We are seeking a highly experienced Senior Web Application Developer to serve as a technical leader, client liaison, and AI-enabled solutions engineer. This role requires a well-rounded full-stack background across modern web technologies, including but not limited to .NET/C#, JavaScript frameworks, cloud-native architectures, and emerging AI/ML integrations. The ideal candidate brings 8+ years of experience building scalable web applications, combined with hands-on experience incorporating AI/ML capabilities (e.g., generative AI, APIs, or data-driven models) into production systems. This individual will act as a trusted advisor to clients, shaping technical direction while leading engineering teams to deliver innovative, secure, and high-performing solutions. Primary Responsibilities Full-Stack Architecture & Technical Leadership Lead the architecture, design, and development of modern web applications across a diverse technology stack, including .NET/C#, Node.js, and front-end frameworks (React, Angular, Vue). Design and implement scalable, cloud-native solutions using microservices and serverless architectures. Establish and enforce engineering best practices, coding standards, and architectural patterns across teams. AI/ML Integration & Intelligent Solutions Design and implement AI-enabled application features, such as: Integration with LLMs and AI APIs (e.g., Azure OpenAI, AWS Bedrock, or similar platforms) Intelligent search, summarization, recommendation systems, or automation workflows Collaborate with stakeholders to identify opportunities where AI can enhance user experience, decision-making, or operational efficiency. Ensure responsible and secure use of AI technologies, including data privacy, governance, and model evaluation. Client Engagement & Technical Strategy Serve as a primary technical interface to clients, translating business needs into scalable technical solutions. Lead solutioning sessions, architecture discussions, and technical briefings with stakeholders. Provide strategic guidance on modern web technologies, cloud adoption, and AI integration. Build strong client relationships as a trusted technical advisor. Advanced Web Application & API Development Oversee development of secure, high-performance web applications and RESTful APIs. Ensure interoperability and cross-platform integration across systems. Drive best practices in API design, versioning, and performance optimization. Cloud & DevOps Enablement Architect and deploy applications in AWS and Azure, leveraging serverless and containerized services. Lead CI/CD pipeline implementation and DevSecOps practices. Optimize systems for scalability, reliability, and cost efficiency in cloud environments. Team Leadership & Mentorship Mentor developers across multiple technology stacks, not limited to .NET. Lead code reviews, architecture reviews, and technical decision-making. Foster a culture of innovation, continuous learning, and engineering excellence. Security, Performance & Quality Ensure applications meet modern security standards, including secure API design and cloud security best practices. Implement comprehensive testing strategies and performance monitoring. Continuously improve system resilience, scalability, and maintainability. UI/UX & Modern Web Practices Collaborate with UI/UX teams to deliver responsive, accessible, and user-centric applications. Drive adoption of modern front-end architecture and performance optimization techniques. Innovation & Continuous Improvement Stay current with emerging web and AI technologies, evaluating their applicability to client missions. Introduce new tools, frameworks, and AI capabilities to improve delivery and innovation. Basic Qualifications Must be able to obtain a Public Trust prior to starting (US Citizenship Required). Bachelor’s or Master’s degree in Computer Science, Information Technology, or related field (or equivalent experience). 8+ years of experience in full-stack web application development, including .NET/C# and modern JavaScript frameworks. Demonstrated experience working across multiple web technologies beyond .NET (e.g., Node.js, Python, or similar). Strong hands-on experience with T-SQL, including writing and optimizing SQL queries, stored procedures, triggers, functions, and other database objects. Demonstrated commitment to built-in quality, including developing reliable, maintainable, and well-tested solutions that meet performance, security, and coding standards. Ability to follow development best practices, conduct code reviews, troubleshoot issues, and ensure deliverables meet quality expectations throughout the development lifecycle. Hands-on experience integrating or developing AI/ML capabilities, such as: Working with AI APIs (Azure OpenAI, AWS Bedrock, etc.) Implementing data-driven or intelligent application features Strong experience with AWS and/or Azure cloud platforms, including serverless architectures. Deep understanding of web architecture, microservices, and RESTful API design. Experience with SQL and NoSQL databases. Proven ability to lead teams and engage directly with clients. Strong communication skills with the ability to bridge business needs and technical solutions. Knowledge of secure application development and cloud security practices. Preferred Qualifications Certifications in AWS, Azure, or AI/ML-related technologies. Experience building or integrating generative AI solutions in production environments. Familiarity with Python for AI/ML workflows. Experience with DevSecOps, CI/CD pipelines, and automation tools. Prior experience in client-facing technical leadership roles within complex or mission-driven environments. AppMod If you're looking for comfort, keep scrolling. At Leidos, we outthink, outbuild, and outpace the status quo — because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 — and moving faster than anyone else dares. Original Posting: June 16, 2026 For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above. Pay Range: Pay Range $107,900.00 - $195,050.00 The Leidos pay range for this job level is a general guideline onlyand not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.