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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Senior Application Developer - **Company:** Essex - **Location:** Irvine, CA, United States - **Experience:** Expert - **Salary:** $123,000.0 - $153,000.0 - **Contract:** Permanent contract - **Skills:** JavaScript (Programming Language), .NET Framework, Application Programming Interfaces (APIs), Agile Methodology, Artificial Intelligence, Amazon Web Services, HTML5, Automation of Tests, C Sharp (Programming Language), Cascading Style Sheets (CSS), Cloud Engineering, Software Documentation, Code Generation, Software Quality, Code Review, Web Content Management Systems, Continuous Integration, Cursor, Software Design Patterns, DevOps, PostgreSQL, Microsoft SQL Server, Modular Design, MySQL, Software Architecture, Next.js, Responsive Web Design, Simple Object Access Protocol (SOAP), Software Engineering, Systems Integration, Strategies of Testing, TypeScript, Web Content Accessibility Guidelines, Web Applications, Web Services, Test-Driven Development (TDD), GitHub Copilot, ReactJS, Claude Code, Snowflake, AWS Lambda, AI Coding Agents, Backend, Agentic-AI, Git, Vue.js, Information Technology, Data Analytics, Virtual Agents, Api Design, Serverless Computing - **Published:** October 31, 2026 - **Apply:** https://essex.wd5.myworkdayjobs.com/essexcareers/job/Orange-County---North/Senior-Application-Developer_R9549 ## About the Role * Bachelor's degree in computer science, engineering or related discipline. * 8+ years of hands-on full stack web application development across the full lifecycle: requirements, design, build, test, deployment, and support. * Deep knowledge of software architecture and design patterns (e.g., separation of concerns, modular design, API design). * Strong automated testing skills (unit, integration, end-to-end, regression) and test-driven development. * Proficient in capturing workable requirements from end users and business stakeholders and writing specifications clear enough for an engineer, or an AI agent, to implement without ambiguity. * Strong code-review skills to assess AI-generated code for correctness, security, and maintainability. * Experience with AI coding tools (e.g., Claude Code, GitHub Copilot, Cursor), or a demonstrated eagerness to adopt them. * Experience building serverless applications (e.g., AWS Lambda, Vercel) with CI/CD and DevOps practices. * Strong knowledge of HTML5, CSS, JavaScript, and at least one backend language. * Preferred: .NET, C#, TypeScript, Next.js, React, Vue.js, and building AI/LLM-powered features. * Strong knowledge of SQL. Experience with Snowflake and PostgreSQL/MySQL/SQL Server. * Experience implementing responsive design and Web Content Accessibility Guidelines (WCAG) standards. * Proficient with Git and with integrating web services and APIs (REST and SOAP). * Experience developing in web content management frameworks. * Proficient in creating clear system design, process, and user documentation, including context files for AI agents. * Experience in agile software development, with a proven track record of on-time delivery. * Able to communicate technical concepts to non-technical associates and mentor junior developers., * Excellent written and verbal communication skills. Strong organizational and analytical skills. Ability to provide efficient, timely, reliable and courteous service to customers. Ability to effectively present information. * Ability to comprehend, analyze, and interpret documents. Ability to solve problems involving several options in situations. Requires intermediate analytical and quantitative skills. * A collaborative attitude, actively engaging with team members to share knowledge, resolve challenges, and foster a productive and inclusive work environment. * A quality-first, verify-don't-assume mindset and the curiosity to keep learning as AI evolves. * Decisions made with thorough knowledge of procedures and company policies to achieve set results and deadlines. Responsible for setting own project deadlines. Errors in judgment may cause short-term impact to co-workers and supervisor. * No formal supervisory responsibilities in this position. May provide informal assistance such as technical guidance and/or training to coworkers. May coordinate work and assign tasks. ## Description The Senior Application Developer designs, builds, and supports moderate to highly complex applications on a serverless, cloud-native architecture using an AI-first, agentic development workflow. AI coding agents such as Claude Code write most of our code; our developers own what makes it worth shipping: the architecture, the requirements and specifications, the tests, and the code review. This role suits an experienced full-stack engineer who wants to be at the forefront of how software is now built. The Essex Technology team is an all-inclusive group of passionate technologists dedicated to supporting each other while supporting and driving Essex to a tech-forward future. If you love solving problems, can appreciate well-architected systems, and enjoy making a big impact with your contributions, then this role is for you! WHAT YOU WILL DO: * Design and develop web applications for internal and external customers, using agentic AI tools to plan, implement, and iterate quickly while applying sound usability concepts. * Build on our serverless architecture (e.g., AWS, Vercel) across front-end UI, back-end APIs, and data, using low-code tools where they fit, to deliver scalable, secure, user-centric solutions. * Work with business stakeholders to shape requirements and translate them into clear functional specifications and acceptance criteria that drive AI-assisted implementation. * Define architecture, data models, and design patterns, and guide AI agents to implement within them. * Own test strategy: unit, integration, and regression suites that validate AI-generated code. * Take a lead role in code quality, security, and performance, critically reviewing AI-generated code. * Maintain, support, and modernize existing applications, using AI to analyze, document, and refactor legacy code. * Help lead architecture and design reviews, backlog refinement, and other scrum meetings. * Triage and resolve production issues, and deploy changes through automated CI/CD pipelines. * Contribute to technology best practices, including the secure, responsible use of AI tools. * Perform other tasks as assigned.