Full Stack Developer (AI Native)

Pennymac • Westlake Village, CA

7h • Onsite

About The Position

We are seeking a Full Stack Developer (AI-Native) to join our Digital Customer Experience (DCX) engineering team. In this role, you will lead the development, optimization, and maintenance of our customer-facing web platforms and APIs. You will act as the primary owner of the transactional payment processing engine, pricing/fee rules, and pipeline automation systems, leveraging cutting-edge AI coding assistants to drive immense engineering velocity, safety, and codebase elegance.

Requirements

• Bachelor’s degree in Computer Science, engineering, or related field with 5+ years of professional software development experience (or equivalent practical experience).
• Expert-level proficiency in ReactJS and modern front-end development patterns, alongside strong backend engineering skills in Node.js / TypeScript (scalable API design, database schema optimization, secure authentication).
• Proven track record of incorporating AI coding assistants (GitHub Copilot, Cursor, LLM-based CLI tooling) into your daily development workflow to dramatically increase delivery speed and code accuracy.
• Practical expertise managing multi-project workspaces (monorepos) to ensure strict separation of concerns, alongside a proven habit of decomposing complex/monolithic modules into lightweight custom hooks or utilities.
• Experience developing financial checkout systems, transactional rules engines, automated payment schedules, or complex business logic flows.

Nice To Haves

• Exposure to cloud environments (AWS preferred), containerization, or Infrastructure as Code (Terraform, CloudFormation, or CDK).
• Familiarity with LLM integration, RAG pipelines, or vector databases.

Responsibilities

• Maintain, scale, and optimize core frontend and backend monorepos containing React (React 19+) web platforms, TypeScript, and Node.js APIs. Ensure robust error handling, secure authentication flows, and high-performance execution.
• Design, refactor, and safeguard complex payment rules, fee calculation logic, and financial validation flows. Ensure all transactional workflows are highly resilient, compliant, and thoroughly covered by automated test suites.
• Embrace and champion AI coding tools (e.g., GitHub Copilot, Cursor, Claude Code) to accelerate development velocity, run complex codebase refactoring safely, and generate robust test coverage. Contribute to internal developer tools, AI agent integrations, or LLM-powered features.
• Actively monitor and refactor application files to maintain low cyclomatic complexity. Prevent technical debt buildup by decomposing monolithic codebases (such as routing and state controllers) into testable, modular units.
• Mentor junior and mid-level engineers on AI-augmented coding workflows, prompting best practices, and secure AI-generated code validation.
• Own and optimize delivery pipelines and developer workspaces. Configure automated formatting, continuous integration tests (such as cross-platform line endings), and work alongside DevOps utilizing Infrastructure as Code (Terraform, CDK, or CloudFormation) where applicable.

Benefits

• Comprehensive Medical, Dental, and Vision
• Paid Time Off Programs including vacation, holidays, illness, and parental leave
• Wellness Programs, Employee Recognition Programs, and onsite gyms and cafe style dining (select locations)
• Retirement benefits, life insurance, 401k match, and tuition reimbursement
• Philanthropy Programs including matching gifts, volunteer grants, charitable grants and corporate sponsorships

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level