Full Stack Developer (AI Native)

Pennymac (NYSE: PFSI) is a specialty financial services firm with a comprehensive mortgage platform and integrated business focused on the production and servicing of U.S. mortgage loans and the management of investments related to the U.S. mortgage market. 

At Pennymac, our people are the foundation of our success and at the heart of our dynamic work culture. Together, we work towards a unified goal of helping millions of Americans achieve aspirations of homeownership through the complete mortgage journey.

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.

Core Responsibilities

• Monorepo & Full-Stack Codebase Stewardship: 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.

• Domain Ownership (Payments & Rules Engine): 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.

• AI-Augmented Engineering: 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.

• Code Health & Complexity Management: 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.

• Mentorship & AI Standards: Mentor junior and mid-level engineers on AI-augmented coding workflows, prompting best practices, and secure AI-generated code validation.

• CI/CD, IaC & Automation: 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.

Required Technical Profile

• Education & Experience: Bachelor’s degree in Computer Science, engineering, or related field with 5+ years of professional software development experience (or equivalent practical experience).

• Enterprise Full-Stack Architecture: 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).

• AI-Native Tooling: 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.

• Monorepo & Complexity Management: 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.

• Payment/Rules Logic: Experience developing financial checkout systems, transactional rules engines, automated payment schedules, or complex business logic flows.

Preferred Skills:

• Cloud & IaC (Preferred): Exposure to cloud environments (AWS preferred), containerization, or Infrastructure as Code (Terraform, CloudFormation, or CDK).
• AI Innovation (Preferred): Familiarity with LLM integration, RAG pipelines, or vector databases.

As one of the top mortgage lenders in the country, Pennymac has helped over 4 million lifetime homeowners achieve and sustain their aspirations of home. Our vision is to be the most trusted partner for home. Together, 4,000 Pennymac team members across the country are guided by our core values: to be Accountable, Reliable and Ethical in all that we do. Pennymac is committed to conducting a business that makes positive contributions and promotes long-term sustainable growth and to fostering an equitable and inclusive environment, where all employees and customers feel valued, respected and supported. 

Benefits That Bring It Home: Whether you're looking for flexible benefits for today, setting up short-term goals for tomorrow, or planning for long-term success and retirement, Pennymac's benefits have you covered. Some key benefits include: 

• 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

To learn more about our benefits visit: https://pennymacnews.page.link/benefits

For residents with state required benefit information, additional information can be found at: https://www.pennymac.com/additional-benefits-information

Compensation: Individual salary may vary based on multiple factors including specific role, geographic location / market data, and skills and experience as defined below:

• Lower in range - Building skills and experience in the role
• Mid-range - Experience and skills align with proficiency in the role 
• Higher in range - Experience and skills add value above typical requirements of the role 

Some roles may be eligible for performance-based compensation and/or stock-based incentives awarded to employees based on company and individual performance.