Lead Software Engineer- AI Augmented

Harnham; New York (NY); Hybrid; USD 150,000 - 210,000; Full time

Job summary

Harnham is seeking a deeply experienced frontend engineer with full-stack fluency to lead architectural decisions and champion high-quality engineering practices. The role emphasizes collaboration, direction, and sound judgment over quick baseline coding.

Hybrid work with the NYC office three days per week; commutable distance required. You will leverage AI agents to prototype, scaffold, and refactor while maintaining rigorous testing, correctness, and operational excellence.

Qualifications

• 10+ years of experience building production web applications.
• Expert-level proficiency with TypeScript, React, server-side rendered Next.js, and performant component-driven development.
• Ability to articulate complex technical trade-offs to stakeholders and translate product vision into high-fidelity technical direction.
• Demonstrated development of simple, reusable, changeable systems with refactors or scalable patterns.
• Preference for functional programming and immutability in modern frontend development.
• Advanced knowledge of the testing pyramid and automated tests as a safety net for rapid development.
• Proven technical leadership through mentorship, delegation, and high-quality code reviews.

Responsibilities

• Take Ownership: uphold a high bar for quality through design reviews, code reviews, test strategy, and production readiness.
• Collaborate cross-functionally with product, design, and engineers to shape solutions and tradeoffs.
• Architect for change: design and build full-stack, frontend-leaning systems that are small, composable, and adaptable.
• Improve performance and quality by enforcing architectural standards and catching subtle issues.
• Champion functional programming and immutability to simplify reasoning and debugging.
• Lead AI-assisted development: use AI agents for prototyping and refactoring, then harden with tests and validation.
• Raise quality through testing: build and maintain a robust automated test suite with fast CI feedback.

Skills

TypeScript

React

Next.js

Frontend architecture

Job description

We're looking for a deeply experienced frontend engineer with full-stack fluency who brings strong judgment and a thoughtful critical perspective. This role is not about producing baseline code quickly. Modern AI tools can do that. It's about collaboration, setting direction, making sound decisions, and driving technical quality. You will leverage AI agents as force multipliers while maintaining a high bar for correctness, maintainability, testability, and operational excellence.

Success here depends on engineering judgment-choosing the right solution, not just producing code.

Hybrid: NYC office 3 days/week (commutable distance required)

Key Responsibilities

• Take Ownership: You'll be accountable for upholding a high bar for quality through design reviews, code reviews, test strategy, and production readiness.
• Collaborate cross-functionally: Partner with product, design, and fellow engineers to shape solutions, clarify tradeoffs, and deliver reliably.
• Architect for change: Design and build full-stack, frontend-leaning systems that are intentionally small, composable, and resilient to evolving product requirements.
• Improve Performance & Quality: Enforce architectural and operational quality, catching subtle issues that are easy to miss in fast-moving, AI-assisted development.
• Champion Functional Patterns: Champion functional programming principles and immutability to reduce side effects and make systems simpler to reason through and debug.
• Lead AI-assisted development: You'll use AI assistants/agents for prototyping, scaffolding, refactoring, and exploratory development, then harden the result and rigorously validate through tests, reasoning, and edge-case review.
• Raise quality through testing: Build and maintain a strong automated test suite of unit, integration/contract, component/UI, and end-to-end coverage, with fast feedback loops in CI.

About You

• 10+ years of experience building production web applications
• Expert-level proficiency with TypeScript, strong experience with React, server-side rendered Next.js (or similar), and performant component-driven development (e.g. Reshaped UI)
• Ability to articulate complex technical trade-offs to stakeholders and translate product vision into high-fidelity technical direction.
• Demonstrated development of simple, reusable, changeable systems (with examples of refactors, platforming work, or scalable patterns).
• Preference for functional programming and a deep understanding of why immutability is critical in modern frontend development.
• Advanced knowledge of the testing pyramid and how to use automated tests as a safety net for rapid, iterative development.
• Proven technical leadership through mentorship, delegation, and high-quality code reviews.

AI-Assisted Engineering Expectations

• Hands-on experience with tools like Cursor (or equivalent AI-augmented IDEs) and all modern coding models.
• Practical understanding of where AI is strong vs. where it falls short, paired with sound discernment in its application.
• Ability to use AI agents to quickly project multiple approaches, compare tradeoffs, and converge on the best solution without shipping "AI-shaped" code.