Principal Full-Stack AI Engineer: Agentic Systems Leader

AppBuddy; Boston (MA); On-site; USD 200,000 - 220,000; Full time

Job summary

Validity is hiring a Principal Full Stack AI Engineer in Boston to ship AI-powered features and design robust systems. You will lead full-stack development across React, Next.js, and TypeScript, building agentic AI capabilities at scale.

You are a hands-on doer with a passion for quality, and you will mentor others while guiding architectural decisions. This role emphasizes rapid iteration, production-grade security, and collaboration across product teams.

Qualifications

• 10+ years of engineering experience shipping impactful products.
• Deep full-stack experience with React, Next.js, TypeScript, and PostgreSQL.
• 2+ years building agentic AI systems.
• Ability to work across multiple projects simultaneously leveraging agents to multiply output.
• Strong code review skills with judgment to maintain high quality in AI-assisted development.

Responsibilities

• Quickly build and ship full-stack features.
• Design and deploy agentic AI systems that solve real user problems.
• Work across multiple projects simultaneously, using agents to maintain velocity and context across concurrent workstreams.
• Perform rigorous code review – especially of AI-generated code – ensuring production-grade quality, security, and systems design.
• Set technical direction through architecture decisions, prototypes, and rapid experimentation.
• Help define and improve evaluation for agent-powered features.
• Move from idea to production-ready implementation at speed.
• Work closely with product managers, shipping, learning, and iterating.

Skills

React

Next.js

TypeScript

PostgreSQL

Agentic AI

Code review

Product sense

Systems design

Cross-project collaboration

Job description

Validity is hiring a Principal Full Stack AI Engineer in Boston to ship AI-powered features and design robust systems. You will lead full-stack development across React, Next.js, and TypeScript, building agentic AI capabilities at scale.

You are a hands-on doer with a passion for quality, and you will mentor others while guiding architectural decisions. This role emphasizes rapid iteration, production-grade security, and collaboration across product teams.