Senior Fullstack Engineer (AI)

Location: Boston-based, hybrid, 3 days per week in the office at Harvard Square, Cambridge, Massachusetts, US. Occasional travel to customer sites is required a few times per year.

Salary: $150,000–$200,000 annual base salary, depending on experience, plus equity and benefits.

Company

Proton builds an AI operating system for wholesale distribution, combining CRM, PIM, eCommerce AI, and order and quote entry AI in one platform.

What you will do

• Own end-to-end delivery of CRM platform features from ticket refinement through deployment, monitoring, and iteration.
• Use Claude Code and other agentic development tools to scope, build, review, test, and ship production-quality software.
• Work across TypeScript and Vue, Python, SQL, data modeling, infrastructure, and integrations.
• Design scalable schemas, queries, and APIs with attention to performance, reliability, correctness, and distributed-system failure modes.
• Collaborate with product managers, designers, and engineers in a squad model with two-week sprints, refinements, retrospectives, and code reviews.
• Work directly with customers to support onboarding, troubleshoot integrations, understand ERP configurations, and improve the platform.

Requirements

• 5+ years of software engineering experience with demonstrable production fullstack ownership.
• Strong software engineering fundamentals, including debugging, query-plan analysis, race-condition reasoning, and critical evaluation of AI-generated code.
• Daily hands-on experience with agentic development tools such as Claude Code, Cursor agent mode, Codex, or equivalent.
• Comfort working across Vue, Python, SQL, infrastructure, databases, and integrations.
• Experience designing efficient schemas and queries and reasoning about indexing, trade-offs, and distributed systems.
• Strong communication, ownership, judgment, and ability to work in a fast-moving startup environment.

Nice to have

• Experience integrating distribution ERPs such as Epicor Eclipse or P21.
• Experience with agentic products, MCP servers, tool-using agents, agent frameworks, evaluations, or system-level prompt and context engineering.
• Previous experience at an early-stage SaaS startup.

Culture & Benefits

• High-autonomy environment focused on end-to-end ownership and rapid delivery.
• Competitive salary, company stock options, and full benefits.
• Flexible schedule with high autonomy.
• Unlimited PTO and 10 company-paid holidays.
• 12 weeks of fully paid parental leave for primary and secondary parents, including adoption and fostering.
• Annual company-paid offsites.