Senior Full Stack JS Engineer

Role Description

If you’re looking to work on cutting-edge AI products, solve challenging problems, and be part of a fast-moving, high-talent team, you’ll love it here.

What You’ll Do:

• Lead, not just code — Seniors at NineTwoThree don’t just write great code—they lead projects, guide teams, and ensure execution quality.
• Connect the dots between product vision, technical feasibility, and business needs.
• Communicate options, trade-offs, costs, and timelines clearly to both our team and client.
• Lead projects end-to-end — from technical strategy to execution.
• Architect solutions and apply best practices for scalable, AI-powered products.
• Guide and mentor engineers, ensuring quality while delivering fast.
• Translate business needs into technical decisions, explaining trade-offs and timelines.
• Solve hard problems, direct implementation, and coordinate technical challenges with clients.

Qualifications

• True senior engineers — not just people with years of experience, but those who own solutions and drive execution.
• 5+ years of experience in Full Stack Software Development (React, Node.js, JavaScript, TypeScript, SQL).
• Strong knowledge of cloud platforms (AWS, Azure or GCP).
• Clear and thorough understanding of design patterns and software development best practices.
• Great communicators who can explain options, trade-offs, and technical details to clients and teams.
• Ability to break down complex problems into manageable tasks.
• Passion maintaining code style and standards and holding people accountable.
• Hands-on experience with microservices architecture.
• Experience with React.js, Node.js, JavaScript and Typescript (at least 5 years).
• RESTful API design and implementation.
• OAuth and single sign-on (SAML).
• Leaders who ensure execution quality, push teams forward, and keep projects on track.
• Strong communication and analytical skills.
• Relational and no-SQL databases — MySQL, PostgreSQL, Redis etc.
• Solid understanding of principles of JavaScript/TypeScript languages.
• Ability to freely express/present/discuss ideas in English (B2-C1 level).
• Flexibility with working hours to participate in meetings with Eastern USA.

Requirements

• Not for you? If you’re looking for a pure coding role where someone else makes the decisions, this isn’t it.

Benefits

• Annual paid vacation: 20 days-off per year during the first 3 years, further increasing to 25 days in later years.
• Paid sick leave, 10 national holidays and 2 company days-off.
• Well-being budget.
• Maternity/paternity leave.
• Accounting assistance.
• Reimbursement of expenses for professional development courses/certifications (up to 100% in agreement with the Manager).
• Hardware upon business needs.
• Strong positive engineering culture, a tightly-knit team of professionals with a good sense of humor.

Company Description

Join NineTwoThree AI Studio, a remote-first product design, engineering, and marketing studio, founded in 2012 and based in Boston. We build AI-powered web and mobile apps for big brands and fast-moving startups.

We’ve been growing 20% every year for the last 5 years, which means there’s plenty of room for career growth and promotions. Our work speaks for itself—some of our customers found us through five layers of referrals. That’s how much people appreciate what we do.

We focus on products with a positive impact in various domains from sports and health, to logistics and nuclear. But if you’re into gambling, adult entertainment, or crypto, we’re not your place.