Senior Software Engineer / TypeScript / React / Next / Node / Python

This is a full time, onsite Full Stack Engineering role with a fast-growing, SaaS company expanding its engineering presence in Arlington. The team builds software used by sports clubs, teams, and athletic organizations to manage websites, memberships, competitions, events, scheduling, and more. After years of success in Canada and rapid revenue growth, the company is launching a brand?new version of its platform for the US market using a modern stack. What makes this opportunity stand out is the blend of startup-style ownership with the stability of an established, profitable business. You’ll be part of the first US-based engineering team, working on a complete rebuild of their core SaaS product—no legacy code, no patchwork fixes, just greenfield development. If you enjoy fast?paced environments, solving real customer problems, and having a direct impact on product direction, this role offers significant growth, autonomy, and visibility. Required Skills & Experience • 4–7 years of professional software engineering experience • Strong experience with TypeScript, React, and Node.js • Strong Experience with Python • Ability to work pragmatically—shipping high quality features without over-engineering • Experience working in fast moving, startup-like environments • Strong communication skills and comfort collaborating cross?functionally • Must be able to work onsite 5 days/week in Arlington Desired Skills & Experience • Experience with Next.js • Experience with React Native and launching apps to both the Apple App Store and Google Play Store • Background in B2B SaaS or multi-tenant platforms • Experience building scheduling, event, or membership-based systems What You Will Be Doing Tech Breakdown • 60% TypeScript, React, React Native • 30% Node.js / Next.js backend development • 10% Python and supporting tooling Daily Responsibilities • 80% Hands-On Development • 10% Architecture & Technical Decision Making • 10% Team Collaboration, Product Input, and Iteration Applicants must be currently authorized to work in the US on a full time basis now and in the future. Posted By: Leonardo Tonaki