Senior Software Engineer, Full Stack

About Reflex Reflex is building the infrastructure that powers modern retail labor. By 2030, Reflex will look like the largest retail workforce in the world without owning a single store. More than sixteen million Americans work in retail stores today, yet staffing remains reactive, inefficient, and costly for both retailers and workers. Retailers struggle with unreliable coverage and limited visibility into labor performance, while workers face unpredictable schedules and inconsistent income. Reflex addresses this problem through a real-time, on-demand retail labor marketplace that connects national retail brands with trained, high-performing workers. The platform enables stores to flex staffing dynamically as demand changes, while creating performance-driven opportunities for workers. We’re scaling fast with some of the most notable brands in retail and are live in over 1,200+ active stores in the US. This is a structurally complex, two-sided marketplace with real-world operational constraints. Reflex has demonstrated that the model works, with national retailers, growing marketplace liquidity, and rapid expansion. Backed by leading investors and operating at the Series A stage, the company is now focused on building durable systems that scale. Notable Investors: Indicator Ventures, Canaan Partners, Precursor Ventures, Sugar Capital, ATX Venture Partners, Clutch VC, Active Capital, Red Swan Ventures, Gaingels, and several industry thought leaders. The Role We're looking for a  Senior Software Engineer to help us build and evolve a large, complex platform at a fast pace. Reflex has been live and growing since 2021, so you'd be joining an established system rather than starting from scratch. That means a Django backend, a relational data model, a set of React web applications, a mobile app that ships frequently, and a background processing layer behind it all. It's a genuinely interesting system to work in, and like any platform that has grown quickly, it is complicated and provides plenty of opportunity to learn new systems, infrastructure and languages. A meaningful part of this role is building new compelling features that exceed expectations for Retailers and Reflexers while helping us evolve to a scalable, reliable solution. Those two goals pull against each other constantly, and we're looking for someone with the judgment to navigate that and the communication skills to bring the team along. This is a true full-stack generalist role with a lean toward UI and software design. One week you might be designing the component architecture behind a new worker journey, and the next you might be improving the performance of a slow API query or building the telemetry that shows us why a mobile screen feels slow. You'll work closely with product and design to turn ambiguous problems into simple, scalable solutions. We move quickly. Releases go out weekly, and mobile more often than that. If you enjoy a broad surface area, a lot of autonomy, and a short path between making a decision and seeing its impact, you'll like it here. What You'll Own Build and ship across the full stack  — front-end experiences, backend services and APIs, infrastructure, and integrations. Own product areas end to end , from architecture and implementation through deployment, iteration, and ongoing maintenance. Lead our component design.  Our shared UI package is the design system behind our web applications. You'll shape its architecture, its conventions, and the standard for what belongs in it, so teams can build consistently and move faster. Own telemetry across mobile and web.  We have tracing, error monitoring, analytics, and feature flagging in place across the stack. What we'd like to add is a clearer picture of what we measure, how we alert on it, and how quickly an engineer can tell what's happening and who it affects. This is yours to build. Lead meaningful refactoring  of a large, long-lived codebase while we keep shipping. Incremental migrations and delivering improvements in slices are core to how we work. Help us make good calls on technical debt , and document the reasoning so it's clear to whoever picks it up next. Champion quality engineering practices.  We'd value someone who speaks up when a small change would create an outsized maintenance burden, or would pull us away from the design patterns we've agreed on. Balancing that against delivery is a real and valued part of this role. Design and evolve  backend services, APIs, data models, and integrations. Keep the platform fast and reliable at scale , with a focus on performance, observability, and developer experience across a system serving more than a million requests a day. Deploy and version our mobile product  multiple times a week. Raise the technical bar  through thoughtful code review, engineering standards, and mentorship. Debug and solve problems  across application, infrastructure, and data layers. Help shape our technical direction  and engineering culture as the team grows. The Work We're a small team with a wide surface area. Over a year here, you'd likely touch most of this: Product engineering  — worker- and retailer-facing experiences in TypeScript and React, from first sketch through production. Design systems  — a shared component library used across our web applications, and the conventions that keep them coherent as the team grows. Backend and API design  — Python and Django services, data modeling, and the APIs our web and mobile clients depend on. Mobile  — a mobile app with a frequent release cadence and real product surface of its own. Data  — relational data at meaningful volume, plus the pipelines and models behind our internal reporting. Platform and infrastructure  — cloud infrastructure, CI/CD, and the deployment tooling that gets our work in front of users. Performance and reliability  — profiling, caching, and query work on a system serving more than