Senior Software Engineer, Full-Stack

Company Overview Avantos AI is shaping the future of client relationship management by reimagining it through the lens of artificial intelligence. We are building the industry’s first AI-native operating system for financial services, transforming how firms onboard clients, deliver advice, and manage critical servicing workflows. Our platform consolidates fragmented data, automates complex processes, and embeds intelligent decision-making throughout every stage of the client lifecycle. Supported by Bessemer Ventures and MIT’s investment arm, our team comprises execution-focused, design-driven, product-centric founders and leaders from Wharton, MIT, top design programs, and unicorn SaaS companies. We move swiftly, tackle deep industry challenges, and build technology that empowers users to take charge of their workflows. If you thrive on client impact, innovative product design, and tackling complex problems, Avantos is the place for you. About the Role We’re looking for a Senior Full Stack Engineer with a strong frontend core — someone who thinks in React/Next.js first, but is fully capable of contributing at the backend layer using Golang when needed. Responsibilities Lead frontend architecture and experience design — owning React/Next.js interfaces end-to-end, with a focus on performance, UX, and scalability. Integrate cleanly with backend services and contribute to Golang APIs when needed — not just consume them. Collaborate tightly with product and design on experience decisions — not just implementation. Influence architecture, reliability, performance strategy, and engineering standards. Write high-quality, clean, well-structured code — and enforce that quality in reviews. Act as a technical force multiplier — mentoring, unblocking, and setting the technical bar. Minimum Qualifications 8+ years of engineering experience building production web applications. Expert-level frontend depth — React + Next.js mastery (streaming, modern rendering patterns, state strategy). Proven ability to design high-performance, scalable, modern frontend systems with clarity and intentionality. Solid backend competency — ideally Golang, but strong API design fluency is required. Deep understanding of performance, caching, hydration, code splitting, bundling, deploy strategy, DX/UX tradeoffs. Product and architecture instincts — you care about what should be built, not just how. Preferred Qualifications AI, fintech, or data-intensive product experience. Experience shaping design systems, frontend platforms, or reusable architecture patterns. Edge rendering, observability tooling, or event-driven architecture familiarity. Experience with relational databases (Postgres) What We Offer Competitive compensation + meaningful equity. Opportunity to define the technical foundation of a greenfield AI platform. A culture optimized for engineering excellence, focus, deep work, and ownership — not ticket factories.