Full Stack Engineer

Full Stack EngineerRemoteFull timeUnited StatesShare this job DescriptionClassWallet, a leading financial technology company in the United States serving agencies delegated responsibility to manage public funds, is seeking to hire a Full Stack Engineer to join our team.Agencies use ClassWallet to get public funds to the right people, and ensure the funds are used for the right purpose. ClassWallet's suite of products and services empowers agency administrators to dramatically increase efficiency of funds distribution and spend compliance, reduce programmatic costs, maximize the full potential impact of the program, and satisfy the needs and expectations of policymakers, constituents and public reporting. ClassWallet has processed over $6.7 Billion to date and serves public agencies across 39 states. In its 11+ years in operation, ClassWallet has completed over 12M transactions, funded 1.1M recipients, processed over 5M applications, and now serves 300+ state and local agency clients, supported by a team of 280+ full-time staff.The Company has developed an industry-defining digital wallet solution which has gained rapid traction among state and local agencies and school districts across America. ClassWallet ranks as the 61st fastest growing software company on the prestigious Inc. 5000 list of fastest-growing private companies and the 21st fastest growing financial technology company on the Deloitte Technology Fast 500 in 2023.While the Company delivers immense business value, the social impact of ClassWallet is a fabric that runs through its mission and corporate culture. As a result of ClassWallet’s innovation, public programs run with exponentially more efficiency and the impact and breadth of the programs for the individuals they serve is dramatically higher. This mission compliments the Company mission-based culture with focus on gratitude and work-life balance.About the RoleWe're modernizing a large, business-critical fintech platform. Our current system is a mature Node.js/Express + MongoDB backend (with RabbitMQ workers, batch jobs, and a reports service) paired with a tri-generational frontend — layers of Backbone/Marionette, legacy React class components, and a React + Redux + Material-UI app all coexisting in one codebase.We're looking for someone with the judgment to tell good patterns from bad ones — who can recognize where the legacy system went wrong, avoid repeating those mistakes in new work, and design scalable solutions that still have to live alongside a rigid, established system. You'll contribute to new NestJS services and Next.js UI, write tests, and ship changes that respect the constraints around you — using AI tooling (Claude Code, Copilot) as a force multiplier, not a crutch.What you'll doWork across the full stack — data model, API contract, UI, and production behavior — contributing to domains as they move onto the modern stack.Recognize bad legacy patterns and don't repeat them — read the existing Express/MongoDB and Backbone/React layers, understand where they fell short, and apply better practices in new development rather than carrying old habits forward.Design for scale within real constraints — build solutions that scale even when they have to integrate with a rigid legacy system that can't be changed wholesale.Build on the modern stack — NestJS modules (DI, guards, interceptors) and Next.js apps (App Router, server components, typed clients).Understand the strangler-fig approach — how legacy and new run side by side, behind feature flags, with zero data loss and no downtime — and contribute to it without disrupting it.Model relational data carefully — help move money-bearing/transactional data from documents into a normalized SQL schema with real constraints and safe migrations.Write tests as a default — unit, integration, E2E. The suite is what lets the team move fast safely.Spot and flag problems — the flaky test, the N+1, the missing index. Raise them clearly so they get prioritized, and...