Staff Fullstack Software Engineer, Core Performance

Role Description As a Staff Software Engineer at Dropbox, you'll be the singular technical owner of application performance across the Core org — the part of Dropbox that owns every consumer-facing surface: web, iOS, Android, and desktop. This is one of the company's most visible, cross-cutting technical challenges. Your mandate is to make Dropbox feel fast on every surface our customers use. You'll operate at the intersection of measurement, engineering, and product impact, owning ambiguous problems that span the entire stack and translate directly into business outcomes for hundreds of millions of users. There is no existing performance team at Dropbox — you'll define the discipline. You'll start with the web, profiling our highest-traffic React surfaces, producing flame graphs and heat maps, identifying the most valuable opportunities, and driving fixes through to shipped, measured wins. The web is your initial focus and the surface where you'll be most hands-on. From there, you'll lead the performance initiative across iOS, Android, and desktop by partnering with the internal platform experts who own those clients — coordinating strategy, transferring measurement practices, and driving the work, rather than building everything yourself. You'll also work across the Python and Go backend services that all of these surfaces depend on, since perceived performance rarely lives in one layer. Your influence will extend across Core Engineering. You'll define the measurement standards, regression-detection systems, and performance practices that other engineers rely on. You'll also be expected to use AI fluently in your own engineering work and to lead the optimization of AI-assisted workflows across Core, raising the productivity of every engineer around you. You'll bring clarity where there is uncertainty, raise the bar for engineering excellence through hands-on leadership, and shape how Dropbox thinks about performance for years to come. In return, you'll gain meaningful exposure to senior leadership, build foundational systems that unlock future product capabilities, and grow into an org-level technical strategist — helping advance Dropbox's mission to create a more enlightened way of working. Our Engineering Career Framework is viewable by anyone outside the company and describes what’s expected for our engineers at each of our career levels. Check out our blog post on this topic and more here . Responsibilities Drive performance improvement on the Dropbox web application as the first focus of the role — profiling React surfaces, producing flame graphs and heat maps, identifying the highest-impact opportunities, and shipping measurable improvements Lead the performance initiative across iOS, Android, and desktop by coordinating with internal platform experts who own those clients — setting strategy, defining measurement standards, and driving execution rather than implementing every fix personally Take performance improvements end-to-end: from measurement, to root-cause analysis, to shipped code changes, to validation in production telemetry Build and own the measurement, instrumentation, and regression-detection systems that engineering teams across Core depend on to ship performant code Write production code regularly — primarily JavaScript and React on the web, with backend work in Python and Go on the services those surfaces depend on Set engineering standards for performance work across Core Engineering, and mentor IC3 and IC4 engineers on profiling, measurement methodology, and performance-aware system design Apply AI tooling to performance work and lead the optimization of AI-assisted engineering workflows across Core, raising engineering throughput and shaping how Dropbox engineers use AI to ship better software faster Influence cross-org roadmaps and architectural decisions, partnering with engineering leaders, PMs, and designers to ensure performance is treated as a first-class product attribute Many teams at Dropbox run Services with on-call rotations, which entails being available for calls during both core and non-core business hours. If a team has an on-call rotation, all engineers on the team are expected to participate in the rotation as part of their employment. Applicants are encouraged to ask for more details of the rotations to which the applicant is applying. Requirements BS, MS, or PhD in Computer Science or a related technical field involving coding (e.g., physics or mathematics) or equivalent technical experience Minimum of 12 years of experience as a software engineer with 3+ years serving as a Senior. Demonstrated, hands-on experience driving measurable performance improvements in production web applications — including profiling JavaScript and React surfaces, identifying root causes through flame graphs, heat maps, traces, and RUM data, and shipping the fixes that moved the metric Demonstrated experience using AI tooling to accelerate performance work — applying LLMs and AI-assisted workflows to profiling analysis, root-cause investigation, refactoring, or shipping performance fixes Experience optimizing AI-assisted engineering workflows to improve the productivity of other engineers — selecting tools, defining patterns and guardrails, and measuring the impact on engineering throughput Production experience with modern backend services in Python or Go that support consumer-facing client surfaces Experience leading technical strategy on cross-cutting initiatives spanning multiple teams or surfaces, including writing design docs, defining architecture, and driving execution to measurable outcomes Has worked on a consumer user-facing product (versus a platform team or developer-facing API-based product), and shipped changes that moved customer-visible metrics Strong written and verbal communication skills, with a track record of influencing roadmaps and decisions outside their direct reporting line — including leading initiatives that depend on coordinating with platform owners they don't directly manage Preferred Qualifications Experience profiling and improving native iOS applications (Swift), including startup time, scroll performance, and memory behavior Experience profiling and improving native Android applications (Kotlin), including startup time, scroll performance, and memory behavior Experience profiling and improving desktop client applications, including startup, IPC, and resource usage Experience building or owning performance regression-detection systems integrated into CI/CD Experience with RUM telemetry pipelines, sampling strategy, and statistically rigorous comparison of performance data Track record of mentoring senior engineers (Senior and above) and raising the technical bar across an engineering organization Compensation US Zone 1 $248,200 — $335,800 USD US Zone 2 $223,400 — $302,200 USD US Zone 3 $198,600 — $268,600 USD