Senior Software Engineer, Web Performance

Job Description

AlphaSense is seeking a Senior/Staff Software Engineer to join its Web Infra team in Helsinki. This role focuses on enhancing the performance, scalability, and reliability of AlphaSense's frontend platform, which is built on React with a microfrontend architecture. The engineer will collaborate with product teams to identify performance bottlenecks, guide technical decisions, and implement strategies for faster user experiences.Responsibilities:

• Own and improve performance across the existing React based microfrontend architecture and product features
• Identify and codify React performance best practices, architectural trade offs, and code level improvements in the existing codebase.
• Establish and enforce performance targets for LCP, INP, FCP etc. and integrate tools like Lighthouse CI, Sentry Performance into CI/CD pipelines.
• Collaborate with product teams to analyze the performance patterns and practices impact of new features and help define fast-by-default development patterns.
• Partner with designers and product managers to define performance SLAs and ensure UX remains performant under real world conditions.
• Profile and diagnose runtime issues (e.g. slow interactions, re-renders, memory leaks) using Chrome DevTools, React Profiler, and telemetry.
• Work across teams to reduce bundle sizes, optimize resource loading (code splitting, preloading, lazy loading), and optimize caching strategy.

Requirements:

• Advanced knowledge of React performance tuning: avoiding unnecessary re-renders, memoization etc.
• Hands-on experience working with large scale frontend codebases, microfrontend architecture, and Webpack module federation.
• Deep understanding of the browser rendering lifecycle, JavaScript execution, layout/paint/composite phases, and async scheduling.
• Strong background in profiling, debugging, and optimizing existing codebases at scale.
• Proficiency in modern JavaScript, TypeScript, and modern build tools like Webpack, Rollup, Vite, etc.
• Familiarity with monitoring and observability stacks like Sentry, or custom telemetry pipelines.
• Experience identifying performance regressions early and building guardrails via CI, testing, and automation.

What AlphaSense Offers:

• Interesting career opportunities and training
• Relocation support
• Flexible working arrangements with a hybrid model (office visits once a week)
• Private healthcare services
• Vacation days
• Access to gym room, gaming room, free parking
• Mobile phone, lunch benefit, mobile plan, home internet, remote work equipment