{"id":2112840,"url":"https://alion.io/job/square-one-resources-frontend-react-engineer","title":"Frontend React Engineer","company":{"id":3913592,"name":"Square One Resources","domain":"squareoneresources.com","url":"https://alion.io/company/square-one-resources","size_band":null,"is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":null,"truth_index":null},"role":"Frontend","role_family":"Frontend","seniority":"senior","employment_type":"contractor","work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["Warsaw, Poland"],"countries":["PL"],"hiring_countries":[],"hiring_countries_total":0,"salary":{"min":170,"max":200,"currency":"PLN","period":"hour","gross":null,"usd_annual":102000},"salary_estimate":null,"experience_years_min":5,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Agentic Workflows","optional":false},{"name":"AI Agents","optional":false},{"name":"Knowledge Graph","optional":false},{"name":"LLM","optional":false},{"name":"Next.js","optional":false},{"name":"RAG","optional":false},{"name":"React.js","optional":false},{"name":"Semantic Search","optional":false},{"name":"Semantic Search","optional":false},{"name":"TypeScript","optional":false},{"name":"Highcharts","optional":true},{"name":"JavaScript","optional":true},{"name":"Node JS","optional":true},{"name":"Python","optional":true}],"status":"live","first_seen_at":"2026-09-29T11:24:23Z","employer_posted_date":null,"last_verified_at":"2026-09-29T11:24:23Z","board_verified":false,"closed_at":null,"days_open":13,"trust":{"level":"not_scored","repost_count":null,"flags":[],"days_open":13},"description":"About the RoleOur client is a fast-growing technology company operating in the enterprise AI and software industry. The company is developing an AI-native platform that helps enterprises model complex business processes, workflows, policies, and operational knowledge, enabling AI agents to deliver reliable and scalable business outcomes.\nThe platform is already used by international enterprise customers and supports real production workloads at scale.\n\nWe are looking for a Senior Frontend React Engineer to join the team in Warsaw. This is a hands-on role focused on building business-critical user experiences for AI-powered products.\nYou will work with modern frontend technologies, complex application state, real-time AI interactions, and enterprise-grade functionality. You will have significant ownership over frontend architecture, product decisions, performance, and production quality.\nThe role is 100% office-based in Warsaw.\n What We OfferLong-term opportunity with a fast-growing enterprise AI product\n100% office-based work in Warsaw\nOpportunity to work on production AI products used by enterprise customers\nSignificant ownership over frontend architecture and product experiences\nModern React, Next.js, TypeScript and AI-focused technology stack\nOpportunity to work in an AI-native engineering environment\nCollaboration with experienced engineers and product teams\nA role with strong technical ownership and room for professional growth\nZakres obowiązków\nDesign and develop production-grade Next.js applications using React and TypeScript \nBuild complex user interfaces for AI-powered features, including streaming LLM responses, chat interfaces, semantic search, knowledge graphs, and agentic workflows \nWork with complex application state, real-time interactions, optimistic updates, and large-scale data synchronization \nDesign and maintain reusable component libraries and contribute to the company's design system \nEnsure high standards of accessibility, localization, cross-browser compatibility, security, and enterprise readiness \nOptimize frontend performance for high-load environments and large datasets \nMonitor and improve Core Web Vitals, bundle sizes, and overall application performance \nMake frontend architecture decisions and contribute to API and technical design discussions \nTake ownership of features throughout their lifecycle, from initial implementation through production monitoring and optimization \nParticipate in code reviews and contribute to engineering standards and best practices \nCollaborate closely with product and engineering teams to turn complex and ambiguous requirements into intuitive user experiences \nUse AI-assisted development tools and coding agents as part of the everyday engineering workflow \nWymagania\nRequirements5+ years of professional frontend engineering experience \n3+ years of hands-on experience with React and modern TypeScript \nStrong commercial experience with Next.js and production SSR applications \nGood understanding of Next.js App Router and Server Components \nPractical understanding of SSR, SSG, and CSR and the trade-offs between them \nExperience working with complex state management and real-time application behavior \nExperience building high-performance applications used under significant traffic or with large datasets \nStrong understanding of frontend performance optimization and Core Web Vitals \nExperience building enterprise applications where accessibility, localization, security, and compliance are important \nExperience working with AI/LLM-powered interfaces, such as streaming responses, chat applications, semantic search, RAG interfaces, or similar real-time AI functionality \nSecurity-conscious approach to frontend engineering, particularly when working with sensitive or enterprise data \nStrong product mindset and ability to identify UX problems and propose practical solutions \nAbility to work independently and take ownership of complex frontend areas \nStrong communication skills and ability to explain technical decisions and trade-offs clearly \nExperience using AI coding assistants or coding agents in day-to-day development \n Nice to HaveExperience with React Flow, Highcharts, or other advanced data visualization libraries \nExperience with vector search interfaces, RAG applications, or generative UI \nKnowledge of Node.js and/or Python, with the ability to understand backend code and participate in API design discussions \nExperience building or contributing to design systems or open-source component libraries \nExperience working with AI coding agents, orchestration tools, CLIs, logs, traces, or similar AI development workflows \n Tech stack\nReact\nAI\nNext.js\nTypeScript\nUser interface\nDesign System\nSecurity\nAPI\nSSR\nHighcharts\nData visualization\nUI\nNode.js\nPython\nROOM","description_format":"text","description_chars":4796,"description_truncated":false,"requirements":{"experience_years_min":5,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":null,"security_clearance":false,"languages":[]},"benefits":[],"hiring_locations":[],"hiring_excludes":[],"relocation_offered":false,"industries":[],"lifecycle":[{"event":"open","at":"2026-10-08T22:25:03Z"}],"visa":[],"liveness":{"score":75,"band":"hot","label":"Hiring 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