Senior Frontend React Developer

🏢 Summary: Senior Frontend Engineer role building enterprise AI interfaces and production Next.js applications with complex state, real-time functionality, and scalable frontend architecture. The position is fully on-site in Warsaw city centre, five days per week, with responsibility for UI quality, performance, accessibility, and enterprise-grade features. 🗂️ Requirements: Work on-site in Warsaw city centre 5 days per week, 5+ years of frontend development experience, 3+ years of React and TypeScript experience, Production Next.js experience, App Router and Server Components expertise, SSR, SSG and CSR knowledge, Complex state-management experience, Real-time and multi-tenant application experience, AI or LLM interface experience, Frontend performance and Core Web Vitals expertise, Accessibility, localization and frontend security knowledge, Experience handling sensitive data, Experience using AI coding assistants 📃 Skills: React, TypeScript, Next.js, SSR, SSG, CSR, LLM, AI, CoreWebVitals, Accessibility, Localization, Security, Claude, Codex, Copilot 🏢 Description: Please note: This role requires working from our office in Warsaw city centre 5 days a week . This is a fully on-site position , and remote or hybrid work is not available . About us We believe that businesses are moving toward AI-powered work, and we are building a platform for this future. Many AI agents cannot handle complex business tasks. We created a platform that organizes company policies, workflows, and business knowledge into one AI data model. This helps AI agents make accurate decisions and deliver reliable results at scale. We already work with well-known enterprise customers such as Glovo, Nespresso, and HelloFresh. Our platform supports thousands of users and processes real production data. Customers trust us with important business knowledge because we provide a secure and reliable solution with SOC2, HIPAA-ready security practices, and strong integrations. Job description We are looking for a Senior Frontend Engineer who enjoys building high-quality user interfaces for enterprise AI products. In this role, you will design and build important frontend features, solve complex UI problems, and improve the user experience over time. You will take ownership of frontend architecture and help build production Next.js applications with complex state management, real-time AI features, and enterprise functionality. The position is based in Warsaw and requires working from the office. Responsibilities Design and build production Next.js applications that support complex state, high traffic, and real-time AI features. Create user interfaces for AI-powered tools, including streaming AI responses, semantic search, knowledge graphs, and AI agents. Build and improve our component library and design system to keep the user experience consistent, accessible, and reusable. Deliver enterprise features such as localization, accessibility, browser compatibility, and security. Monitor applications after release, improve performance, reduce bundle size, track Core Web Vitals, and help systems scale. Maintain high engineering standards through code reviews, testing, and mentoring other developers. Requirements More than 5 years of frontend development experience, including at least 3 years working with React and modern TypeScript. Strong experience building production applications with Next.js, including App Router, Server Components, and understanding SSR, SSG, and CSR. Experience managing complex application state, including real-time updates, optimistic UI, multi-tenant systems, and large amounts of data. Experience building AI or LLM-based interfaces such as chat applications, streaming responses, or semantic search. Strong knowledge of frontend performance and experience improving Core Web Vitals in large applications. Good understanding of accessibility, localization, security, and enterprise application standards. A security-focused approach and experience working with sensitive data. Strong product thinking and the ability to improve user experience without waiting for detailed designs. Experience using AI coding assistants as part of your daily development work. Good written and spoken communication skills and the ability to explain technical decisions clearly. Nice to have Experience with React Flow, Highcharts, or other data visualization libraries. Experience building vector search, RAG, generative AI, or semantic search interfaces. Basic knowledge of Node.js or Python to understand backend code and APIs. Experience contributing to design systems or open-source UI libraries. What we offer B2B contract and company stock options. MacBook Pro. Modern technology stack and the opportunity to contribute to open-source projects. An AI-focused development environment with tools such as Claude Code, OpenAI Codex, and GitHub Copilot. Our values Our leadership team has strong experience in AI, knowledge management, and enterprise SaaS. We have received more than $60 million in funding and have been recognized by Gartner as a Cool Vendor. Our work is guided by these values: Quality – We care about excellent work and high standards in everything we build. Momentum – We take initiative, share ideas, and keep moving forward. Accountability – We take responsibility for our work and give honest, respectful feedback. Hard work – We believe success comes from teamwork, dedication, and consistent effort. Learning agility – We stay curious, learn from mistakes, and continue improving. Adapt and thrive – We welcome change and see challenges as opportunities to grow. Win together – We work as one team, communicate openly, and support our shared goals.

🏢 Summary: Fullstack Engineer role focused on building and scaling SaaS products, internal tools, AI-driven workflows, and third-party integrations. The position combines React/Next.js frontend work with Node.js/NestJS backend development, async processing, and production LLM automation. 🗂️ Requirements: 2.5+ years of professional full-stack experience, React.js, Next.js, Node.js, External API integrations, AI development tools, SQL, PostgreSQL, Async processing, Queues, Background jobs, Reliable-system design, English fluency, Polish fluency 📃 Skills: React.js, Next.js, Node.js, NestJS, OpenAI, Claude, Cursor, SQL, PostgreSQL, REST, WebSockets, LavinMQ, BullMQ, Kafka, GitLab, AWS, Fly.io, Golang, Elixir, Rust, BigQuery, ClickHouse, gRPC 🏢 Description: At Web Impact, we’re more than just an email marketing agency and digital solutions provider. We build cutting-edge, socially impactful products that redefine how businesses operate in the digital world. We’re looking for a Fullstack Engineer who enjoys building complex systems, integrating external services, and leveraging AI tools to speed up development and automate workflows. If you’re excited about combining modern frontend development with AI-driven workflows and automation tools like Claude Code, Cursor, and LLM frameworks , this one is for you. What You’ll Do Develop and contribute to end-to-end features across SaaS products and internal tools, collaborating with senior engineers on architecture and implementation decisions. Build modern, high-performance frontends using Next.js and React.js Develop scalable backend services using Node.js / NestJS Design and integrate APIs (REST, WebSockets, external services) Build and maintain automation workflows and background jobs Work with async systems, queues, and event-driven architectures Integrate third-party services with real-world constraints (rate limits, retries, auth flows) Use AI tools to improve development speed, testing, and automation Collaborate directly with product, data, and leadership teams Build MVPs, proof-of-concepts, and new product ideas from scratch Rapidly validate business ideas through experimentation and iteration Help evolve successful prototypes into production-ready systems AI & Automation This role includes working with modern AI tooling and automation systems, with a strong focus on speed, ownership, and execution : Using tools like Claude Code, Cursor, and OpenAI SDK in daily development Building AI-driven workflows and integrations quickly and iteratively Automating repetitive processes (data handling, content, integrations) Applying LLMs in production with a pragmatic, results-first approach Taking ownership of problems - from idea to production Shipping fast, testing in real conditions, and iterating based on outcomes Being accountable for delivery - not just writing code, but making things work end-to-end Prioritizing execution over perfection - speed is key What We’re Looking For 2,5+ years of professional full-stack experience Strong frontend skills in React.js / Next.js Backend experience with Node.js (NestJS preferred) Experience integrating external APIs (auth, pagination, retries, rate limits) Hands-on experience with modern AI tools (OpenAI, Claude, Cursor, etc.) Good SQL skills (PostgreSQL preferred) Experience working with async processing, queues, and background jobs Understanding of building reliable systems (error handling, retries, observability) Strong communication skills and ability to work cross-functionally Fluent in English and Polish Nice to Have Experience with Rust (async, Tokio, Axum) Experience with Elixir (Phoenix LiveView, GenServer) Understanding of distributed systems and architectures Experience with multi-region deployments and geo-distributed infrastructure Experience building systems with high parallelism (a large number of workers processing jobs concurrently) Familiarity with distributed databases and data consistency trade-offs Experience with multi-tenancy architectures (tenant isolation, scaling strategies) Experience working with high-throughput event pipelines Our Tech Stack Frontend: Next.js, React.js Backend: Node.js, NestJS, Golang, Elixir, Rust Data: PostgreSQL, BigQuery, ClickHouse Infra: AWS, Fly.io , Google Cloud, DigitalOcean Queues & Workers: LavinMQ, BullMQ, Kafka CI/CD: GitLab CI AI/ML & Automation: Proprietary GenAI models, OpenAI, Claude, internal tooling Integrations: REST, gRPC, WebSockets, external APIs with rate limits Why Join Us? Work on high-scale SaaS systems processing hundreds of millions of events daily , with real-time pipelines and data-heavy workloads. Ownership from day one - influence architecture, technology choices, and product direction. Collaborate with world-class engineers, AI specialists, and PMs. Innovation-first culture - explore cutting-edge frameworks and architectures. Fast execution, minimal bureaucracy, no unnecessary meetings Opportunity to work with modern AI tooling in production Competitive senior-level compensation and career growth. Social impact - contribute to automation products that empower businesses and communities. Our Streamlined Hiring Process Initial call Technical deep dive with our team Decision