Senior Frontend Developer · Poland, Warsaw ·

Zexter; Warszawa; Hybrid; PLN 180,000 - 260,000; Full time

Benefits offered by this job

Fully remote

Competitive salary

International team

Strong Dev & Product teams

Clear career path

Modern tools

Job summary

ZEXTER is seeking a Senior Frontend Developer to build and scale our in-house platform. You will own frontend development, shaping architecture and delivering production-grade frontend features using React, Next.js and TypeScript.

Join a fast-growing international iGaming-focused team with modern tooling and minimal bureaucracy, fully remote work, and opportunities to influence product quality and career growth.

Qualifications

• 5+ years of commercial frontend development, including 3+ years with React, owning and supporting production apps under real user load.
• Strong TypeScript skills: strict mode, generics, utility types, discriminated unions, and fully typed API contracts without any.
• Advanced React 18/19 & Next.js knowledge: hooks, render cycle, Suspense, Server/Client Components, App Router, SSR/SSG/ISR, middleware, caching and routing.
• Experience with TanStack Query, including query management, invalidation, SSR prefetching/hydration, persistent cache and optimistic updates.
• Ability to design and evolve large-scale frontend architecture: clear module boundaries, layered structure, public APIs, and gradual legacy migration without blocking feature development.
• Strong focus on code quality and testing: Vitest/Jest, React Testing Library, Playwright/Cypress, ESLint/Prettier, code reviews and Core Web Vitals optimization.
• Experience with modern frontend infrastructure and operations: Git, CI/CD (GitHub Actions/GitLab CI), Sentry, Docker and Node.js deployments.
• Solid understanding of API communication and web security: REST, WebSocket, authentication/refresh flows, CORS, CSP, XSS, SSRF and secure BFF patterns.
• Experience working in a cross-functional product team with backend, design and QA, plus hands-on knowledge of Tailwind CSS, Zod and internationalization (next-intl or equivalent).
• English, Russian - B2 mandatory!

Responsibilities

• Develop and maintain scalable, high-performance frontend applications using React, Next.js and TypeScript.
• Design and implement robust frontend solutions, contributing to architecture decisions and improving existing systems.
• Build and deliver end-to-end product features, collaborating closely with backend developers, QA, design and product.
• Ensure code quality, performance and reliability through testing, code reviews, monitoring and continuous optimization.
• Contribute to development processes and frontend best practices, improving tooling, CI/CD, observability and overall engineering quality.

Skills

5+ years frontend

3+ years React

TypeScript

Next.js

TanStack Query

Tailwind CSS

Testing (Vitest/Jest)

Tools

Git

CI/CD

Sentry

Docker

Node.js deployments

pnpm workspaces

Job description

ZEXTER is a technology company developing its own full-stack platform for the digital entertainment and iGaming ecosystem. We build scalable technology solutions for operators, creators, and digital businesses, helping them launch, manage, scale and monetize their products more efficiently.

We are now looking for a Senior Frontend Developer to help us build and scale our in-house platform. This is a hands-on, product-focused role for someone with strong React and TypeScript expertise, solid experience building production-grade applications, and the ability to take ownership of frontend development in a growing product.

Responsibilities:

• Develop and maintain scalable, high-performance frontend applications using React, Next.js and TypeScript.

• Design and implement robust frontend solutions, contributing to architecture decisions and improving existing systems.

• Build and deliver end-to-end product features, collaborating closely with backend developers, QA, design and product.

• Ensure code quality, performance and reliability through testing, code reviews, monitoring and continuous optimization.

• Contribute to development processes and frontend best practices, improving tooling, CI/CD, observability and overall engineering quality.

Requirements:

• 5+ years of commercial frontend development, including3+ years with React, with experience owning and supporting production applications under real user load.

• StrongTypeScriptskills: strict mode, generics, utility types, discriminated unions, and fully typed API contracts withoutany.

• AdvancedReact 18/19 & Next.jsknowledge: hooks, render cycle, Suspense, Server/Client Components, App Router, SSR/SSG/ISR, middleware, caching and routing.

• Experience withTanStack Query, including query management, invalidation, SSR prefetching/hydration, persistent cache and optimistic updates.

• Ability todesign and evolve large-scale frontend architecture: clear module boundaries, layered structure, public APIs, and gradual legacy migration without blocking feature development.

• Strong focus oncode quality and testing: Vitest/Jest, React Testing Library, Playwright/Cypress, ESLint/Prettier, code reviews and Core Web Vitals optimization.

• Experience withmodern frontend infrastructure and operations: Git, CI/CD (GitHub Actions/GitLab CI), Sentry, Docker and Node.js deployments.

• Solid understanding ofAPI communication and web security: REST, WebSocket, authentication/refresh flows, CORS, CSP, XSS, SSRF and secure BFF patterns.

• Experience working in across-functional product teamwith backend, design and QA, plus hands-on knowledge ofTailwind CSS, Zod and internationalization (next-intl or equivalent).

• English, Russian - B2 mandatory!

Nice to have:

• Experience in iGaming, betting, fintech or other high-load domains with real-time data.

• Experience with admin panels and role-based access control.

• Node.js at the level of writing a BFF layer, proxies and small services.

• Monorepo experience: pnpm workspaces, Turborepo, Nx.

• Experience supporting legacy browsers and polyfills on a modern stack.

• Experience setting up observability: logging, tracing, dashboards.

What we offer:

• Fully remote work.

• Competitive salary.

• Opportunity to work in a fast-growing international iGaming company.

• Strong Development and Product teams.

• Minimal bureaucracy and the opportunity to directly influence product quality.

• Clear career path with the opportunity to grow.

• Interesting challenges and modern tools.