Senior Frontend Engineer - Fintech Engineering (M/F/N)

In. Post Pay is building its own fintech platform from the ground up. It’s a large-scale, international initiative where engineers will have the opportunity to shape the architecture, build core fintech components, and create solutions designed to operate at In. Post’s scale. We’re building a lean, highly effective engineering organization in Poland, with AI-native engineering at its core .

We’re looking for strong engineers who are comfortable with agentic engineering, from experienced professionals building complex systems and engineering tooling to a new generation of engineers who have embraced AI-driven development from the start of their careers. → Hybrid working model: preferably 1 day per week in the Warsaw or Cracow office .

We're looking for a Senior Frontend Engineer to join our Fin. Tech Platform team and help us build seamless payment experiences for consumers and merchants. In this role, you'll own consumer-facing and merchant-facing payment journeys, driving frontend architecture, performance engineering, and product quality. You'll work across modern web technologies, contributing to highly scalable and secure payment solutions.

What will you work on? designing and implementing microfrontend architecture across payment products and services, owning performance engineering and continuously improving Core Web Vitals across customer-facing applications, participating in the full development lifecycle, from requirements and specification through testing and release, building integrations with backend services using GraphQL and REST APIs, implementing real-time user experiences using Server-Sent Events and similar technologies, developing secure payment-related user interfaces aligned with industry requirements and best practices, contributing to frontend tooling, developer experience, and modern engineering workflow.

This cooperation may be a strong match if you: have at least 5 years of experience building modern frontend applications, have hands-on experience with React, Vue, or Angular and TypeScript, have experience designing and implementing microfrontend architectures, have experience building and maintaining automated end-to-end tests using Playwright or similar frameworks, understand frontend performance optimisation, Core Web Vitals, profiling, and bundle analysis, have practical experience integrating REST and GraphQL APIs, are familiar with OAuth2, OIDC, JWT, feature flags, and progressive delivery approaches, actively use AI tools such as GitHub Copilot, ChatGPT, or Claude to improve development efficiency and quality, communicate in English at B2 level or higher.

Additional advantages: experience in payments, fintech, or e-commerce products, knowledge of PCI DSS requirements, CSP configuration, and secure browser-based architectures, experience with WCAG accessibility standards, backend development experience in Node.js, Java, Python, or C#, experience building embeddable widgets or SDKs.

What we offer

the opportunity to build products that sit at the heart of In. Post's growing financial services ecosystem, ownership of business-critical solutions operating at scale, a modern engineering environment focused on autonomy, accountability, and continuous learning, collaboration with highly experienced product, engineering, and business teams, access to cutting-edge technologies, event-driven architectures, and cloud-native solutions, opportunities to shape technical standards, mentor others, and influence platform evolution, full-time contract of employment.