Senior Full-Stack Developer (Next.js&TypeScript)

🏢 Summary: B2B contract for a Senior Software Engineer to develop and operate a JVM-based, event-driven platform remotely from Poland. The role provides end-to-end ownership of system design, delivery, production reliability, monitoring, and support, with a rate up to 140 zł/h net + VAT. 🗂️ Requirements: 5+ years of software engineering experience, End-to-end ownership of features and components, Java and Kotlin expertise, Event-driven systems experience, Distributed systems knowledge, Event-driven architecture and API gateway experience, PostgreSQL, data modelling, and query performance knowledge, Relational and non-relational database knowledge, Unit, integration, and end-to-end testing experience, Independent delivery, risk, sequencing, and dependency management, C4 model system design experience, DORA metrics, stability, SSDLC, velocity, and predictability familiarity, AI coding tools experience, Cloud platform familiarity, Docker and Kubernetes experience, Fluent Polish, Advanced English (B2/C1) 📃 Skills: Java, Kotlin, JVM, PostgreSQL, NoSQL, Docker, Kubernetes, C4, DORA, SSDLC, Claude, Codex, Cursor, Cloud 🏢 Description: Contract : B2B Rate : up to 140 zł/h net + VAT depending on skills and experience Location : Remote within Poland Start : ASAP Project : Development of a JVM-based, event-driven platform with end-to-end ownership of software design, delivery, and production reliability. Key Technologies/Areas Java, Kotlin, JVM Event-Driven and Distributed Systems PostgreSQL and NoSQL Docker, Kubernetes Cloud Platforms AI Coding Tools Project Overview We are looking for a Senior Software Engineer to join one of our client’s engineering teams. You will own features and components from refinement and system design through development, production deployment, monitoring, and post-release support. Responsibilities Own the end-to-end design and delivery of features and components. Create, maintain, and align system designs using the C4 model with the domain target architecture. Develop reliable, production-ready, and well-tested software using Java and Kotlin. Manage estimation, sequencing, delivery risks, and cross-team technical dependencies. Own monitoring, reliability, production support, and participation in on-call. Contribute to frontend development where required. Use AI coding tools as part of your daily workflow. Requirements 5+ years of professional software engineering experience , including proven ownership of features and components end to end. Solid foundation in the JVM , including Java and Kotlin . Production experience with event-driven systems. Good understanding of distributed systems, including idempotency, at-least-once vs exactly-once trade-offs, schema evolution, and partitioning. Experience with event-driven architecture, API gateways, and understanding when not to apply these patterns. Sound knowledge of relational and non-relational databases, including PostgreSQL , data modelling, and query performance. Proven experience delivering reliable software with unit, integration, and end-to-end testing. Ability to independently manage delivery, risks, sequencing, and cross-team dependencies. Experience owning system design at team scope using the C4 model. Familiarity with DORA metrics, stability, SSDLC compliance, velocity, and predictability. Experience using AI coding tools such as Claude Code, OpenAI Codex, opencode, Cursor, or similar. Familiarity with cloud service providers. Experience with Docker and Kubernetes . Fluency in Polish and advanced English (B2/C1) Nice to have Frontend experience with React, TypeScript, and Node.js. Hands-on production experience with Kafka. Experience with Microsoft Azure. Why join us? Rite NRG is a vibrant outsourcing technology company driven by the Right People. We are dedicated to empowering businesses through innovative software solutions. We focus on building strong partnerships and providing top-notch software solutions that drive real business growth. Our business model revolves around collaboration and delivering impactful results for our clients. Join us and be part of a team where great minds, Right Energy, and strong partnerships come together to shape the future of technology! Possibility of long-term cooperation on a full-time project engagement basis. Flexibility in organizing the provision of services, taking into account project requirements and agreed availability. Opportunity to contribute to technically advanced projects. Opportunity for international collaboration.

🏢 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: Join an early-stage product team to design and deliver scalable, high-volume backend systems using Node.js, TypeScript, and AWS. The role offers end-to-end ownership, influence over architecture and engineering practices, and mentoring responsibilities in a hybrid Kraków setup. 🗂️ Requirements: 5+ years of production software development with Node.js and TypeScript, Practical AWS knowledge, Distributed systems design knowledge, Scalability knowledge, Event-driven architecture experience, Automated testing experience, Independent problem-solving ability, English communication skills, Ability to work in an evolving, fast-paced environment 📃 Skills: Node.js, TypeScript, AWS, Lambda, ECS, S3, RDS, Jest, Vitest, Playwright 🏢 Description: Senior Backend Engineer: Node.js & AWS Location: Kraków, Poland Working model: Hybrid Contract: Employment agreement or B2B Build high-scale systems from the beginning We’re hiring an experienced backend engineer to join a growing international technology business as it expands its engineering presence in Kraków. This is an opportunity to help create a new product rather than inherit a finished roadmap. You’ll influence early technical decisions, build systems designed for demanding workloads, and take meaningful ownership from architecture through production. The company develops robust data infrastructure used by organizations operating in complex, high-stakes environments. Its technology processes large volumes of information and supports products where speed, availability, and accuracy genuinely matter. If you enjoy solving difficult engineering problems, making pragmatic architectural decisions, and seeing your work reach production, this role offers plenty of room to make an impact. What you’ll be doing Design and deliver scalable backend services with Node.js and TypeScript. Build APIs and asynchronous, event-driven workflows in AWS. Engineer reliable systems capable of supporting intensive, high-volume workloads. Own features throughout their lifecycle, from technical discovery and design to deployment and ongoing improvement. Help establish the architecture and engineering practices of a new product. Partner with product specialists and engineers across multiple disciplines. Support other developers through mentoring, thoughtful reviews, and knowledge sharing. Strengthen standards around testing, security, maintainability, and operational reliability. Respond constructively as requirements evolve and new technical challenges emerge. What we’re looking for At least five years of professional experience building production software with Node.js and TypeScript. Strong practical knowledge of AWS. Experience with services such as Lambda, ECS, S3, or RDS is especially relevant. A solid understanding of distributed system design, scalability, and event-driven architecture. Experience using modern automated testing tools such as Jest, Vitest, or Playwright. The confidence to investigate unfamiliar problems and move work forward independently. Clear English communication skills. Comfort working in an energetic environment where priorities and products continue to evolve. Additional experience we’d value You don’t need to bring everything on this list, but any of the following would be useful: Go development. Distributed platforms or messaging-based systems. Large language models or contemporary AI development tools. React. Relational and non-relational databases. Docker and Kubernetes. CI/CD pipelines and modern delivery practices. Why consider this opportunity? Join at an early stage and help shape a product’s technical direction. Work on challenging systems where performance and reliability are fundamental. Take genuine ownership without unnecessary layers of decision-making. Become part of a new engineering group in Kraków with room to influence how it develops. Collaborate in an international, English-speaking environment. Choose between an employment contract and a B2B arrangement. Work within a hybrid model in Kraków. Join a profitable, expanding business focused on sustainable long-term growth.

🏢 Summary: Oferta dla Senior Engineera do rozwoju i modernizacji platformy enterprise w kierunku cloud-native. Rola łączy projektowanie architektury, rozwój fullstack w Java i React oraz wdrażanie praktyk i integracji AI, w tym MCP. 🗂️ Requirements: Wieloletnie doświadczenie w inżynierii oprogramowania i rozwiązaniach enterprise, Bardzo dobra znajomość Java, Java EE i Jakarta EE, Praktyczne doświadczenie z React i TypeScript, Doświadczenie w projektowaniu architektury oprogramowania, Znajomość systemów rozproszonych i architektury usługowej, Doświadczenie z Azure, Znajomość CI/CD oraz Azure DevOps lub podobnych narzędzi, Doświadczenie z Docker, Doświadczenie w pracy z dużymi i złożonymi codebase’ami, Praktyczne wykorzystanie narzędzi wspieranych przez AI 📃 Skills: Java, JakartaEE, React, TypeScript, Azure, Docker, CI/CD, AzureDevOps, GitHubCopilot, MicrosoftCopilot, MCP 🏢 Description: 💰 Stawka: 105 PLN/h netto + VAT (B2B) 🌍 Tryb: 100% zdalnie 📅 Start: ASAP Poszukujemy Senior Engineera , który łączy doświadczenie w tworzeniu rozwiązań enterprise z kompetencjami architektonicznymi, Fullstack oraz zainteresowaniem AI. Rola obejmuje wpływ na architekturę produktu, standardy technologiczne i modernizację platformy. Technologie: Java / Jakarta EE, React, TypeScript, Azure, Docker, Kubernetes, CI/CD, Azure DevOps, GitHub Copilot, Microsoft Copilot, MCP Wymagania: wieloletnie doświadczenie w Software Engineering / rozwiązaniach enterprise , bardzo dobra znajomość Java / Java EE / Jakarta EE , praktyczne doświadczenie z React i TypeScript , doświadczenie w projektowaniu architektury oprogramowania, znajomość systemów rozproszonych i architektury usługowej , doświadczenie z Azure , znajomość CI/CD i Azure DevOps lub podobnych narzędzi, doświadczenie z Dockerem , doświadczenie w pracy z dużymi i złożonymi codebase'ami, praktyczne wykorzystanie narzędzi wspieranych przez AI . Nice to have: Kubernetes, modernizacja monolitycznych aplikacji enterprise, doświadczenie w sektorze finansowym / ERP , znajomość systemów legacy i C, doświadczenie w mentoringu Seniorów i Tech Leadów, doświadczenie w pracy w międzynarodowych, rozproszonych zespołach. Obowiązki: definiowanie i rozwój architektury aplikacji enterprise, podejmowanie decyzji technologicznych na poziomie wielu zespołów, modernizacja platformy w kierunku architektury cloud-native, projektowanie standardów i architektury front-endowej w React + TypeScript , rozwój praktyk związanych z wykorzystaniem AI w software development , udział w integracji rozwiązań AI i Model Context Protocol (MCP) , identyfikacja i redukcja długu technologicznego, mentoring inżynierów i Tech Leadów. Oferujemy: Stawkę do 105 PLN/h netto (B2B), Przelew w dogodnej formie Krótki 14-dniowy termin płatności faktury Bogaty pakiet usług prywatnej opieki medycznej Dostęp do platformy kafeteryjnej MyBenefit (umożliwiającej zamawianie kart Multisport, kart przedpłaconych do Ikea, Zalando, Notino i wielu innych)

🏢 Summary: Senior Software Engineer role focused on building AI-powered fintech software for receivables and debt collection. The position involves developing Node.js/NestJS backend services, scalable React applications, APIs, databases, and cloud-native Docker deployments. 🗂️ Requirements: 5+ years of professional software development experience, TypeScript proficiency, Node.js and NestJS proficiency, React application development experience, REST API development experience, GraphQL API development experience, MySQL or relational database experience, Docker and containerized application experience, Cloud platform familiarity, API communication library experience, Strong problem-solving and ownership mindset, Independent and collaborative team working ability, Excellent English communication skills 📃 Skills: TypeScript, Node.js, NestJS, React, REST, GraphQL, MySQL, Docker, Axios, GoogleCloud 🏢 Description: We are looking for a Senior Software Engineer (Node/React) to join a fast-growing European fintech company building AI-powered software that transforms how businesses manage receivables and debt collection. The platform automates financial workflows, streamlines collections, and integrates seamlessly with clients' systems, helping organizations improve cash flow through modern cloud-native technology and intelligent automation. You will play a key role in developing and maintaining backend services, building modern React applications, and contributing to cloud-native deployments. The ideal candidate enjoys solving technical challenges, takes ownership of features, and is passionate about delivering high-quality software while working with modern technologies and AI-powered solutions. Requirements 5+ years of professional software development experience Strong proficiency in TypeScript, Node.js (NestJS), and React Solid experience building modern React applications Experience developing and maintaining REST and GraphQL APIs Hands-on experience with MySQL or other relational databases Experience working with Docker and containerized applications Familiarity with Google Cloud Platform or other cloud platforms Experience using Axios or similar libraries for API communication Strong problem-solving skills with an ownership-driven mindset Ability to work independently while collaborating effectively within a team Excellent English communication skills Nice to Have Experience integrating AI services such as OpenAI APIs Experience with Tailwind CSS, Material UI (MUI), or similar UI frameworks Experience building cloud-native, serverless applications Familiarity with Agile development environments Startup experience Responsibilities Develop and maintain backend services using NestJS (Node.js) and TypeScript Build and enhance modern React applications with a focus on scalability and performance Develop and maintain REST and GraphQL APIs Integrate AI-powered capabilities into the product using modern AI services Design responsive user interfaces using Tailwind CSS, Material UI, and modern frontend technologies Manage application deployment using Docker in a cloud-native environment Design, optimize, and maintain MySQL databases and application data models Collaborate with cross-functional teams to deliver features from concept through production Participate in technical discussions, code reviews, and continuous improvement initiatives Take ownership of features while contributing to product quality, engineering best practices, and ongoing platform development

🏢 Summary: Senior .NET Developer role on a remote or flexible-hybrid contract, building cloud-native, data-intensive platforms for intelligent heating and hot-water management. The work focuses on event-driven services, scalable analytics, distributed event processing, cloud infrastructure, and user-facing applications for sustainable energy solutions. 🗂️ Requirements: 5+ years of commercial C#/.NET experience, Kubernetes experience, Basic Azure knowledge, Python experience, PostgreSQL experience, Event-driven architecture experience, Asynchronous messaging systems experience, English proficiency at B2 level or higher, Ability to work independently, Ability to work in a cross-functional engineering team 📃 Skills: C#, NET, Kubernetes, Azure, Python, PostgreSQL, Kafka, Iceberg, GreptimeDB, React, TypeScript, SpiceDB, ReBAC, ETL 🏢 Description: Salary: 1250 - 1500 PLN/MD + VAT Remote: 100% remote or flexible hybrid from Gdańsk / Kraków / Warszawa Why choose this offer? You will have the opportunity to develop and improve a software tool which helps provide customers all over the world with tailor-made heating and cooling solutions Your work will help create more sustainable, cost-efficient and environment friendly heating and cooling solutions The Jit community will bring you a nice time during regular integration meetings Project We are looking for experienced Senior .Net Developer who will be part of a team developing modern software solutions for the energy and smart building industry, focused on intelligent heating and hot water management systems. You will join a team building modern data-intensive and cloud-native software platforms focused on scalable analytics, distributed event processing, and real-time operational insights. You’ll work closely with backend, frontend, and platform engineers to design and develop event-driven services, cloud infrastructure, and user-facing applications. Expected competences and knowledge Strong experience with C# / .NET – min. 5 years of commercial experience Hands-on experience with Kubernetes and basic Azure cloud knowledge Practical experience with Python Strong practical experience with PostgreSQL Experience with event-driven architecture and asynchronous messaging systems English proficiency at a minimum B2 level Ability to work independently and as part of a cross-functional engineering team Nice to have : Experience with migration and platform transformation projects React / TypeScript skills Python skills focused on data engineering, analytics, ETL, and data processing Hands-on experience with Kafka Experience with modern data platform ecosystems Experience designing and developing cloud-native architectures Technologies you'll work with C# / .NET Python Apache Kafka Apache Iceberg PostgreSQL GreptimeDB / Time-series databases React, TypeScript Kubernetes Azure Cloud SpiceDB / ReBAC Event-driven microservices architecture Client – why choose this particular client from the Jit portfolio? Our Client engineers technologies that enable the world of tomorrow to do more with less. They meet the growing need for infrastructure, food supply, energy efficiency and climate-friendly solutions . Their products and services are used in areas such as refrigeration, air conditioning, heating, motor control and mobile machinery. They are also active in the field of renewable energy as well as district heating infrastructure for cities and urban communities. Their innovative engineering dates back to 1933 and today our Client is a world-leader , employing more than 27,000 employees and serving customers in more than 100 countries . They are still privately held by the founding family. About Jit Team The Human Factor of IT - it’s not just a slogan, it’s a philosophy. The foundation of Jit Team is people, which is why we prioritise you. We employ over 770 experienced experts , to whom we offer developmental projects, a wide range of benefits, and a proprietary professional development programme. Together with clients from around the world, we create innovative IT solutions delivered by highly specialised and efficient teams. Behind our maxim are also charitable and educational activities. We support schools, universities, and educational institutions by conducting workshops, running educational projects, sponsoring events, and donating learning equipment. We offer internships that help launch careers in IT. We support water rescuers and hospitals by providing the necessary equipment. We also support numerous charitable organisations helping people in need, children, and the elderly. We are a Polish company and we share what we have achieved over more than 15 years of activity. By supporting local initiatives, we contribute to the circulation of good energy.