Fullstack Developer (Python + React) – US Time Overlap (12–18 CET)

🏢 Summary: Full-stack Developer role in an international product team building a scalable, data-driven platform supporting complex global decision-making processes. The position focuses on active product development with real ownership, combining Python-based backend and React frontend in a collaborative Agile environment. Requires daily overlap with US time zones. 🗂️ Requirements: 5+ years of experience as Fullstack Developer, Strong experience with Python, Experience with Django or Flask, Solid experience with React, Understanding of REST APIs, Knowledge of web application architecture, Experience with relational databases, Experience with PostgreSQL, Familiarity with Docker, Experience with CI/CD, Very good English, Availability for US time overlap (12:00–18:00 CET) 📃 Skills: Python, Django, Flask, React, REST, PostgreSQL, Docker, CI/CD, AWS, ECS, ECR, S3, TypeScript 🏢 Description: Holisticon Connect is a division within NEXER GROUP – a custom software development company. We started in Poland in 2017 and are now a team of over 140 people. We have the opportunity to work with world-renowned brands from Scandinavia, the UK, and Western Europe. Our goal is to grow stronger, in competence rather than in numbers. If you like what we do, check out our offer, maybe we will have the pleasure of meeting you! 😊 We are looking for a Full-stack Developer , who will join an international product-driven team working on a cutting-edge platform combining advanced data, scalable systems, and modern web technologies. The product supports complex decision-making processes and operates at a global scale. The team works in a highly collaborative environment with engineers and stakeholders based in the US and Europe. This is not a maintenance project – it’s active product development with real ownership and engineering influence. Because of the distributed setup, daily overlap with US time zones (12:00–18:00 CET) is required. We offer a competitive remuneration: B2B: 140 – 160 PLN net/hour + VAT Your responsibilities: Designing and developing fullstack web applications (backend + frontend); Building new features and improving existing functionalities; Writing clean, scalable, and testable code; Collaborating closely with Product, Design, and other Engineers; Participating in code reviews and technical discussions; Contributing to architecture decisions and continuous improvements; Working in an Agile/Scrum environment. You might be the perfect match if you are/have: 5+ years of experience as a Fullstack Developer; Strong experience with Python (Django or Flask preferred); Solid frontend experience with React; Good understanding of REST APIs and web application architecture; Experience with relational databases (PostgreSQL preferred); Familiarity with Docker and CI/CD practices; Very good English (daily communication with international team); Availability to work with required US overlap (12:00–18:00 CET). Moreover, we appreciate skills in these areas: Experience with AWS (ECS, ECR, S3 or similar services); Knowledge of TypeScript; Experience working in product-oriented teams; Exposure to data-heavy or performance-sensitive systems. By joining us, you gain the following: Opportunity to work on exciting, international projects in cutting-edge industries like Automotive, Biotech, IoT; Possibility to develop in cloud technologies; Becoming part of a team that believes that the next step to a promising future is to put your heart into it and make it happen; Respect for your private life, so you don't have to work overtime or on weekends; Team Events budget to socialize outside of work; Company Events to celebrate smaller and bigger successes (Summer Party, Programmer's Day, and trips abroad – so far we've been in South Africa, Are, and Barcelona). Perks and benefits: Fully remote work or in our office in Wrocław; Benefits such as Luxmed , Multisport , and life insurance in Nationale Nederlanden ; Attractive referral system (9,5k for senior, 6k for mid, 2,5k for junior); Personal Training Budget with additional paid hours; Passion Day - an extra day off for your hobby to spend as you please; Flexible working hours with no micro-management approach. Our core hours are 9-15, the rest of the working time is up to you; We provide high-quality work equipment + 2 additional monitors and accessories. If you apply for this position and match our expectations, then: 1) You will be invited to an HR Screening with our IT Recruiter. 2) You will have a technical interview. 3) You will meet with a client. Submit your application online in one easy step! Apply now!

🏢 Summary: Fullstack Engineer role focused on building secure, scalable applications to support genomic data science and AI-driven insights in healthcare. The position involves developing and deploying cloud-based solutions using modern TypeScript and Python stacks in AWS. B2B contract with competitive hourly rate and fully remote work option. 🗂️ Requirements: Expertise in TypeScript with React and Node.js, Expertise in Python with FastAPI, Experience building and deploying applications in AWS, Experience with AWS CDK, ECS, ALB, EC2, Strong knowledge of Docker and containerisation, Experience designing and securing APIs, Experience with LangGraph or agentic AI systems, Strong knowledge of SQL and NoSQL databases, Experience with PostgreSQL or similar databases, Experience logging, monitoring and debugging production systems, Ability to work in Unix/Linux environments, Bash scripting skills, Fluent English (C1), Location in Poland (min. 5 years), Availability up to one month 📃 Skills: TypeScript, React, Node.js, Python, FastAPI, AWS, CDK, ECS, ALB, EC2, Docker, SQL, PostgreSQL, NoSQL, LangGraph, Bash, Linux, Unix, REST, Monitoring, Logging, Debugging 🏢 Description: Holisticon Connect is a division within NEXER GROUP - a custom software development company. We started in Poland in 2017 and are now a team of over 140 people. We have the opportunity to work with world-renowned brands from Scandinavia, the UK, and Western Europe. Our goal is to grow stronger, in competence rather than in numbers. If you like what we do, check out our offer, maybe we will have the pleasure of meeting you! 😊 We are looking for a Fullstack Engineer to join a team that is expanding its genomic data science capabilities to explore data from multiple sources. The goal is to gain insights into the genomic drivers of common diseases and support the identification of novel therapeutic targets. We offer a B2B contract: 140 – 160 PLN net/hour + VAT You might be the perfect match if you are/have: ✅ Technical skills: Expertise in TypeScript (JavaScript) - React & Node.js; Expertise in Python (& FastAPI); Experience building and deploying secure and scalable apps in AWS (e.g., AWS CDK, ECS, ALB, EC2); Strong understanding of containerisation (+ deployment) - Docker ; Experience designing and securing APIs ; Experience with LangGraph and/or building agentic AI systems ; Strong knowledge of databases – SQL (PostgreSQL or similar) and NoSQL ; Experience logging, monitoring, and debugging production systems; Ability to work in Unix/Linux environments and with Bash scripting. ✅ Soft skills and others: Robust software development best practices and documentation; Proactive and self-driven, able to identify opportunities and suggest tasks rather than waiting for assignments; Strong team player , comfortable collaborating and contributing in group settings; Strong communication skills; Positive mindset and constructive approach to challenges; Initiative-taker who is not afraid to lead or push ideas forward and deliver in a fast-paced environment; Eager to learn, grow, and continuously develop new skills; Fluent English (C1) for effective collaboration in an international environment; Location in Poland (at least 5 years), enabling smooth cooperation and occasional in-person team meetings; Availability up to one month . Moreover, we appreciate skills in these areas: 5+ years of experience in a similar senior role; Strong product mindset; Familiarity with CI/CD pipelines; Familiarity with Domino Data Lab; AWS CloudFormation, CloudFormation, Lambda; Nginx; Other Python frameworks like Flask; Experience with testing frameworks/tools (e.g. Playwright, Jest); Interest in Life Sciences and Drug Discovery. By joining us, you gain the following: Opportunity to work on exciting, international projects in cutting-edge industries like Automotive, Biotech, IoT; Possibility to develop in cloud technologies; Becoming part of a team that believes that the next step to a promising future is to put your heart into it and make it happen; Respect for your private life so you don't have to work overtime or on weekends; Team Events budget to socialize outside of work; Company Events to celebrate smaller and bigger successes (Summer Party, Programmer's Day, and trips abroad – so far we've been in South Africa, Are, and Barcelona). Perks and benefits: Fully remote work or in our office in Wrocław; Benefits such as Luxmed , Multisport , and life insurance in Nationale Nederlanden ; Attractive referral system (9,5k for senior, 6k for mid, 2,5k for junior); Personal Training Budget with additional paid hours; Passion Day - an extra day off for your hobby to spend as you please; Flexible working hours with no micro-management approach. Our core hours are 9-15, the rest of the working time is up to you; We provide high-quality work equipment + 2 additional monitors and accessories. If you apply for this position and match our expectations, then: 1) You will be invited to an HR Screening with our IT Recruiter. 2) You will have a technical interview. 3) You will meet with a client. Submit your application online in one easy step! Apply now! You will earn: B2B: 140 – 160 PLN net/hour + VAT

🏢 Summary: Fullstack Engineer role focused on building secure, scalable applications to support genomic data science and AI-driven insights for disease research and therapeutic target identification. The position involves developing and deploying cloud-based systems using modern TypeScript and Python stacks in AWS environments. B2B contract with fully remote work and collaboration in an international team. 🗂️ Requirements: Expertise in TypeScript and React, Expertise in Node.js, Expertise in Python and FastAPI, Experience building and deploying applications in AWS, Experience with containerization using Docker, Experience designing and securing APIs, Experience with SQL and NoSQL databases, Experience with logging, monitoring, and debugging production systems, Ability to work in Unix/Linux environments, Bash scripting skills, Fluent English (C1), Location in Poland 📃 Skills: TypeScript, JavaScript, React, Node.js, Python, FastAPI, AWS, CDK, ECS, ALB, EC2, Docker, SQL, PostgreSQL, NoSQL, LangGraph, Unix, Linux, Bash, CloudFormation, Lambda, Nginx, Flask, Playwright, Jest 🏢 Description: Holisticon Connect is a division within NEXER GROUP - a custom software development company. We started in Poland in 2017 and are now a team of over 140 people. We have the opportunity to work with world-renowned brands from Scandinavia, the UK, and Western Europe. Our goal is to grow stronger, in competence rather than in numbers. If you like what we do, check out our offer, maybe we will have the pleasure of meeting you! 😊 We are looking for a Fullstack Engineer to join a team that is expanding its genomic data science capabilities to explore data from multiple sources. The goal is to gain insights into the genomic drivers of common diseases and support the identification of novel therapeutic targets. We offer a B2B contract: 140 – 160 PLN net/hour + VAT You might be the perfect match if you are/have: ✅ Technical skills: Expertise in TypeScript (JavaScript) - React & Node.js; Expertise in Python (& FastAPI); Experience building and deploying secure and scalable apps in AWS (e.g., AWS CDK, ECS, ALB, EC2); Strong understanding of containerisation (+ deployment) - Docker ; Experience designing and securing APIs ; Experience with LangGraph and/or building agentic AI systems ; Strong knowledge of databases – SQL (PostgreSQL or similar) and NoSQL ; Experience logging, monitoring, and debugging production systems; Ability to work in Unix/Linux environments and with Bash scripting. ✅ Soft skills and others: Robust software development best practices and documentation; Proactive and self-driven, able to identify opportunities and suggest tasks rather than waiting for assignments; Strong team player , comfortable collaborating and contributing in group settings; Strong communication skills; Positive mindset and constructive approach to challenges; Initiative-taker who is not afraid to lead or push ideas forward and deliver in a fast-paced environment; Eager to learn, grow, and continuously develop new skills; Fluent English (C1) for effective collaboration in an international environment; Location in Poland (at least 5 years), enabling smooth cooperation and occasional in-person team meetings; Availability up to one month . Moreover, we appreciate skills in these areas: 5+ years of experience in a similar senior role; Strong product mindset; Familiarity with CI/CD pipelines; Familiarity with Domino Data Lab; AWS CloudFormation, CloudFormation, Lambda; Nginx; Other Python frameworks like Flask; Experience with testing frameworks/tools (e.g. Playwright, Jest); Interest in Life Sciences and Drug Discovery. By joining us, you gain the following: Opportunity to work on exciting, international projects in cutting-edge industries like Automotive, Biotech, IoT; Possibility to develop in cloud technologies; Becoming part of a team that believes that the next step to a promising future is to put your heart into it and make it happen; Respect for your private life so you don't have to work overtime or on weekends; Team Events budget to socialize outside of work; Company Events to celebrate smaller and bigger successes (Summer Party, Programmer's Day, and trips abroad – so far we've been in South Africa, Are, and Barcelona). Perks and benefits: Fully remote work or in our office in Wrocław; Benefits such as Luxmed , Multisport , and life insurance in Nationale Nederlanden ; Attractive referral system (9,5k for senior, 6k for mid, 2,5k for junior); Personal Training Budget with additional paid hours; Passion Day - an extra day off for your hobby to spend as you please; Flexible working hours with no micro-management approach. Our core hours are 9-15, the rest of the working time is up to you; We provide high-quality work equipment + 2 additional monitors and accessories. If you apply for this position and match our expectations, then: 1) You will be invited to an HR Screening with our IT Recruiter. 2) You will have a technical interview. 3) You will meet with a client. Submit your application online in one easy step! Apply now! You will earn: B2B: 140 – 160 PLN net/hour + VAT

🏢 Summary: B2B Fullstack Engineer role focused on building and scaling secure applications to support genomic data science and AI-driven insights for disease research. The position involves developing React/Node.js and Python (FastAPI) solutions deployed on AWS, with strong emphasis on APIs, containerization, and production-grade systems. The project includes agentic AI systems and scalable cloud infrastructure. 🗂️ Requirements: Expertise in TypeScript and React, Expertise in Node.js, Expertise in Python and FastAPI, Experience with AWS services (CDK, ECS, ALB, EC2), Experience with Docker and containerization, Experience designing and securing APIs, Experience with SQL and NoSQL databases, Experience with logging, monitoring, and debugging production systems, Ability to work in Unix/Linux environments, Bash scripting skills, Experience with LangGraph or agentic AI systems, Fluent English (C1), Location in Poland 📃 Skills: TypeScript, JavaScript, React, Node.js, Python, FastAPI, AWS, CDK, ECS, ALB, EC2, Docker, SQL, PostgreSQL, NoSQL, Unix, Linux, Bash, LangGraph, CI/CD, CloudFormation, Lambda, Nginx, Flask, Playwright, Jest 🏢 Description: Holisticon Connect is a division within NEXER GROUP - a custom software development company. We started in Poland in 2017 and are now a team of over 140 people. We have the opportunity to work with world-renowned brands from Scandinavia, the UK, and Western Europe. Our goal is to grow stronger, in competence rather than in numbers.If you like what we do, check out our offer, maybe we will have the pleasure of meeting you! 😊 We are looking for a Fullstack Engineer to join a team that is expanding its genomic data science capabilities to explore data from multiple sources. The goal is to gain insights into the genomic drivers of common diseases and support the identification of novel therapeutic targets. We offer a B2B contract: 140 – 160 PLN net/hour + VAT You might be the perfect match if you are/have: ✅ Technical skills: Expertise in TypeScript (JavaScript) - React & Node.js; Expertise in Python (& FastAPI); Experience building and deploying secure and scalable apps in AWS (e.g., AWS CDK, ECS, ALB, EC2); Strong understanding of containerisation (+ deployment) - Docker ; Experience designing and securing APIs ; Experience with LangGraph and/or building agentic AI systems ; Strong knowledge of databases – SQL (PostgreSQL or similar) and NoSQL ; Experience logging, monitoring, and debugging production systems; Ability to work in Unix/Linux environments and with Bash scripting. ✅ Soft skills and others: Robust software development best practices and documentation; Proactive and self-driven, able to identify opportunities and suggest tasks rather than waiting for assignments; Strong team player , comfortable collaborating and contributing in group settings; Strong communication skills; Positive mindset and constructive approach to challenges; Initiative-taker who is not afraid to lead or push ideas forward and deliver in a fast-paced environment; Eager to learn, grow, and continuously develop new skills; Fluent English (C1) for effective collaboration in an international environment; Location in Poland (at least 5 years), enabling smooth cooperation and occasional in-person team meetings; Availability up to one month . Moreover, we appreciate skills in these areas: 5+ years of experience in a similar senior role; Strong product mindset; Familiarity with CI/CD pipelines; Familiarity with Domino Data Lab; AWS CloudFormation, CloudFormation, Lambda; Nginx; Other Python frameworks like Flask; Experience with testing frameworks/tools (e.g. Playwright, Jest); Interest in Life Sciences and Drug Discovery. By joining us, you gain the following: Opportunity to work on exciting, international projects in cutting-edge industries like Automotive, Biotech, IoT; Possibility to develop in cloud technologies; Becoming part of a team that believes that the next step to a promising future is to put your heart into it and make it happen; Respect for your private life so you don't have to work overtime or on weekends; Team Events budget to socialize outside of work; Company Events to celebrate smaller and bigger successes (Summer Party, Programmer's Day, and trips abroad – so far we've been in South Africa, Are, and Barcelona). Perks and benefits: Fully remote work or in our office in Wrocław; Benefits such as Luxmed , Multisport , and life insurance in Nationale Nederlanden ; Attractive referral system (9,5k for senior, 6k for mid, 2,5k for junior); Personal Training Budget with additional paid hours; Passion Day - an extra day off for your hobby to spend as you please; Flexible working hours with no micro-management approach. Our core hours are 9-15, the rest of the working time is up to you; We provide high-quality work equipment + 2 additional monitors and accessories. If you apply for this position and match our expectations, then: 1) You will be invited to an HR Screening with our IT Recruiter. 2) You will have a technical interview. 3) You will meet with a client. Submit your application online in one easy step! Apply now!

🏢 Summary: Backend/Full-Stack Developer role focused on building and evolving a large-scale, cloud-native, event-driven system used across multiple markets. The position involves developing Kotlin-based microservices, integrating event streaming solutions, and contributing to React frontend components closely connected with backend services. The role emphasizes scalable architecture, clean code, and reliable cloud deployment in an international product team. 🗂️ Requirements: Minimum 5 years of experience as Backend Developer, Strong knowledge of Kotlin, Strong knowledge of Spring Boot, Solid knowledge of SQL, Experience with PostgreSQL, Experience in microservices architecture, Experience with Apache Kafka, Experience with asynchronous communication, Experience with AWS, Experience with Kubernetes, Experience building REST APIs, Experience with Git, Knowledge of JavaScript or TypeScript, Experience with React, Understanding of frontend-backend integration, Knowledge of distributed systems fundamentals, Experience writing unit tests, Experience writing integration tests, Experience writing end-to-end tests, Fluent English (C1), Based in Poland 📃 Skills: Kotlin, Spring, SpringBoot, SQL, PostgreSQL, Kafka, AWS, Kubernetes, REST, Git, JavaScript, TypeScript, React, Microservices, Docker 🏢 Description: Holisticon Connect is a division within NEXER GROUP - a custom software development company. We started in Poland in 2017 and are now a team of over 140 people. We have the opportunity to work with world-renowned brands from Scandinavia, the UK, and Western Europe. Our goal is to grow stronger, in competence rather than in numbers. If you like what we do, check out our offer, maybe we will have the pleasure of meeting you! 😊 We are looking for a Backend/Full-Stack Developer to join an international product team building a large-scale internal system used daily across multiple markets. The product plays a key role in an ongoing digital transformation and is built as a set of scalable, event-driven microservices running in a cloud environment. You will work in a cross-functional team with Frontend Developers, UX Designers, and a Product Owner, contributing to backend services as well as selected frontend areas that require close backend integration, high reliability, performance, and clean architecture. We offer competitive remuneration: B2B: 110 – 145 PLN net/hour + VAT Key Responsibilities Design, develop, and maintain backend services using Kotlin and Spring Boot; Build and evolve microservices with asynchronous communication patterns; Implement and integrate event-driven solutions using Apache Kafka; Work with relational databases, primarily PostgreSQL, ensuring data consistency and performance; Develop and consume REST APIs used by frontend applications and other services; Contribute to frontend application development using React, especially in areas closely connected to backend integrations and business logic; Collaborate with Frontend Developers and UX Designers to deliver consistent, end-to-end solutions across backend services and user-facing applications; Write unit, integration, and end-to-end tests within the Kotlin ecosystem; Support frontend reliability and maintainability by designing clean service contracts and integration-friendly APIs; Deploy and operate services in a cloud-native environment (AWS, Kubernetes); Participate in code reviews and contribute to engineering standards and best practices; Use AI tools responsibly to improve development efficiency and code quality. You might be the perfect match if you are/have: At least 5 years of experience working as a Backend Developer ; Excellent knowledge of Kotlin and Spring Boot , with a solid understanding of SQL (PostgreSQL preferred); Very good command of English (C1), both written and spoken; Hands-on experience designing services in a microservices architecture; Experience working with Apache Kafka and asynchronous communication; Ability to work in a cloud environment, including AWS and Kubernetes; Practical experience with Git and building REST APIs; Practical knowledge of JavaScript or TypeScript and modern frontend development practices; Practical understanding of frontend-backend integration and how React applications communicate with backend services through APIs; Understanding of system design fundamentals in distributed systems; Experience writing unit, integration, and end-to-end tests in the Kotlin ecosystem; A strong focus on clean, maintainable, and readable code; A proactive, communicative team player with an open and collaborative mindset; Based in Poland, with availability for occasional in-person team meetings. Moreover, we appreciate skills in these areas: Experience with Kubernetes and container orchestration; Hands-on experience with cloud platforms, especially AWS; Familiarity with event-driven and message-based architectures; Experience working on large-scale or enterprise-level systems; Experience with TypeScript and the modern React ecosystem; Familiarity with frontend architecture, state management, and component-based design; Understanding of usability and performance considerations in web applications; Willingness to take ownership and influence technical decisions. By joining us, you gain the following: Opportunity to work on exciting, international projects in cutting-edge industries like Automotive, Biotech, IoT; Possibility to develop in cloud technologies; Becoming part of a team that believes that the next step to a promising future is to put your heart into it and make it happen; Respect for your private life so you don't have to work overtime or on weekends; Team Events budget to socialize outside of work; Company Events to celebrate smaller and bigger successes (Summer Party, Programmer's Day, and trips abroad – so far we've been in South Africa, Are, and Barcelona). Perks and benefits: Fully remote work or in our office in Wrocław; Benefits such as Luxmed , Multisport , and life insurance in Nationale Nederlanden ; Attractive referral system (9,5k for senior, 6k for mid, 2,5k for junior); Personal Training Budget with additional paid hours; Passion Day - an extra day off for your hobby to spend as you please; Flexible working hours with no micro-management approach. Our core hours are 9-15, the rest of the working time is up to you; We provide high-quality work equipment + 2 additional monitors and accessories. If you apply for this position and match our expectations, then: 1) You will be invited to an HR Screening with our IT Recruiter. 2) You will have a technical interview. 3) You will meet with a client. Submit your application online in one easy step! Apply now! You will earn: B2B: 110 – 145 PLN net/hour + VAT

🏢 Summary: Frontend Developer role in an international product team building a large-scale internal web system as part of a digital transformation initiative. The position focuses on developing high-quality, performant, and maintainable frontend solutions using modern technologies within a cross-functional team. The project emphasizes reliability, scalability, and user-centric design. 🗂️ Requirements: Minimum 5 years of experience as Frontend Developer, Excellent knowledge of React, Excellent knowledge of JavaScript, Excellent knowledge of TypeScript, Hands-on experience with Redux, Hands-on experience with TanStack Query, Experience with REST APIs integration, Experience with Git, Experience writing unit tests, Experience writing integration tests, Experience writing end-to-end tests, Very good English (C1), Experience with microservices architecture, Basic experience with Kotlin, Basic experience with Spring, Based in Poland 📃 Skills: React, JavaScript, TypeScript, Redux, TanStack, REST, Git, Playwright, Selenium, Kotlin, Spring, Microservices, HTML, CSS 🏢 Description: Holisticon Connect is a division within NEXER GROUP - a custom software development company. We started in Poland in 2017 and are now a team of over 140 people. We have the opportunity to work with world-renowned brands from Scandinavia, the UK, and Western Europe. Our goal is to grow stronger, in competence rather than in numbers. If you like what we do, check out our offer, maybe we will have the pleasure of meeting you! 😊 We are looking for a Frontend Developer to join an international product team working on a large-scale internal system used daily by users across multiple markets. The product is a key part of an ongoing digital transformation and focuses on delivering reliable, modern, and user-friendly solutions for real business needs. You will work in a cross-functional team alongside UX Designers, Backend Developers, and a Product Owner, contributing to the development of a complex web application where quality, performance, and maintainability truly matter. We offer a competitive renumeration: B2B: 110 – 145 PLN net/hour + VAT Key Responsibilities: Develop and maintain modern frontend applications using React , TypeScript , and JavaScript; Collaborate closely with UX Designers to translate designs into high-quality user interfaces; Integrate frontend solutions with backend services via REST APIs; Manage application state using Redux and TanStack Query; Write unit, integration, and end-to-end tests to ensure application quality and stability; Participate in code reviews and contribute to shared frontend standards; Actively collaborate within the team and across teams to deliver robust, scalable solutions; Use AI tools responsibly to improve development efficiency and code quality. You might be the perfect match if you are / have: At least 5 years of experience working as a Frontend Developer; Excellent knowledge of React , JavaScript , and TypeScript; Very good command of English (C1) , both written and spoken; Hands-on experience with Redux and TanStack Query; Practical experience with Git and working with REST APIs; Experience in writing unit, integration, and end-to-end tests (e.g. React Testing Library, Playwright, Selenium); Awareness of effective and responsible usage of AI models to improve development efficiency; Some experience with microservices and backend technologies such as Kotlin and Spring; A strong focus on writing clean, maintainable, and readable code; A proactive, communicative team player who values collaboration; Based in Poland , with availability for occasional in-person team meetings. Moreover, we appreciate skills in these areas: Experience working on large-scale or enterprise-level applications; Familiarity with design systems and close collaboration with UX teams; Understanding of performance optimization and frontend architecture; Experience working in agile, cross-functional teams; Openness to learning beyond frontend and understanding the broader system context. By joining us, you gain the following: Opportunity to work on exciting, international projects in cutting-edge industries like Automotive, Biotech, IoT; Possibility to develop in cloud technologies; Becoming part of a team that believes that the next step to a promising future is to put your heart into it and make it happen; Respect for your private life so you don't have to work overtime or on weekends; Team Events budget to socialize outside of work; Company Events to celebrate smaller and bigger successes (Summer Party, Programmer's Day, and trips abroad – so far we've been in South Africa, Are, and Barcelona). Perks and benefits: Fully remote work or in our office in Wrocław; Benefits such as Luxmed , Multisport , and life insurance in Nationale Nederlanden ; Attractive referral system (9,5k for senior, 6k for mid, 2,5k for junior); Personal Training Budget with additional paid hours; Passion Day - an extra day off for your hobby to spend as you please; Flexible working hours with no micro-management approach. Our core hours are 9-15, the rest of the working time is up to you; We provide high-quality work equipment + 2 additional monitors and accessories. If you apply for this position and match our expectations, then: 1) You will be invited to an HR Screening with our IT Recruiter. 2) You will have a technical interview. 3) You will meet with a client. Submit your application online in one easy step! Apply now! You will earn: B2B: 110 – 145 PLN net/hour + VAT

🏢 Summary: B2B opportunity for an experienced Frontend Developer to build data-driven applications supporting scientific research and therapeutic target discovery. The role focuses on developing and optimizing modern React-based interfaces integrated with backend systems and cloud environments. You will collaborate in cross-functional teams delivering scalable solutions for clinical and research data platforms. 🗂️ Requirements: 4+ years experience as Frontend Developer, Strong JavaScript and TypeScript proficiency, Commercial experience with React (hooks, state management, architecture, performance), Experience with REST API design and integration, Practical experience with Node.js, Knowledge of modern frontend tooling (Webpack or Vite, ESLint, Prettier), Experience with testing frameworks, Experience with design systems and component libraries, Knowledge of accessibility standards and responsive design, Understanding of clean code and modular design principles, Good knowledge of Python 3.x, Knowledge of relational and NoSQL databases, Experience with Docker, Experience with AWS or GCP, Experience with Unix or Linux and Bash, Fluent English (C1) 📃 Skills: JavaScript, TypeScript, React, REST, Node.js, Webpack, Vite, ESLint, Prettier, Python, PostgreSQL, Snowflake, DynamoDB, Docker, AWS, GCP, Linux, Unix, Bash, Playwright, Cypress, Jest, FastAPI, Flask 🏢 Description: Holisticon Connect is a division within NEXER GROUP - a custom software development company. We started in Poland in 2017 and are now a team of over 140 people. We have the opportunity to work with world-renowned brands from Scandinavia, the UK, and Western Europe. Our goal is to grow stronger, in competence rather than in numbers.If you like what we do, check out our offer, maybe we will have the pleasure of meeting you! 😊 We are looking for a Frontend Developer to join a team whose main mission is to deliver data to scientists. This data is used to identify new therapeutic targets within the research and development program and to provide human genetics insights for clinical research. We offer a B2B contract: 130 – 150 PLN net/hour + VAT You might be the perfect match if you are/have: ✅ Core technical skills: 4+ years of experience as a Frontend Developer; Strong proficiency in JavaScript/TypeScript with solid experience in React (hooks, state management, component architecture, performance optimisation); Experience in API design and integration (REST) and effective collaboration with backend teams; Practical experience with Node.js for tooling, build scripts or lightweight backend services; Good understanding of modern frontend tooling and ecosystem : Webpack/Vite, ESLint/Prettier, package managers, testing frameworks; Experience working with design systems , component libraries, accessibility standards and responsive UI; Strong understanding of software engineering best practices — clean code, modular design, code reviews, documentation. ✅ Complementary full-stack strengths: Good knowledge of Python (3.x) as a supporting skill in cross-functional environments; Understanding of relational and NoSQL databases (Postgres, Snowflake, DynamoDB); Experience with Docker and cloud platforms (AWS / GCP), supporting efficient FE–BE integration; Comfortable working in Unix/Linux environments and with Bash scripting. ✅ Ways of working: Proactive and self-driven, able to propose improvements and push initiatives forward; Strong team player with great communication skills; comfortable participating in design discussions and code reviews; Positive, solution-oriented mindset; Quick learner, eager to grow and expand technical skills; Fluent English (C1) for effective collaboration in international environments; Location in Poland (at least 5 years); Available within one month . Moreover, we appreciate skills in these areas: Experience with CI/CD pipelines for building and deploying FE applications; Familiarity with Python frameworks like FastAPI/Flask (useful in integration work); Experience with testing tools such as Playwright , Cypress, or Jest; Interest in Life Sciences/Drug Discovery domain. By joining us, you gain the following: Opportunity to work on exciting, international projects in cutting-edge industries like Automotive, Biotech, IoT; Possibility to develop in cloud technologies; Becoming part of a team that believes that the next step to a promising future is to put your heart into it and make it happen; Respect for your private life so you don't have to work overtime or on weekends; Team Events budget to socialize outside of work; Company Events to celebrate smaller and bigger successes (Summer Party, Programmer's Day, and trips abroad – so far we've been in South Africa, Are, and Barcelona). Perks and benefits: Fully remote work or in our office in Wrocław; Benefits such as Luxmed , Multisport , and life insurance in Nationale Nederlanden ; Attractive referral system (9,5k for senior, 6k for mid, 2,5k for junior); Personal Training Budget with additional paid hours; Passion Day - an extra day off for your hobby to spend as you please; Flexible working hours with no micro-management approach. Our core hours are 9-15, the rest of the working time is up to you; We provide high-quality work equipment + 2 additional monitors and accessories. If you apply for this position and match our expectations, then: 1) You will be invited to an HR Screening with our IT Recruiter. 2) You will have a technical interview. 3) You will meet with a client. Submit your application online in one easy step! Apply now!

🏢 Summary: Senior Fullstack Engineer role focused on building AI-driven pharmatech solutions using React and Python for a UK-based client. The position involves equal work on frontend and backend, contributing to feature design in a small, international Scrum-based team. The project leverages modern technologies to develop software supporting drug discovery in Life Sciences. 🗂️ Requirements: 5+ years experience as Fullstack Engineer in commercial projects, Strong experience with Python 3.x, Proficiency in JavaScript and TypeScript, Commercial experience with React, Experience with Django, DRF and Django ORM, Experience with relational databases (Postgres, Snowflake or Oracle), Experience working with cloud environments (GCP preferred), Fluent English (C1), Residence in Poland 📃 Skills: Python, Django, DRF, ORM, JavaScript, TypeScript, React, PostgreSQL, Snowflake, Oracle, GCP, CI/CD, FastAPI, Flask, Scrum 🏢 Description: Holisticon Connect is a division within NEXER GROUP - a custom software development company. We started in Poland in 2017 and are now a team of over 140 people with offices in Wrocław, Warsaw, and Cracow. We have the opportunity to work with world-renowned brands from Scandinavia, the UK, and Western Europe. Our goal is to grow stronger, in competence rather than in numbers. If you like what we do, check out our offer, maybe we will have the pleasure of meeting you! 😊 We are looking for Senior Fullstack Engineer with extensive experience in React and Python . Working on this position, you can expect that: Our client is a UK-based AI-driven Pharmatech . You will become a part of interesting industry, especially if you like things like Life Sciences/Medicine. You can work on software that can change the face of inventing new drags . You will work with modern technologies and the newest versions: React 18, TypeScript, Python 3.8+ and Django ; You will cooperate with very experienced engineers in an i nternational environment on daily basis; The team is small (4-6 p.) and uses some elements of Scrum to organise their way of working – generally there is not many meetings and you actually have time to do your work; You will work equally on the frontend and backend side; From the project level, you will have an influence on new features design and requirements. What do the Engineers working on the project say: “We participate in sprint level planning as well as quarterly and annual planning; as a developer, I feel I have a voice in the decisions made.”“In my opinion the best foreign team of the three I have worked for. As far as the people are concerned they are all very nice and cool”. Hey YOU clever one, if reading this add, you feel an instant need to dive into practical techniques that boost Python’s performance, read the article of engineer who actually works in the project of our client :) You will find it HERE We offer a choice of employment form: B2B or Employment Contract UoP: 20 000 – 22 000 PLN gross/month B2B: 150 – 170 PLN net/hour + VAT You might be the perfect match if you are/have: At least 5+ years working as a Fullstack Engineer in commercial projects; A real comfort working in the Python language (pref. 3.x); Proficiency in JavaScript/TypeScript and React ; Knowledge of Django (DRF and Django ORM); Hands-on experience with database technologies such as Postgres, Snowflake or Oracle; Eager to work with cloud environment (preferred GCP); Fluent English (C1) to work seamlessly in an international environment; Location in Poland to facilitate collaboration and attendance at occasional team meetings. Moreover, we appreciate skills in these areas: Many years' experience in a similar role Familiarity with CI/CD pipelines; Other Python frameworks like FastAPI, Flask; Interest in Life Sciences and Drug Discovery . By joining us, you gain the following: Opportunity to work on exciting, international projects in cutting-edge industries like Automotive, Biotech, IoT; Possibility to develop in cloud technologies; Becoming part of a team that believes that the next step to a promising future is to put your heart into it and make it happen; Respect for your private life so you don't have to work overtime or on weekends; Team Events budget to socialize outside of work; Company Events to celebrate smaller and bigger successes (Summer Party, Programmer's Day, and trips abroad – so far we've been in South Africa, Are, and Barcelona). Perks and benefits: Fully remote work or in our office in Wrocław; Benefits such as Luxmed , Multisport , and life insurance in Nationale Nederlanden ; Attractive referral system (9,5k for senior, 6k for mid, 2,5k for junior); Personal Training Budget with additional paid hours; Passion Day - an extra day off for your hobby to spend as you please; Flexible working hours with no micro-management approach. Our core hours are 9-15, the rest of the working time is up to you; We provide high-quality work equipment + 2 additional monitors and accessories. If you apply for this position and match our expectations, then: 1) You will be invited to talk with an IT Recruiter , to get more information about the project, and to ensure that we fulfil your expectations; 2) The next online meeting will be focused on technical verification; 3) The last stage is about getting to know you better. We will set up a short online meeting with a client. Submit your application online in one easy step! Apply now! You will earn: UoP: 20 000 – 22 000 PLN gross/month B2B: 150 – 170 PLN net/hour + VAT

🏢 Summary: Backend Developer role in an international product team building a large-scale, cloud-based internal system using event-driven microservices. The position focuses on designing and maintaining high-performance backend services in Kotlin and Spring Boot within a distributed architecture. You will contribute to scalable, reliable solutions deployed in AWS and Kubernetes environments. 🗂️ Requirements: 5+ years of Backend Developer experience, Strong Kotlin knowledge, Strong Spring Boot knowledge, Solid SQL knowledge, Experience with PostgreSQL, Experience in microservices architecture, Experience with Apache Kafka, Experience with asynchronous communication, Experience with AWS, Experience with Kubernetes, Experience building REST APIs, Experience with Git, Experience writing unit tests, Experience writing integration tests, Experience writing end-to-end tests, Understanding of distributed systems design, English level C1, Based in Poland 📃 Skills: Kotlin, Spring, SpringBoot, SQL, PostgreSQL, Kafka, AWS, Kubernetes, REST, Git, Microservices, Docker, JUnit 🏢 Description: Holisticon Connect is a division within NEXER GROUP - a custom software development company. We started in Poland in 2017 and are now a team of over 140 people. We have the opportunity to work with world-renowned brands from Scandinavia, the UK, and Western Europe. Our goal is to grow stronger, in competence rather than in numbers. If you like what we do, check out our offer, maybe we will have the pleasure of meeting you! 😊 We are looking for a Backend Developer to join an international product team building a large-scale internal system used daily across multiple markets. The product plays a key role in an ongoing digital transformation and is built as a set of scalable, event-driven microservices running in a cloud environment. You will work in a cross-functional team with Frontend Developers, UX Designers, and a Product Owner, contributing to backend services that require high reliability, performance, and clean architecture. We offer a competitive renumeration: B2B: 110 – 145 PLN net/hour + VAT Key Responsibilities: Design, develop, and maintain backend services using Kotlin and Spring Boot; Build and evolve microservices with asynchronous communication patterns; Implement and integrate event-driven solutions using Apache Kafka; Work with relational databases, primarily PostgreSQL , ensuring data consistency and performance; Develop and consume REST APIs used by frontend and other services; Write unit, integration, and end-to-end tests within the Kotlin ecosystem; Deploy and operate services in a cloud-native environment (AWS, Kubernetes); Participate in code reviews and contribute to backend standards and best practices; Use AI tools responsibly to improve development efficiency and code quality. You might be the perfect match if you are / have: At least 5 years of experience working as a Backend Developer; Excellent knowledge of Kotlin and Spring Boot , with a solid understanding of SQL (PostgreSQL preferred); Very good command of English (C1) , both written and spoken; Hands-on experience designing services in a microservices architecture; Experience working with Apache Kafka and asynchronous communication; Ability to work in a cloud environment , including AWS and Kubernetes; Practical experience with Git and building REST APIs; Understanding of system design fundamentals in distributed systems; Experience writing unit, integration, and end-to-end tests in the Kotlin ecosystem; A strong focus on clean, maintainable, and readable code; A proactive, communicative team player with an open and collaborative mindset; Based in Poland , with availability for occasional in-person team meetings. Moreover, we appreciate skills in these areas: Experience with Kubernetes and container orchestration; Hands-on experience with cloud platforms , especially AWS; Familiarity with event-driven and message-based architectures; Experience working on large-scale or enterprise-level systems; Willingness to take ownership and influence technical decisions. By joining us, you gain the following: Opportunity to work on exciting, international projects in cutting-edge industries like Automotive, Biotech, IoT; Possibility to develop in cloud technologies; Becoming part of a team that believes that the next step to a promising future is to put your heart into it and make it happen; Respect for your private life so you don't have to work overtime or on weekends; Team Events budget to socialize outside of work; Company Events to celebrate smaller and bigger successes (Summer Party, Programmer's Day, and trips abroad – so far we've been in South Africa, Are, and Barcelona). Perks and benefits: Fully remote work or in our office in Wrocław; Benefits such as Luxmed , Multisport , and life insurance in Nationale Nederlanden ; Attractive referral system (9,5k for senior, 6k for mid, 2,5k for junior); Personal Training Budget with additional paid hours; Passion Day - an extra day off for your hobby to spend as you please; Flexible working hours with no micro-management approach. Our core hours are 9-15, the rest of the working time is up to you; We provide high-quality work equipment + 2 additional monitors and accessories. If you apply for this position and match our expectations, then: 1) You will be invited to an HR Screening with our IT Recruiter. 2) You will have a technical interview. 3) You will meet with a client. Submit your application online in one easy step! Apply now! You will earn: B2B: 110 – 145 PLN net/hour + VAT

🏢 Summary: Senior Software Engineer role focused on end-to-end ownership of core Python services powering computational pathology and image analysis in an AI-driven Oncology R&D environment. The position involves designing and evolving microservice architecture, ensuring scalability, reliability, and performance across distributed systems deployed on Kubernetes and AWS. The engineer will drive technical decisions and operational excellence in a production-grade cloud environment. 🗂️ Requirements: M.Sc. in Computer Science/Engineering or equivalent experience, Expert-level production experience with Python, Hands-on experience with Go, Strong knowledge of microservices architectures, Experience with distributed systems, Experience designing REST APIs, Experience with gRPC, Experience with SQL databases, Experience with NoSQL databases, Experience with object storage (S3), Experience deploying and operating services on Kubernetes, Strong Unix fundamentals, Strong Linux fundamentals, Experience with AWS services (EKS, EC2, S3, RDS, IAM, CloudWatch), Experience with CI/CD pipelines, Experience with automated testing, Security-focused engineering practices, Ability to lead technical initiatives 📃 Skills: Python, Go, Kubernetes, AWS, EKS, EC2, S3, RDS, IAM, CloudWatch, REST, gRPC, SQL, NoSQL, Unix, Linux, Microservices, DistributedSystems, CI/CD 🏢 Description: Holisticon Connect is a division within NEXER GROUP - a custom software development company. We started in Poland in 2017 and are now a team of over 140 people. We have the opportunity to work with world-renowned brands from Scandinavia, the UK, and Western Europe. Our goal is to grow stronger, in competence rather than in numbers. If you like what we do, check out our offer, maybe we will have the pleasure of meeting you! 😊 We are looking for a Senior Software Engineer (Python, Go, Kubernetes). You will take end-to-end ownership of core Python services that power computational pathology and image analysis within Oncology R&D AI, keeping them robust, scalable, and well maintained. You’ll help shape our microservice architecture by defining clear service boundaries and interfaces, guiding key design decisions, and driving improvements in reliability and performance across the platform. We offer a choice of employment form: B2B or Employment Contract UoP: 17 000 – 20 000 PLN gross/month B2B: 140 – 170 PLN net/hour + VAT You might be the perfect match if you are/have: M.Sc . in Computer Science/Engineering (or equivalent) or comparable industry experience. Expert-level production experience with Python and solid hands-on experience with Golang for building and operating services. Deep understanding of microservices, distributed systems, and API design ( REST/gRPC ), with a focus on clean contracts and handling failure modes. Practical experience with SQL and NoSQL databases, including schema design, performance tuning, and familiarity with object storage solutions (e.g., S3). Proven experience deploying and operating services on Kubernetes , along with strong Unix/Linux fundamentals. Practical knowledge of key AWS services (EKS, EC2, S3, RDS, IAM, CloudWatch) and the ability to design cost‑efficient architectures. Strong engineering practices, including CI/CD, automated testing, code reviews, documentation, and a security-first mindset. Ability to lead technical initiatives, clearly communicate trade-offs, and collaborate effectively across multidisciplinary teams. Moreover, we appreciate skills in these areas: Experience with ML/AI tooling such as PyTorch , Kubeflow, MLflow, Feast, Argo, Airflow, Ray , and model versioning/monitoring solutions. Experience with large-scale image processing or digital pathology data (e.g., whole‑slide images) using libraries such as OpenSlide , scikit-image, or OpenCV . Experience with performance engineering, including concurrency, memory profiling, high‑throughput data pipelines, and GPU/accelerator integration. Experience working in regulated environments (e.g., GxP), including data governance, privacy requirements, and developing software under regulated processes. Experience with JavaScript/TypeScript for building internal tools and dashboards. Experience with event‑driven architectures and streaming platforms (e.g., Kafka ). By joining us, you gain the following: Opportunity to work on exciting, international projects in cutting-edge industries like Automotive, Biotech, IoT; Possibility to develop in cloud technologies; Becoming part of a team that believes that the next step to a promising future is to put your heart into it and make it happen; Respect for your private life so you don't have to work overtime or on weekends; Team Events budget to socialize outside of work; Company Events to celebrate smaller and bigger successes (Summer Party, Programmer's Day, and trips abroad – so far we've been in South Africa, Are, and Barcelona). Perks and benefits: Fully remote work or in our office in Wrocław; Benefits such as Luxmed , Multisport , and life insurance in Nationale Nederlanden ; Attractive referral system (9,5k for senior, 6k for mid, 2,5k for junior); Personal Training Budget with additional paid hours; Passion Day - an extra day off for your hobby to spend as you please; Flexible working hours with no micro-management approach. Our core hours are 9-15, the rest of the working time is up to you; We provide high-quality work equipment + 2 additional monitors and accessories. If you apply for this position and match our expectations, then: You will be invited for an HR screening to get to know your experience, expectations, and motivation; You will complete a coding test (HackerRank) to demonstrate your technical skills; You will be invited for a technical interview (~60 minutes) to discuss your approach, problem-solving, and frontend expertise in more depth; You will meet the team members to learn more about the project and see how we collaborate on a daily basis. Submit your application online in one easy step! Apply now!