Senior Node.js Developer

🏢 Summary: Senior .NET Developer role focused on designing, building, and maintaining scalable .NET applications and APIs across diverse projects, including AI-driven and legacy modernization initiatives. The position involves backend development, architectural input, code quality improvement, and cloud-based deployments within Agile teams. B2B contract with flexible remote collaboration. 🗂️ Requirements: 5+ years experience with C# and .NET, .NET Core / .NET 6+ experience, ASP.NET Core experience, Entity Framework experience, Experience building RESTful APIs, SQL and NoSQL database experience, Cloud platform experience (AWS, Azure, or GCP), CI/CD pipeline knowledge, Git version control proficiency, Understanding of OOP and design patterns, Experience in Agile/Scrum, English level B2+ 📃 Skills: C#, .NET, .NETCore, ASP.NET, EntityFramework, REST, SQL, PostgreSQL, MySQL, MongoDB, AWS, Azure, GCP, CI/CD, Git, OOP, Scrum, AI 🏢 Description: Who we are: We are Inspeerity (part of DevelopX group), engineering consultancy providing software development and consultancy. Our primary expertise is systems architecture and full stack development – from defining project requirements, to designing, building, and deploying software applications for web, backend, enterprise and mobile. We are crazy about technology, serious about people. About position: We are currently building our talent pool for future Senior .NET Developer roles. As our company is expanding, you may have the opportunity to work on a variety of software solutions across multiple initiatives, including projects we will be delivering in the future, from building native AI solutions to modernizing legacy systems. If you enjoy collaborating in a skilled team and are committed to delivering top-notch software, we’d love to connect. We're not prescriptive about background. Whether you've worked in fintech, SaaS, e-commerce, or enterprise systems, what matters is that you've shipped production software at scale, cared about its reliability, and learned from what broke. TL;DR • Who: Senior .NET Developer • Contract Type: B2B Framework Agreement • Salary range: Up to 150 PLN/h • Company: Software House What you’ll be doing: • Designing, implementing, and maintaining high-quality .NET applications. • Developing backend components and APIs to support scalable software solutions. • Collaborating with cross-functional teams. • Reviewing and refactoring code to ensure maintainability, performance, and security. • Participating in technical design discussions and contributing to architecture decisions. • Writing and maintaining technical documentation for systems, APIs, and processes. • Supporting deployment and integration of applications in different environments. You will be the best fit if you have: • 5+ years of experience as a C#/.NET developer, preferably with exposure to .NET Core / .NET 6+ , ASP.NET Core , Entity Framework or similar frameworks. • Strong understanding of object-oriented programming, design patterns, and clean code principles. • Experience with RESTful APIs and web services integration. • Familiarity with SQL and NoSQL databases (e.g., PostgreSQL, MySQL, MongoDB). • Experience with cloud environments such as AWS, Azure, or GCP. • Knowledge of CI/CD pipelines and version control systems (e.g., Git). • Strong problem-solving skills and ability to troubleshoot complex issues. • English level B2 or higher. • Experience working in Agile/Scrum teams and contributing to iterative development. • Experience with AI technologies, including using AI tools for development and building AI-powered features or applications. What we offer • Remote work or working from our Bialystok, Warsaw, Rzeszow offices. It's up to you! • Collaboration with experienced and engaged people who will appreciate your work and support you whenever you need it 😊 • Hybrid and flexible cooperation model based on a B2B Framework Agreement. • Great working conditions and best equipment: Dell or MacBook, your choice. Good to know: We don’t require a degree. We don’t do whiteboard puzzles or trick questions. Our interview process is practical: a technical conversation, and a chat about how you work. We value direct communication and intellectual curiosity. If you’re someone who gets excited debugging a tricky concurrency issue - not because you have to, but because you want to understand it — we’ll get along well.

🏢 Summary: B2B contract role for a Senior Java Developer focused on designing and maintaining scalable backend systems and APIs across diverse software projects, including AI-driven and legacy modernization initiatives. The position involves architectural input, code quality improvements, and deployment support in cloud environments within Agile teams. 🗂️ Requirements: Minimum 5 years of experience as a Java Developer, Commercial experience with Spring Boot or Hibernate, Strong knowledge of object-oriented programming and design patterns, Experience building and integrating RESTful APIs, Experience with SQL and NoSQL databases, Experience with cloud platforms (AWS, Azure, or GCP), Knowledge of CI/CD pipelines and version control systems, Experience working in Agile/Scrum teams, English proficiency at B2 level or higher, Experience with AI technologies or AI-powered solutions 📃 Skills: Java, Spring, SpringBoot, Hibernate, REST, SQL, NoSQL, PostgreSQL, MySQL, MongoDB, AWS, Azure, GCP, CI/CD, Git, OOP, Scrum, AI 🏢 Description: About position: We are currently building our talent pool for future Senior Java Developer roles. As our company is expanding, you may have the opportunity to work on a variety of software solutions across multiple initiatives, including projects we will be delivering in the future, from building native AI solutions to modernizing legacy systems. If you enjoy collaborating in a skilled team and are committed to delivering top-notch software, we’d love to connect. We're not prescriptive about background. Whether you've worked in fintech, SaaS, e-commerce, or enterprise systems, what matters is that you've shipped production software at scale, cared about its reliability, and learned from what broke. Who we are: We are Inspeerity (part of DevelopX group), engineering consultancy providing software development and consultancy. Our primary expertise is systems architecture and full stack development – from defining project requirements, to designing, building, and deploying software applications for web, backend, enterprise and mobile. We are crazy about technology, serious about people. TL;DR • Who : Senior Java Developer • Contract Type : B2B Framework Agreement. • Salary range: Up to 150 PLN/h • Company : Software House What you’ll be doing: Designing, implementing, and maintaining high-quality Java applications. Developing backend components and APIs to support scalable software solutions. Collaborating with cross-functional teams. Reviewing and refactoring code to ensure maintainability, performance, and security. Participating in technical design discussions and contributing to architecture decisions. Writing and maintaining technical documentation for systems, APIs, and processes. Supporting deployment and integration of applications in different environments. You will be the best fit if you have: 5 years of experience as a Java developer, preferably with exposure to Spring Boot, Hibernate, or similar frameworks. Strong understanding of object-oriented programming, design patterns, and clean code principles. Experience with RESTful APIs and web services integration. Familiarity with SQL and NoSQL databases (e.g., PostgreSQL, MySQL, MongoDB). Experience with cloud environments such as AWS, Azure, or GCP. Knowledge of CI/CD pipelines and version control systems (e.g., Git). Strong problem-solving skills and ability to troubleshoot complex issues. English level B2 or higher. Experience working in Agile/Scrum teams and contributing to iterative development. Experience with AI technologies, including using AI tools for development and building AI-powered features or applications. What we offer : Remote work or working from our Bialystok, Warsaw, Rzeszow offices. It's up to you! Collaboration with experienced and engaged people who will appreciate your work and support you whenever you need it 😊 Hybrid and flexible cooperation model based on a B2B Framework Agreement. Great working conditions and best equipment: Dell or MacBook, your choose. Good to know: We don’t require a degree. We don’t do whiteboard puzzles or trick questions. Our interview process is practical: a technical conversation and a chat about how you work. We value direct communication and intellectual curiosity. If you’re someone who gets excited about debugging a tricky concurrency issue - not because you have to, but because you want to understand it — we’ll get along well.

🏢 Summary: Offer for a Senior Frontend Developer specializing in Angular to design, build, and maintain scalable, high-quality web applications within diverse software projects. The role involves frontend architecture decisions, integration with backend services, and collaboration in Agile teams. Contract is B2B with remote flexibility and focus on delivering production-grade solutions. 🗂️ Requirements: 5+ years Frontend development experience, Strong Angular 2+ expertise, Proficiency in JavaScript and TypeScript, Knowledge of HTML5 and CSS3, Experience with NgRx or state management, Experience integrating REST APIs, Familiarity with Webpack, Vite, npm or yarn, Experience with testing frameworks, Knowledge of CI/CD pipelines, Proficiency with Git, Experience in Agile/Scrum, English B2 or higher, Experience with AI tools or AI-powered features 📃 Skills: Angular, JavaScript, TypeScript, HTML5, CSS3, NgRx, REST, Webpack, Vite, npm, yarn, Jasmine, Karma, Cypress, Git, CICD, Agile, Scrum, AI 🏢 Description: Who we are: We are Inspeerity (part of DevelopX group), engineering consultancy providing software development and consultancy. Our primary expertise is systems architecture and full stack development – from defining project requirements, to designing, building, and deploying software applications for web, backend, enterprise and mobile. We are crazy about technology, serious about people. About position: We are currently building our talent pool for future Senior Frontend Developer (Angular) roles. As our company is expanding, you may have the opportunity to work on a variety of software solutions across multiple initiatives, including projects we will be delivering in the future, from building native AI solutions to modernizing legacy systems. If you enjoy collaborating in a skilled team and are committed to delivering top-notch software, we’d love to connect. We're not prescriptive about background. Whether you've worked in fintech, SaaS, e-commerce, or enterprise systems - what matters is that you've shipped production software at scale, cared about its reliability, and learned from what broke. TL;DR • Who: Senior Frontend Developer (Angular) • Contract Type: B2B Framework Agreement • Salary range: Up to 140 PLN/h • Company: Software House What you’ll be doing: • Designing, implementing, and maintaining high-quality frontend applications using Angular. • Building responsive, user-friendly interfaces and reusable UI components. • Collaborating with cross-functional teams including backend developers, designers, and product stakeholders. • Reviewing and refactoring code to ensure maintainability, performance, and scalability. • Participating in technical design discussions and contributing to frontend architecture decisions. • Writing and maintaining technical documentation for components and frontend processes. • Supporting integration with backend services and APIs. You will be the best fit if you have: • 5+ years of experience as a Frontend Developer, with strong expertise in Angular (2+). • Strong understanding of JavaScript / TypeScript, HTML5, and CSS3. • Experience with state management solutions (e.g., NgRx) and component-based architecture. • Experience with RESTful APIs and integration with backend services. • Familiarity with modern frontend tooling (e.g., Webpack, Vite, npm/yarn). • Knowledge of performance optimization techniques and building scalable web applications. • Experience with testing frameworks (e.g., Jasmine, Karma, Cypress or similar). • Knowledge of CI/CD pipelines and version control systems (e.g., Git). • Strong problem-solving skills and attention to detail. • English level B2 or higher. • Experience working in Agile/Scrum teams and contributing to iterative development. • Experience with AI technologies, including using AI tools for development and building AI-powered features or applications. What we offer • Remote work or working from our Bialystok, Warsaw, Rzeszow offices. It's up to you! • Collaboration with experienced and engaged people who will appreciate your work and support you whenever you need it 😊 • Hybrid and flexible cooperation model based on a B2B Framework Agreement. • Great working conditions and best equipment: Dell or MacBook, your choice. Good to know: We don’t require a degree. We don’t do whiteboard puzzles or trick questions. Our interview process is practical: a technical conversation, and a chat about how you work. We value direct communication and intellectual curiosity. If you’re someone who gets excited debugging a tricky concurrency issue - not because you have to, but because you want to understand it — we’ll get along well.

🏢 Summary: Senior Frontend Developer (React) role focused on designing and delivering scalable, high-quality frontend applications using React and Next.js across diverse software projects, including AI-driven and legacy modernization initiatives. The position involves architectural decisions, performance optimization, API integration, and collaboration within cross-functional Agile teams. B2B contract with opportunity to work on production systems at scale. 🗂️ Requirements: 5+ years experience as Frontend Developer, Strong expertise in React, Proficiency in JavaScript, Proficiency in TypeScript, Strong knowledge of HTML5, Strong knowledge of CSS3, Experience with Next.js including SSR and SSG, Experience with state management libraries, Experience integrating RESTful APIs, Familiarity with modern frontend tooling, Experience with testing frameworks, Knowledge of CI/CD pipelines, Proficiency with Git, Experience working in Agile/Scrum, English level B2 or higher 📃 Skills: React, Next.js, JavaScript, TypeScript, HTML5, CSS3, Redux, Zustand, REST, Vite, Webpack, npm, yarn, Jest, ReactTestingLibrary, Cypress, CI/CD, Git, Agile, Scrum, AI 🏢 Description: Who we are: We are Inspeerity (part of DevelopX group), engineering consultancy providing software development and consultancy. Our primary expertise is systems architecture and full stack development – from defining project requirements, to designing, building, and deploying software applications for web, backend, enterprise and mobile. We are crazy about technology, serious about people. About position: We are currently building our talent pool for future Senior Frontend Developer (React) roles. As our company is expanding, you may have the opportunity to work on a variety of software solutions across multiple initiatives, including projects we will be delivering in the future, from building native AI solutions to modernizing legacy systems. If you enjoy collaborating in a skilled team and are committed to delivering top-notch software, we’d love to connect. e're not prescriptive about background. Whether you've worked in fintech, SaaS, e-commerce, or enterprise systems — what matters is that you've shipped production software at scale, cared about its reliability, and learned from what broke. TL;DR • Who: Senior Frontend Developer (React) • Contract Type: B2B Framework Agreement • Salary range: Up to 140 PLN/h • Company: Software House What you’ll be doing: • Designing, implementing, and maintaining high-quality frontend applications using React. • Building modern, responsive user interfaces and reusable components. • Working with frameworks like Next.js to deliver performant, scalable applications (including SSR/SSG when applicable). • Collaborating with cross-functional teams including backend developers, designers, and product stakeholders. • Reviewing and refactoring code to ensure maintainability, performance, and scalability. • Participating in technical design discussions and contributing to frontend architecture decisions. • Writing and maintaining technical documentation for components and frontend processes. • Supporting integration with backend services and APIs. You will be the best fit if you have: • 5+ years of experience as a Frontend Developer, with strong expertise in React. • Strong understanding of JavaScript / TypeScript, HTML5, and CSS3. • Experience building applications with frameworks such as Next.js, including server-side rendering and static generation. • Experience with state management approaches (e.g., Redux, Zustand, or similar). • Experience with RESTful APIs and integration with backend services. • Familiarity with modern frontend tooling (e.g., Vite, Webpack, npm/yarn). • Knowledge of performance optimization techniques and building scalable web applications. • Experience with testing frameworks (e.g., Jest, React Testing Library, Cypress or similar). • Knowledge of CI/CD pipelines and version control systems (e.g., Git). • Strong problem-solving skills and attention to detail. • English level B2 or higher. • Experience working in Agile/Scrum teams and contributing to iterative development. • Experience with AI technologies, including using AI tools for development and building AI-powered features or applications. What we offer • Remote work or working from our Bialystok, Warsaw, Rzeszow offices. It's up to you! • Collaboration with experienced and engaged people who will appreciate your work and support you whenever you need it 😊 • Hybrid and flexible cooperation model based on a B2B Framework Agreement. • Great working conditions and best equipment: Dell or MacBook, your choice. Good to know: We don’t require a degree. We don’t do whiteboard puzzles or trick questions. Our interview process is practical: a technical conversation, and a chat about how you work. We value direct communication and intellectual curiosity. If you’re someone who gets excited debugging a tricky concurrency issue - not because you have to, but because you want to understand it — we’ll get along well.

🏢 Summary: Senior Node.js Developer role focused on building and maintaining distributed backend systems for digital advertising and identity management using Node.js and NestJS. The position involves full lifecycle development, performance optimization, automated testing, and monitoring within a non-monolithic architecture. It also includes contributing to R&D initiatives to evolve the advertising ecosystem. 🗂️ Requirements: Higher education in Computer Science or related field, Minimum 5 years of programming experience, At least 5 years of Node.js development experience, Experience in backend application design, Experience in performance optimization, Experience in application monitoring, Experience with distributed (non-monolithic) architecture, Proficiency in automated testing development, Very good knowledge of Node.js and TypeScript, Very good knowledge of NestJS or Fastify, Experience with MongoDB and Redis, Experience with AWS S3, Knowledge of object-oriented and functional JavaScript, Experience in event-driven development, Knowledge of design patterns and best practices, Experience with Git and GitHub, English proficiency for technical documentation 📃 Skills: Node.js, TypeScript, NestJS, Fastify, MongoDB, Redis, AWS, S3, JavaScript, GIT, GitHub, Babel, Jest, Jasmine, Karma, Cypress, Datadog, Jenkins, Unix, Bash, React, NoSQL 🏢 Description: Shape the Future of Digital Advertising as a Senior Node.js Developer! Krakow/Warsaw-based opportunity with almost fully remote work model (1 day in the office/month). As a Senior Node.js Developer you'll be working for our client, a prominent player in the media industry. You will join the team and take responsibility for the development and maintenance of backend applications (Node.js, NestJS) in the field of digital advertising serving technologies and identity management, built in a distributed (non-monolithic) architecture. We are seeking someone actively engaged in improving the quality of solutions and processes, including the development of automated tests and monitoring tools, as well as co-creating new directions for the development of the advertising ecosystem (R&D). Your main responsibilities: Develop and maintain backend applications (Node.js, NestJS) for digital advertising serving and identity technologies. Develop and maintain automated tests (tools and test cases). Develop and maintain monitoring solutions. Actively participate in creating new solutions and development directions for the advertising ecosystem (R&D). Participate in the full software development lifecycle: from requirements clarification, through design, implementation, deployment, to maintenance and monitoring. You're ideal for this role if you have: Higher education, preferably in Computer Science. Minimum 5 years of programming experience in IT projects. At least 5 years of experience in Node.js project development. Experience in application design, performance optimization, and monitoring. Ability to decompose tasks effectively. Very good knowledge of: Node.js, TypeScript Frameworks such as NestJS, Fastify Databases: MongoDB, Redis AWS S3 bucket Object-oriented and functional programming in JavaScript Event-driven development Design patterns and best practices Version control systems: GIT, GitHub Babel tools Willingness for active professional growth English language skills sufficient for reading/writing technical documentation Nice to have: Knowledge of digital/programmatic advertising Familiarity with React.js and NoSQL databases Comfortable working in Unix environments, including writing bash scripts Experience with Jenkins Familiarity with Agile / Scrum / KANBAN methodologies Experience with Datadog Familiarity with test frameworks like Jest, Jasmine, Karma, Cypress Ability to write unit, functional, and integration tests

🏢 Summary: Senior Node.js Developer role focused on building and maintaining distributed backend systems for digital advertising and identity management. The position involves full lifecycle development, automated testing, monitoring, and performance optimization using Node.js and related technologies. The role is almost fully remote with occasional office presence in Krakow or Warsaw. 🗂️ Requirements: Higher education in Computer Science or related field, Minimum 5 years of programming experience, At least 5 years of commercial experience with Node.js, Strong knowledge of Node.js and TypeScript, Experience with NestJS or Fastify frameworks, Experience with MongoDB and Redis, Experience with AWS and S3, Experience in application design and performance optimization, Experience in building automated tests and monitoring solutions, Knowledge of event-driven architecture and design patterns, Proficiency with Git and GitHub, Good command of technical English 📃 Skills: Node.js, TypeScript, NestJS, Fastify, MongoDB, Redis, AWS, S3, JavaScript, Git, GitHub, Babel 🏢 Description: Shape the Future of Digital Advertising as a Senior Node.js Developer! Krakow/Warsaw-based opportunity with almost fully remote work model (1 day in the office/month). As a Senior Node.js Developer you'll be working for our client, a prominent player in the media industry. You will join the team and take responsibility for the development and maintenance of backend applications (Node.js, NestJS) in the field of digital advertising serving technologies and identity management, built in a distributed (non-monolithic) architecture. We are seeking someone actively engaged in improving the quality of solutions and processes, including the development of automated tests and monitoring tools, as well as co-creating new directions for the development of the advertising ecosystem (R&D). Your main responsibilities: Develop and maintain backend applications (Node.js, NestJS) for digital advertising serving and identity technologies. Develop and maintain automated tests (tools and test cases). Develop and maintain monitoring solutions. Actively participate in creating new solutions and development directions for the advertising ecosystem (R&D). Participate in the full software development lifecycle: from requirements clarification, through design, implementation, deployment, to maintenance and monitoring. You're ideal for this role if you have: Higher education, preferably in Computer Science. Minimum 5 years of programming experience in IT projects. At least 5 years of experience in Node.js project development. Experience in application design, performance optimization, and monitoring. Ability to decompose tasks effectively. Very good knowledge of: Node.js, TypeScript Frameworks such as NestJS, Fastify Databases: MongoDB, Redis AWS S3 bucket Object-oriented and functional programming in JavaScript Event-driven development Design patterns and best practices Version control systems: GIT, GitHub Babel tools Willingness for active professional growth English language skills sufficient for reading/writing technical documentation Nice to have: Knowledge of digital/programmatic advertising Familiarity with React.js and NoSQL databases Comfortable working in Unix environments, including writing bash scripts Experience with Jenkins Familiarity with Agile / Scrum / KANBAN methodologies Experience with Datadog Familiarity with test frameworks like Jest, Jasmine, Karma, Cypress Ability to write unit, functional, and integration tests

🏢 Summary: Senior Full-Stack Developer role focused on building a modern, headless e-commerce and marketing platform using cloud-based, composable architecture. The position involves end-to-end development across backend and frontend, CI/CD automation, and production support within a 12-month B2B contract. The project aims to deliver a fully personalized customer experience in the building materials industry. 🗂️ Requirements: Minimum 4 years experience with DotNet and ASPNETCore, Strong experience with C# and full-stack web development, Experience with SQLServer, Experience with Optimizely, Knowledge of software architecture and design patterns, Experience with CI/CD pipelines, Experience with TDD, Knowledge of web application security and performance principles, Experience with Kafka, Experience with Git and Gitflow 📃 Skills: DotNet, ASPNETCore, C#, SQLServer, Optimizely, Kafka, Webpack, TailwindCSS, Storybook, Chromatic, Rider, VisualStudio, Git, GitHub, Gitflow, React, CICD, TDD 🏢 Description: We are looking for an experienced Senior Full-Stack Developer (with Optimizely) to join the team of our client. The project focuses on building a modern e-commerce and marketing platform based on composable, headless, cloud architecture, with the goal of delivering a seamless and fully personalized end-to-end customer experience. Who we are: We are Inspeerity (part of DevelopX group), a modern software house, providing software development, consultancy, and maintenance services. We specialize in full stack development – from defining project requirements, to designing, building, and deploying software applications for web, backend, enterprise and mobile. We are crazy about technology, serious about people. TL;DR • Who : Senior Full-Stack Developer (with Optimizely) • Contract Type : B2B • Salary range: Up to 210 PLN/h + VAT • Start date : ASAP • Project lenght : ~12 months, with the possibility of extension. • Company : Software House • Project topic : Building Materials Industry What you’ll be doing: Developing scalable technical solutions. Building and maintaining automated build and deployment pipelines. Developing features across the full technology stack, from data access and business logic to the user interface. Writing unit tests, fixing bugs, and preparing documentation. Troubleshooting and resolving production issues. Collaborating closely with business stakeholders to translate requirements into effective technical solutions. You will be the best fit if you have: At least 4 years of practical experience working with Microsoft .NET / ASP. NET Core and SQL Server. Strong understanding of software architecture, design patterns, and engineering best practices. Hands-on experience in full-stack development using C# and web technologies. Solid knowledge of web application performance, quality standards, and security principles. Genuine interest in Generative AI and its application in optimizing and automating the software development lifecycle. Experience working in Agile environments, including CI/CD pipelines, TDD, and peer code reviews. In addition to the stack mentioned above, experience in working with Apache Kafka, Webpack, TailwindCSS, Storybook, Chromatic, Rider, Visual Studio, Git, Github, Gitflow. Experience with React is a plus. English level B2 or higher. What we offer Remote work model with occasional visits to our client's office in Poznań or Warsaw. B2B contract. You’ll join a collaborative team of 12 specialists. About process: Step 1 - Call with with someone from our People Team. Step 2 - Meeting with our .NET Team Lead as a technical interviewer. Step 3 - Final stage. A technical interview with the client-side representatives. Time for your turn! ;)

🏢 Summary: Senior Node.js Developer role focused on building and maintaining backend systems for digital advertising and identity management within a distributed architecture. The position involves full lifecycle development, performance optimization, monitoring, and R&D initiatives in a hybrid or remote model. The role requires strong expertise in Node.js and related technologies to deliver scalable, high-performance solutions. 🗂️ Requirements: Higher education in Computer Science or related field, Minimum 5 years of professional programming experience, Minimum 5 years of hands-on Node.js experience, Strong knowledge of application design and performance optimization, Experience with backend frameworks (NestJS or Fastify), Experience with MongoDB and Redis, Experience with AWS services (including S3), Knowledge of event-driven architecture and design patterns, Experience with Git and GitHub, Experience working in Unix environments and Bash scripting, Good command of English (technical documentation), Communicative Polish, Legal right to work in the European Union 📃 Skills: Node.js, TypeScript, NestJS, Fastify, MongoDB, Redis, AWS, S3, JavaScript, Git, GitHub, Bash, Unix, Babel, OOP, FP, EventDriven, DesignPatterns, Monitoring, Testing, Polish, English 🏢 Description: Unleash the Future of Digital Advertising — Elevate Backend Architectures with Cutting-Edge Node.js Solutions! Krakow/Warsaw-based opportunity with almost fully remote work model (only 1 day in the office/month). As a Senior Node.js Developer , you will be working for our client, a leading innovator in the media industry. You will join a dynamic team dedicated to advancing digital advertising technologies, focusing on backend development and identity management in a distributed, non-monolithic architecture. This role offers a chance to influence the evolution of advertising ecosystems through innovation and R&D initiatives, fostering your professional growth in a fast-paced environment. Your main responsibilities: Develop and maintain backend applications (Node.js, NestJS) for digital advertising serving and identity technologies. Develop and maintain automated tests (tools and test cases). Develop and maintain monitoring solutions to ensure system reliability. Actively participate in creating new solutions and shaping development directions (R&D) within the advertising ecosystem. Participate in the full software development lifecycle: from requirements clarification, through design and implementation, to deployment, maintenance, and monitoring. You're ideal for this role if you have: Minimum of 5 years of programming experience in IT projects. At least 5 years of experience in Node.js project development. Strong knowledge of application design, performance optimization, and system monitoring. Proficiency in Node.js, TypeScript, NestJS, Fastify. Experience with MongoDB, Redis, AWS S3. Ability to decompose tasks effectively and work collaboratively. Good understanding of object-oriented and functional programming in JavaScript. Familiarity with event-driven development, design patterns, and best practices. Experience with version control systems: GIT, GitHub. Knowledge of Babel tools. Willingness for active professional growth. Excellent communicative skills in Polish and sufficient English for reading/writing technical documentation. It is a strong plus if you have: Knowledge of digital/programmatic advertising. Familiarity with React.js and NoSQL databases. Experience working in Unix environments, including writing bash scripts. Hands-on experience with Jenkins. Familiarity with Agile, Scrum, or KANBAN methodologies. Experience with Datadog. Knowledge of test frameworks like Jest, Jasmine, Karma, Cypress. Ability to write unit, functional, and integration tests. Language Required for the role: Communicative proficiency in Polish. English skills sufficient for technical documentation. Eligibility for the role: Only candidates with an existing legal right to work in the European Union will be considered for this role. #MAKEYourCareerBETTER Interested? Apply now and include your CV (preferably in English) along with a statement confirming your consent to the processing and storage of your personal data.

🏢 Summary: Remote Senior Backend Node.js Developer role focused on building and scaling an event-driven microservices trading platform. The position involves end-to-end development, collaborating across product, QA, and DevOps to deliver high-performance, scalable trading solutions. B2B contract with overlap required with NYC working hours. 🗂️ Requirements: Bachelor’s Degree in Computer Science or related field, 3-5 years professional web application development experience, Expert-level Node.js knowledge, Expert-level TypeScript knowledge, Experience with distributed systems, Experience with Apache Kafka, Redis, Kubernetes, MongoDB, Experience with automated unit testing and TDD, Strong understanding of performance optimization and computational complexity, Knowledge of algorithms and design patterns, Fluent English (written and spoken) 📃 Skills: Node.js, TypeScript, Kafka, Redis, Kubernetes, MongoDB, Microservices, TDD, Algorithms, DesignPatterns, Web, DistributedSystems 🏢 Description: We are looking for a performance-driven backend Senior Node.js Developer who can help us bring our client's trading solutions to the next level of functionality, scalability, and user experience. They are actively developing a new event-driven microservices architecture to form a foundational platform for delivering new trading applications. You will be responsible for delivering software end-to-end , from liaising with product managers and designers, to coordinating across international development teams on engineering and architecture to working with QA and DevOps teams - all ultimately to deliver a quality, innovative product to the traders and investors who depend on the platform every day. Requirements: Fluent English language [both written and spoken] Education: at least Bachelor's Degree, preferably in Computer Science 3-5 years' professional web application development experience Expert-level Node.js and TypeScript knowledge, and curiosity to learn more Broad knowledge of web platform and technologies Superior analytical and problem-solving ability Effective communication skills to work with different teams across an international company Experience with modern distributed systems and infrastructure technologies, including Apache Kafka, Redis, Kubernetes, and MongoDB Automated unit testing and test-driven development Robust understanding of performance issues, computational complexity, and code optimization. Familiarity and implementation of industry-standard algorithms and design patterns Proactive and team player who can deliver in a high-pressure demanding environment Nest.js – nice to have Offer details: 100% remote job preferrably at least 4-5 hours overlap with NYC working hours B2B contract rate up to 50 USD/h net Don't hesitate and apply now!

🏢 Summary: Full-time Senior Back-End Engineer (Node.js) role focused on designing and maintaining scalable, high-performance server-side applications and APIs for modern, data-driven platforms. The position involves building RESTful services, integrating with third-party systems, ensuring code quality through testing, and optimizing system reliability and performance. Hybrid work model in Warsaw with B2B or CoE contract options. 🗂️ Requirements: Strong experience with Node.js, Strong experience with Express.js, Experience building and integrating APIs (GraphQL or REST), Knowledge of OAuth, JWT, and session-based authentication, Experience with MySQL, Experience with PostgreSQL, Experience writing unit tests with Chai and Mocha, Experience using Git and version control systems 📃 Skills: Node.js, Express.js, GraphQL, REST, OAuth, JWT, MySQL, PostgreSQL, Chai, Mocha, Git 🏢 Description: Senior Back-End Engineer (Node.js) 💰 Salary: 18,700-20,900 PLN/Month 💻 Warsaw, Poland (Hybrid - 3 days in office, 2 days remote) 🕦 Full-time ☑️ B2B or CoE We’re looking for a Senior Back-End Engineer to join a fast-growing international tech company focused on building modern, data-driven platforms that power digital transformation in the financial and enterprise sectors. Requirements: Strong experience in building server-side applications using Node.js and Express.js. Hands-on experience with API development and integration, particularly with GraphQL or RESTful services. Strong knowledge of authentication and authorization mechanisms (OAuth, JWT, session-based). Strong experience with databases such as MySQL and  PostgreSQL. Experience writing unit tests with tools such as Chai and Mocha. Strong experience using Git and version control systems. Proficiency in English (both written and spoken). Nice To have: Bachelor’s degree in Computer Science or a related field. Experience with cloud platforms (AWS, Azure, or GCP), as well as containerization and orchestration tools such as Docker and Kubernetes. Experience with microservices architecture. Experience setting up CI for static analysis and test execution. Experience developing RAG applications and storing data in vector embeddings. Key Responsibilities: Design, build, and maintain scalable, high-performance server-side applications and RESTful APIs using Node.js and Express.js. Guide and supervise the development of key code components to ensure long-term reliability and scalability. Integrate with front-end components and third-party services. Actively review the codebase, recommending and implementing refinements where needed. Write unit and integration tests and optimize performance to ensure high-quality code. Collaborate closely with cross-functional teams to define and implement technical solutions. Improve system performance, reliability, and long-term maintainability through optimization and best practices. Get to know DevsData: We are a technology consulting company and a recruitment agency, delivering software solutions to clients from Europe and the US. We work 100% remotely, in an international team, including people from Asia, London, or San Francisco. We employ people with experience in international corporations as well as students of the best technical and business universities. Find out more: https://devsdata.com/