Senior Fullstack Software Engineer

🏢 Summary: Full-time Full Stack Software Engineer role focused on building AI-powered enterprise platforms using Java and React in a hybrid Warsaw setup. The position involves developing responsive front-end applications and scalable microservices-based back-end systems, integrating cloud services, and maintaining CI/CD pipelines. Long-term employment contract with emphasis on high-performance, secure, and maintainable solutions. 🗂️ Requirements: 5+ years experience as Full Stack Developer with Java and React.js, Strong proficiency in React.js and Redux, Strong knowledge of TypeScript, HTML5, CSS3, ES6+, Experience with state management and component-based architecture, Experience with UI libraries (Material-UI, Bootstrap, or Tailwind), Strong expertise in Java, Spring Boot, Hibernate, JPA, Experience building RESTful APIs and microservices, Knowledge of OAuth2, JWT, and session-based authentication, Experience with PostgreSQL or MySQL, Experience with MongoDB or Redis, Hands-on experience with CI/CD tools, Experience with AWS, Azure, or GCP, Experience with Docker and Kubernetes, Bachelor’s or Master’s degree in Computer Science or related field, Experience working in Agile environments 📃 Skills: Java, React, Redux, TypeScript, HTML5, CSS3, JavaScript, Spring, SpringBoot, Hibernate, JPA, REST, Microservices, OAuth2, JWT, PostgreSQL, MySQL, MongoDB, Redis, Jenkins, GitHub, GitLab, AWS, Azure, GCP, Docker, Kubernetes 🏢 Description: 💰 Salary: 21,000-22,000 PLN/month 🌎 Hybrid from Warsaw, Poland 🕦 Full-time position, long-term ☑️ Contract of Employment We are looking for a Software Engineer to join our client, a technology company that builds AI-powered platforms and consulting solutions for enterprise operations, with a strong focus on the private capital sector. The company has over ten years of experience working with high-growth and PE-backed businesses, combining deep domain expertise with advanced technology to drive measurable results. Requirements: 5+ years of professional experience as a Full Stack Developer working with Java and React.js. Strong proficiency in React.js, Redux, TypeScript, HTML5, CSS3, and modern JavaScript (ES6+). In-depth understanding of state management solutions and component-based design principles. Experience working with UI libraries/frameworks such as Material-UI, Bootstrap, or Tailwind CSS. Solid expertise in Java, Spring Boot, Hibernate, JPA, and building RESTful APIs. Experience designing and working with microservices architecture and API Gateway patterns. Knowledge of authentication and authorization approaches, including OAuth2, JWT, and session-based methods. Experience with relational databases (PostgreSQL, MySQL) as well as NoSQL solutions (MongoDB, Redis). Hands-on experience using CI/CD tools like Jenkins, GitHub Actions, or GitLab CI/CD. Familiarity with cloud platforms such as AWS, Azure, or GCP, along with containerization tools like Docker and Kubernetes. Bachelor’s or Master’s degree in Computer Science, Engineering, or a related discipline. Experience operating within Agile development environments. Strong analytical thinking and problem-solving abilities. Key Responsibilities: Build and develop dynamic, responsive, and high-performing user interface components using React.js, Redux, and modern JavaScript (ES6+). Ensure applications function consistently across different browsers while delivering a smooth user experience. Enhance front-end performance and apply best practices in UI/UX design. Design, develop, and maintain RESTful APIs and microservices using Java technologies such as Spring Boot, Hibernate, and JPA. Implement secure authentication, authorization, and effective data management solutions. Work with both relational and NoSQL databases, including PostgreSQL, MySQL, and MongoDB. Integrate external services, APIs, and cloud-based platforms into applications. Oversee deployment processes using CI/CD pipelines and containerization technologies like Docker and Kubernetes. Produce clean, efficient, and maintainable code in line with established best practices. Develop and maintain unit and integration tests for both front-end and back-end systems. Collaborate closely with UI/UX designers, product managers, and DevOps specialists. Take part in Agile/Scrum processes and support ongoing improvements to development workflows.

🏢 Summary: Senior Java Software Engineer role focused on architecting and developing scalable SaaS applications for AI-powered data analysis and compliance platforms. The position involves leading technical design, driving best practices, and improving CI/CD and platform quality. The engineer will work across the stack, aligning technical solutions with business needs and ensuring high software quality. 🗂️ Requirements: 5+ years of professional software development experience, 2+ years of experience delivering SaaS products, Proficiency in Java and at least one other language (Python or C#), Strong knowledge of algorithms, data structures, and computational complexity, Experience leading technical design and guiding development teams, Hands-on experience with at least two DevOps platforms: GitHub, Azure DevOps, GitLab, or Jenkins, Experience with CI/CD tooling and developer productivity practices, Ability to design technical solutions from specifications, Experience implementing redundancy and disaster recovery scenarios 📃 Skills: Java, Python, C#, SaaS, Algorithms, DataStructures, GitHub, AzureDevOps, GitLab, Jenkins, CICD, DevOps 🏢 Description: Position: Senior Java Software Engineer Salary: up to 26 000 PLN Form of employment: contract of employment Join our client, which makes software to help users organize data, discover the truth, and act on it. Their SaaS product manages large volumes of data and quickly identifies key issues during litigation and internal investigations. The AI-powered communication surveillance product proactively detects regulatory misconduct like insider trading, collusion, and other non-compliant behavior. They have more than 300,000 users in 49 countries serving thousands of organizations globally. Responsibilities: Architect, design, and develop model-based applications Guide product improvements across schema, framework, and platform Lead the team to best-practice technical design, by example and through collaboration Understand department-wide initiatives and guidelines, work with teams to ensure implementation is aligned with Engineering-wide policies and direction Maintain a backlog of tools or technology enhancements to improve the maintainability and quality of the solutions Encourage teams to work collaboratively by advising and enforcing best practices when needed Stay up-to-date with technologies and best practices related to CI/CD tooling and developer productivity Qualifications: 2+ years of professional experience delivering successful SaaS products. 5+ years of professional experience in software development Strong computer science fundamentals in algorithms, data structures, and computational complexity A self-starter driven to make an impact Strong communication skills, experience leading teams Proficiency in multiple programming languages, e.g, Java, Python, C# Able to learn at multiple levels of the stack – from fine-grained technical implementation to high-level control and data-flow. Comfortable working from Specifications to create a Technical Approach and scoping work Able to consider the Engineering solution in the business context Obsession with software quality and empathy for customer experience In-depth technical understanding and experience with at least two of the following DevOps Platforms: GitHub, Azure DevOps, GitLab, and Jenkins Experience implementing redundancy and disaster recovery scenarios Nice to have: Experience building AI-powered products that use Natural Language Processing or Machine Learning Knowledge of Linux Knowledge of NoSQL database systems such as MongoDB, Redis, and Elasticsearch Fundamental knowledge of Kubernetes and container-based systems Benefits: Comprehensive health, dental, and vision plans Parental leave for primary and secondary caregivers Flexible work arrangements Two, week-long company breaks per year Additional time off Long-term incentive program Training investment program

🏢 Summary: Software Engineer role in a long-term international project, working in a cross-functional team responsible for full product lifecycle from design to production support. The position involves backend and frontend development using modern technologies in an iterative delivery model. Hybrid work model with 5 days per month in the office. 🗂️ Requirements: Minimum 5 years of commercial software development experience, Experience with at least one programming language: Kotlin, Python, or JavaScript, Willingness to work across backend and frontend technologies, Working knowledge of Unix/Linux environments, Understanding of databases: MongoDB, Redis, PostgreSQL, Experience with HTTP APIs and RESTful services, Ability to provide production support and troubleshoot performance and security issues, Good English communication skills 📃 Skills: Kotlin, Python, JavaScript, Unix, Linux, MongoDB, Redis, PostgreSQL, REST, HTTP, .NET, C# 🏢 Description: Software Engineer (Kotlin / Python / JavaScript) Location: Kraków or Warsaw (hybrid — 5 days per month in the office) Contract type: B2B — 130–140 PLN/h Project: Long-term international project About the Role We are looking for a Software Engineer to join a collaborative product team working in an iterative delivery model. The team is responsible for the full lifecycle of the product — from design and development to production support — following the principle: “you build it, you support it.” This role offers an opportunity to work with modern technologies across backend and frontend, while continuously learning new programming languages and tools. Key Responsibilities Work in a cross-functional team of 4–6 engineers Break down requirements into user stories and deliver iteratively to production Design technical solutions aligned with architectural guidelines Provide production support, including troubleshooting bugs, performance, and security issues Identify and manage technical debt alongside new feature development Collaborate closely with team members, including pair programming Ensure high quality and maintainability of delivered solutions Requirements Minimum 5 years of relevant commercial experience Experience with at least one programming language (Kotlin, Python, or JavaScript preferred) Willingness to learn multiple technologies across backend and frontend Working knowledge of Unix/Linux environments Understanding of databases from a usage perspective (MongoDB, Redis, PostgreSQL) Experience with HTTP APIs (RESTful services) Good English communication skills (team communication in English) Nice to Have Knowledge of .NET / C# What We Offer Hybrid work model — only 5 days per month from the office (Kraków or Warsaw) Private medical care (Medicover) Sports card (Multisport or equivalent) Life insurance Long-term, stable cooperation Opportunity to work with modern technologies in an international environment Support for professional development and learning

🏢 Summary: Full-time hybrid Software Engineer role focused on building responsive, AI-driven web applications for enterprise platforms using modern JavaScript technologies. The position involves developing high-quality React-based interfaces, applying TDD and CI practices, and collaborating within cross-functional Agile teams. Long-term B2B contract based in Warsaw with competitive salary. 🗂️ Requirements: 6+ years experience with JavaScript, 6+ years experience with TypeScript, Strong knowledge of design patterns in JavaScript, Proficiency in React with Redux, Experience with Next.js, Understanding of functional programming concepts, Strong knowledge of asynchronous programming, Experience with Git and branch management, Experience debugging front-end applications, Experience creating and integrating custom packages, Understanding of object-oriented programming principles, Practical experience with HTML5, Practical experience with CSS3, Experience in Agile environments, Ability to develop cross-browser compatible code 📃 Skills: JavaScript, TypeScript, React, Redux, Next.js, HTML5, CSS3, Git, TDD, CI, Agile 🏢 Description: 💰 Salary: 14,500-17,000 PLN/month 🌎 Hybrid from Warsaw, Poland 🕦 Full-time position, long-term ☑️ B2B We are looking for a Software Engineer to join our client, a technology company that builds AI-powered platforms and consulting solutions for enterprise operations, with a strong focus on the private capital sector. The company has over ten years of experience working with high-growth and PE-backed businesses, combining deep domain expertise with advanced technology to drive measurable results. Requirements: 6+ years of experience working with JavaScript and TypeScript Solid understanding of design patterns and how to apply them in JavaScript development. Proficiency in a modern front-end JavaScript framework such as React.js with Redux; experience with Next.js is an advantage. Familiarity with functional programming concepts. Strong grasp of asynchronous programming and its best practices. Knowledge of Git and experience with branch management. Experience troubleshooting front-end issues and using relevant debugging tools. Familiarity with creating and integrating custom packages. Good understanding of object-oriented programming principles and their use in JavaScript. Ability to perform effectively under pressure and meet strict deadlines. Practical experience with HTML5 and CSS3. Experience working within Agile development environments and practices. Strong communication and organizational abilities. Skilled in developing cross-browser compatible code. A Bachelor’s degree in Computer Science or a related field is preferred. Key Responsibilities: Creating and building responsive user interfaces using React. Applying and maintaining test-driven development (TDD) practices along with continuous integration processes. Working closely with a cross-functional team that includes project managers, analysts, and sales representatives to deliver high-quality, interactive products within deadlines. Promoting and implementing best practices in testing, accessibility, and performance optimization. Partnering with design, backend, QA, and product teams to develop reliable, user-focused solutions.

🏢 Summary: Mid-level Full-Stack Developer role focused on building and modernizing a cloud-based practice management and CRM platform. The position involves a 60/40 split between Angular frontend and Node.js/Nest.js backend, contributing to migration from monolith to microservices and upgrading to the latest Angular version. Fully remote (Poland-based) with strong impact on architecture and product quality. 🗂️ Requirements: 2–3 years of commercial experience in full-stack web development, Commercial experience or strong willingness to work with Angular, Experience with Node.js backend development, Practical knowledge of Nest.js, Basic knowledge of SQL, Experience or willingness to implement automated E2E tests, Polish residency, Working proficiency in Polish, Notice period of 1 month or less 📃 Skills: Angular, Node.js, Nest.js, SQL, Playwright, Microservices, Cloud, ORM, E2E 🏢 Description: Position: Full-Stack Developer Location: Remote (Poland-based) Salary: 14500 – 19500 PLN / month Our client is an innovative software company delivering a modern, cloud-based practice management and CRM solution dedicated to professional services. The platform streamlines day-to-day operations, including workload management and automated document generation. The development team is highly autonomous, focused on refactoring their core product from a monolith into scalable microservices, migrating to the newest technology stacks, and fostering an environment with strong developer ownership. We are looking for a mid-level Full-Stack Developer (approx. 2–3 years of commercial experience) to join a tight-knit Polish development team. In this role, you will work on both frontend and backend tasks (approx. 60% Front-End and 40% Back-End workload), having a real impact on technology choices and product quality. Requirements: Around 2–3 years of commercial experience in full-stack web development. Professional experience or strong openness to working with Angular (the project is currently on Angular 6 and undergoing a migration to the latest stable version). Solid knowledge of backend development using Node.js, preferably with Nest.js (used for all new microservices). Basic understanding of SQL (complex queries are supported by in-house ORM and AI tools, backed by thorough code reviews). Familiarity with or interest in testing practices (manual testing with beta users and expanding automated E2E tests using Playwright ). Polish residency and working proficiency in Polish (mandatory for active participation in daily sync meetings). Notice period of 1 month or less . Mindset focused on autonomy, taking ownership of tasks, and willingness to challenge the status quo. Responsibilities: Developing new features and maintaining the cloud-based platform (60% FE / 40% BE split). Actively participating in architecture modernization (refactoring the monolith into microservices and migrating the legacy frontend to the latest Angular version). Writing clean, maintainable code and participating in peer code reviews. Ensuring software quality through self-testing and implementing automated E2E test scenarios with Playwright. Onboarding smoothly into the codebase (handling smaller bug fixes and minor features in Month 1, progressing to designing and delivering a major complex feature by Month 3). Attending daily team synchronization meetings (at 10:00 AM Polish time). Offer: Salary: 14500 – 19500 PLN / month (depending on experience). Contract type: Long-term B2B Contract (open to both permanent-like cooperation and 12-month fixed contracts). Working model: 100% Fully Remote work. Flexible working hours (with core presence during the 10:00 AM daily sync). Hardware: Company-provided laptop and necessary equipment. No on-call duties or weekend shifts. Great culture: High levels of engineering autonomy, flat structure, and direct impact on the final product. Fast recruitment process: 3 stages (1h Live Coding data processing task $\rightarrow$ ~3h Homework assignment $\rightarrow$ 1h final CTO interview) with rapid feedback provided within 1–2 business days after each stage.

🏢 Summary: Full-time Senior Full Stack Developer role focused on building scalable, data-driven platforms for financial and enterprise sectors using Node.js and React. The position involves designing microservices, developing RESTful APIs, and creating responsive front-end applications in a hybrid work model (Warsaw). 🗂️ Requirements: 5+ years experience as Senior Full Stack Developer, Strong expertise in Node.js, Strong expertise in React, Experience with Express.js, Experience building RESTful or GraphQL APIs, Knowledge of OAuth and JWT authentication, Proficiency in Redux, HTML5, CSS3, ES6+, Experience with Vite, Webpack or Babel, Experience with MySQL or PostgreSQL, Experience with AWS, Azure or GCP, Experience with Docker and Kubernetes, Proficiency with Git 📃 Skills: Node.js, React, Express.js, GraphQL, REST, OAuth, JWT, Redux, HTML5, CSS3, JavaScript, ES6, Vite, Webpack, Babel, MySQL, PostgreSQL, AWS, Azure, GCP, Docker, Kubernetes, Git, SQL, MongoDB, CI/CD 🏢 Description: Senior Full Stack Developer (Node.js + React) 💰 Salary: 23,000-24,800 PLN/Month 💻 Warsaw, Poland (Hybrid - 3 days in office, 2 days remote) 🕦 Full-time ☑️ B2B or CoE We’re looking for a Senior Full-Stack Developer 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: 5+ years of experience as a Senior Full Stack Developer with significant expertise in Node.js and React. 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). Front-end proficiency in React.js, Redux, HTML5, CSS3, and modern JavaScript (ES6+). Familiarity with front-end build tools such as Vite, Webpack, and Babel. Strong experience with databases such as MySQL and  PostgreSQL. Experience with cloud platforms (AWS, Azure, or GCP), as well as containerization and orchestration tools such as Docker and Kubernetes. Strong experience using Git and version control systems. Proficiency in English (both written and spoken). Key Responsibilities: Design, build, and maintain scalable, high-performance server-side applications and RESTful APIs using Node.js and Express.js. Develop and maintain interactive, responsive user interfaces using React.js, Redux, and modern JavaScript (ES6+). Lead the design and implementation of scalable architectures and microservices. Work closely with database engineers to design efficient schemas and manage data interactions using SQL databases or MongoDB. Ensure reliable deployments and smooth release of updates using CI/CD pipelines and Docker. 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/

🏢 Summary: Senior Software Engineer role focused on building a real-time AI platform, owning features end-to-end across frontend, backend, and cloud infrastructure. The position involves developing full-stack solutions and contributing to technical architecture in a remote-first startup environment. 🗂️ Requirements: Strong experience with TypeScript, Strong experience with React, Hands-on experience with AWS, Experience with Docker, Experience with Linux, Experience with Git, Fluent English 📃 Skills: TypeScript, React, AWS, Docker, Linux, Git, Express, Tailwind, WebSockets, LangChain 🏢 Description: 💰 Salary: 25 000 – 28 000 PLN net/month (B2B) + 26 days paid annual leave + equity (ESOP) 📍 Location: Remote (Poland) + meetup in Poznań once per month Our client is an early-stage startup building a real-time AI platform that supports professionals during live conversations. The system processes interactions in real time and delivers contextual insights, knowledge, and guidance while conversations are happening. The founding team has strong experience in distributed systems, AI platforms, and enterprise SaaS and is currently expanding the engineering team to accelerate product development. Role The client is looking for a Senior Software Engineer who enjoys owning features end-to-end, from frontend interfaces to backend services and cloud infrastructure. You will work closely with the founding team on building a real-time AI-powered product , contributing to both product development and technical architecture. Responsibilities Build full-stack features using TypeScript Develop React-based user interfaces Design and maintain backend services and APIs Work with AWS cloud infrastructure Build and run Docker-based services Improve performance and reliability of real-time systems Requirements Strong experience with TypeScript and React Hands-on experience with AWS Experience with Docker and Linux Comfortable working with Git workflows Fluent English Experience working in remote teams Nice to Have Express Tailwind CSS Experience with real-time systems Knowledge of WebSockets / streaming Experience with LLM frameworks (e.g. LangChain) What the Client Offers Opportunity to build a product from an early stage Direct influence on architecture and product direction Work with experienced founders Remote-first environment Competitive salary + equity High level of ownership and autonomy

🏢 Summary: Full-time Team Lead Software Engineer role focused on leading a full-stack team building high-performance web applications using React and Node.js. The position combines hands-on development with architectural ownership, mentoring, and delivery of scalable, AI-powered enterprise platforms. Work involves designing microservices, APIs, and cloud-based containerized deployments in a hybrid setup from Warsaw. 🗂️ Requirements: 7+ years full-stack experience with React.js and Node.js in production, 2+ years in Team Lead or senior engineering leadership role, Strong knowledge of React ecosystem (Redux, Hooks, component architecture, performance optimization), Proficiency in HTML5, CSS3, JavaScript ES6+, Experience with build tools (Webpack, Vite, or Babel), Experience with Express.js and RESTful API design, Knowledge of OAuth, JWT, session-based authentication, Experience with PostgreSQL or MySQL, Experience with MongoDB or other NoSQL databases, Hands-on experience with Docker, Familiarity with AWS or other major cloud platform, Experience with Git and Agile/Scrum methodologies 📃 Skills: React, Redux, JavaScript, HTML5, CSS3, Node.js, Express, REST, GraphQL, OAuth, JWT, PostgreSQL, MySQL, MongoDB, Docker, Kubernetes, AWS, Git, Webpack, Vite, Babel, Agile, Scrum 🏢 Description: 💰 Salary: 29,500–33,200 PLN/month 🌎 Hybrid from Warsaw, Poland 🕦 Full-time position, long-term ☑️ Contract of Employment We are looking for a Team Lead Software Engineer to join our client, a technology company that builds AI-powered platforms and consulting solutions for enterprise operations, with a strong focus on the private capital sector. The company has over ten years of experience working with high-growth and PE-backed businesses, combining deep domain expertise with advanced technology to drive measurable results. In this role, the focus will be on leading a team of developers across front-end and back-end development, owning architectural decisions, and contributing directly to the codebase. You will mentor engineers and drive the delivery of high-performance web applications using React and Node.js. Requirements 7+ years of full-stack development experience with React.js and Node.js in production environments 2+ years in a team lead, tech lead, or senior engineering leadership role Strong command of the React ecosystem: Redux, React Hooks, component architecture, and performance optimization Solid HTML5, CSS3, and modern JavaScript (ES6+); experience with build tooling such as Webpack, Vite, or Babel Proficiency with Express.js and API design (RESTful; GraphQL is a plus) Working knowledge of auth patterns: OAuth, JWT, session-based authentication Hands-on experience with PostgreSQL or MySQL; familiarity with MongoDB or similar NoSQL databases Docker experience required; Kubernetes is a plus Familiarity with at least one major cloud platform (AWS preferred) Comfortable with Git workflows and Agile/Scrum delivery Responsibilities Lead and mentor a team of software engineers; run code reviews, set engineering standards, and hold the bar on quality Architect and build full-stack features using React.js (with Redux and Hooks) on the front end and Node.js / Express.js on the back end Design scalable microservices and RESTful (or GraphQL) APIs aligned with product requirements Own the testing strategy: define coverage expectations, enforce unit and integration testing, and integrate quality gates into CI/CD pipelines Manage containerized deployments via Docker; collaborate on infrastructure with cloud platforms (AWS, Azure, or GCP) Partner directly with Product and Design to translate requirements into production-grade, accessible interfaces Model and maintain SQL and NoSQL data schemas; own data interaction patterns across services Monitor production systems, triage incidents, and drive root-cause resolution Keep technical documentation accurate and up to date 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. We employ people with experience in international corporations as well as the ones from the best technical and business universities. Find out more: https://devsdata.com

🏢 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/

🏢 Summary: Full Stack Engineer role focused on building and owning integrations between enterprise HR systems and third-party SaaS platforms in a cloud-native environment. The position involves backend-heavy development, API design, CI/CD implementation, and collaboration with HR, Finance, and security teams. Hybrid work model in Warsaw with competitive monthly salary. 🗂️ Requirements: 5+ years of software engineering experience, Experience with SaaS HR software integrations, Knowledge of backend programming languages, Knowledge of JavaScript or TypeScript, Experience designing and implementing RESTful APIs, Experience integrating third-party web services, Knowledge of OAuth2, OIDC, SAML and SSO, Experience with AWS or another major cloud platform, Experience with Git, Experience with CI/CD pipelines, Experience with Terraform, Frontend development experience, Experience gathering and managing requirements, Fluent English 📃 Skills: Java, Python, JavaScript, TypeScript, REST, SOAP, OAuth2, OIDC, SAML, SSO, AWS, Git, CI/CD, Terraform, API 🏢 Description: For our client, an international financial company, we are looking for: Full Stack Engineer, HR Enterprise Systems Location: Warsaw, Poland (3 days in office per week) Salary: 28 000 – 38 000 PLN gross / month (employment) Tasks: - Build and own integrations between enterprise systems and third-party HR SaaS platforms (70% backend, 30% frontend) - Lead end-to-end technical delivery of integration projects - Design and implement robust RESTful APIs and web service adapters that handle both modern REST and legacy SOAP interfaces - Partner with HR, Talent Acquisition, Finance and other corporate teams to gather and manage requirements - Act as the cloud-native integration owner with security and compliance teams - Implement and maintain CI/CD pipelines, automated tests and monitoring Requirements: - 5+ years of experience in software engineering (development & design) - Hands-on experience in SaaS HR software integration (preferably in-house) - Knowledge of one of major backend languages and also JavaScript or TypeScript (preferred stack: Java, Python, JS) - Proven experience designing and implementing RESTful APIs and integrating third-party web services - Experience with authentication and authorization standards (OAuth2, OIDC, SAML and SSO) - Experience building and operating services on a major cloud platform (AWS preferred) - Experience with Git, CI/CD and IaC (Terraform) - Some experience with frontend development - Some experience in gathering and managing requirements (liaising with stakeholders) - Fluent in English