Senior Backend Developer at altersolutions | Wrocław

Join our dynamic team at Renmoney as a Java Backend Developer, where you will contribute to our core engineering teams, including Banking, Loans, Core Tech Platform, and Cards. Our teams are focused on developing high-impact, backend-heavy systems that drive essential financial products and internal platforms.At Renmoney, we prioritize engineering excellence—not only in delivery speed but also in system quality and the artistry of software development. We are cultivating a collaborative engineering culture that values clear communication, thoughtful architecture, rigorous testing, and teamwork.Our tech stack includes: Java • Spring Boot • AWS (EKS) • MySQL • Kafka • Redis • Grafana • Prometheus.

Role Overview oscilar is hiring a Senior Backend Engineer with a focus on Java. This remote position is open to candidates based in Poland. The role centers on building and maintaining backend systems that support oscilar’s products and services. What You Will Do Work closely with teams across disciplines to design, implement, and support backend applications Develop scalable, reliable backend systems using Java Contribute to the ongoing improvement of code quality and system performance Location This is a remote role available to candidates located in Poland.

Join our dynamic development team as an experienced Backend Engineer, where you will play a crucial role in building large-scale event-driven systems. We are collaborating with a forward-thinking integrated shipping services company, known for their innovative approach to global logistics. They maintain a smart and efficient worldwide network, providing reliable shipping services that ensure stable operations for customers globally. Your primary responsibilities will include designing and constructing event-driven solutions utilizing Kafka and related technologies, with a strong emphasis on stream processing applications, data pipelines, and monitoring solutions built with the ELK stack.

Join our client, a pioneer in digital identity and fraud prevention solutions, serving banks, fintech firms, online marketplaces, and other regulated industries globally. Their innovative products harmoniously blend biometric identity verification, document and image processing, and sophisticated fraud detection techniques, empowering clients to deliver smooth digital experiences while upholding robust security measures and compliance with regulations. The company harnesses the power of AI, machine learning, and computer vision to enhance identity verification, mobile deposit, and liveness detection solutions utilized by thousands of organizations worldwide.About the RoleWe are in search of a Senior Java Backend Engineer to become a crucial member of our cross-functional team dedicated to developing cloud-native identity and fraud prevention products on AWS. In this pivotal position, you will architect and implement scalable, high-performance backend services and APIs in Java, operating within a microservices and serverless architecture. You will engage in close collaboration with product managers, front-end engineers, researchers, and DevOps specialists to deliver production-ready features that enable real-time identity verification and extensive fraud detection.What You Will DoDesign, develop, deploy, and maintain production-ready backend APIs and microservices in Java, primarily utilizing AWS as the deployment platform.Construct scalable and resilient services leveraging serverless and containerized architectures (ECS, Lambda, API Gateway).Write clean, efficient, and testable code, emphasizing quality engineering and continuous delivery.Design and execute robust automated test suites, including unit, integration, and performance tests.Collaborate with product managers, front-end engineers, QA, and cloud operations teams to translate requirements into well-crafted features.Contribute to the development of CI/CD pipelines and advocate for DevOps best practices to ensure rapid and reliable deployments.Create and maintain both internal software and public API documentation.Participate in Agile ceremonies such as stand-ups, sprint planning, refinements, and retrospectives.Mentor and support junior team members, sharing knowledge to elevate team capabilities.

Join Netguru, a pioneering force in digital commerce, as we assist renowned brands in modernizing their B2B solutions, marketplaces, and retail ecosystems. Since our inception in 2008, we have empowered businesses through innovative technology, AI-driven personalization, and exceptional engineering and design teams. As a certified B Corporation®, we proudly serve major brands such as IKEA, VW, OLX, Delivery Hero, Żabka, Wolt, Careem, and Vinted.We are currently seeking a Senior Backend Engineer with robust architectural expertise to engage in a long-term project for a European client in the laboratory and biotech sector. This position is a single-developer project, requiring close collaboration with the client’s internal teams and laboratory stakeholders to clarify requirements, outline the project scope, and enhance existing backend processes. Strong communication skills are vital, as you will frequently participate in technical discussions with LIMS and laboratory teams. Your role will encompass hands-on development, legacy code refactoring, and contributing to a scalable, well-structured backend architecture. Please note that candidates must be based in the EU due to client stipulations.Position: Senior Backend Engineer (Java / Architecture)Contract: Freelance / B2B – Remote (EU Only)Rate: 36–50 EUR/hourLanguage: English C1Key ResponsibilitiesOperate independently as the sole backend engineer on the project.Refactor and modernize legacy backend systems.Enhance and expand existing microservices and backend integrations.Maintain and develop REST and SOAP interfaces.Engage with laboratory teams and LIMS stakeholders to define requirements.Guarantee stable operation of backend services in an on-premise Kubernetes environment.Work collaboratively with internal client teams to ensure architectural consistency.QualificationsTechnical Skills & ExperienceExtensive experience with Java (Spring / Spring Boot).Strong architectural and problem-solving abilities.Proficient in designing and maintaining REST APIs.Familiarity with SOAP services.Experience in microservices environments.Hands-on experience with Kubernetes (preferably on-premise setups).Background in working with or integrating LIMS systems.Solid understanding of refactoring and modernizing legacy code.Excellent communication skills for direct collaboration with laboratory stakeholders.Proficiency in English at C1 level.Must be based in the European Union.BenefitsIn return, we offer:100% remote, flexible work environment;Access to cutting-edge technology and tools;Opportunities for professional development.

Flying Bisons is a premier Digital Consulting and Delivery company situated in the vibrant city of Warsaw, Poland. Our mission is to empower our clients to Unleash Digital Potential™. We excel in discovering, defining, designing, and developing top-tier digital products that yield impactful business results for our clients, creating outstanding digital experiences for millions worldwide.What sets us apart is our comprehensive end-to-end process that equips us to tackle every challenge with the assurance of achieving optimal results. Our areas of expertise encompass Research, Digital Strategy, Branding, Content Creation (Written, Photos, Videos), Product Design, Web & Mobile Development, Data Analytics, and AI.Become part of our dynamic team of 120 professionals and collaborate in crafting groundbreaking products and exhilarating experiences for notable brands(such as Mercedes AMG, IKEA, KFC, eObuwie, Żabka, Sanofi, Zain) and innovative startups (like Booksy, Nethone, Telemedi, or DevSkiller)!We are in the process of building a curated network of talented freelance Backend Developers to engage for both current and future projects. When you apply to join our freelancer base, your application will be assessed and kept on file. You may not be contacted immediately, but once a project aligns with your expertise, you will receive an invitation to participate, allowing you to accept or decline based on your availability. If you're interested in joining our talent pool, please submit your CV. We will reach out as soon as a fitting opportunity becomes available.Are you a self-motivated and reliable professional? If so, we are eager to hear from you!

About UsXebia is a leading global technology firm that embarked on its journey in Central and Eastern Europe with two renowned Polish companies: PGS Software, celebrated for its premier cloud and software solutions, and GetInData, a trailblazer in Big Data analytics. Today, we are a formidable team of over 1,000 experts committed to delivering exceptional cloud, data, and software solutions, and we are just beginning our exciting journey.Our MissionWe engage in transformative projects that truly matter. From fintech and e-commerce to aviation, logistics, media, and fashion, we empower our clients to create scalable platforms, data-driven insights, and innovative applications that shape the future of technology. Our esteemed clients include industry leaders such as McLaren, Aviva, Deloitte, Spotify, Disney, ING, UPS, Tesco, Truecaller, AllSaints, Volotea, Schmitz Cargobull, Allegro, and InPost, among others.We prioritize intelligent technology, genuine ownership, and continuous personal and professional growth. Our work with modern, open-source stacks, combined with partnerships with Databricks, dbt, Snowflake, Azure, GCP, and AWS, underscores our commitment to excellence. Fun fact: we were the first AWS Premier Partner in Poland!Community and CultureAt Xebia, our community is what makes us unique. We actively support tech communities, host meetups (including Software Talks and Data Tech Talks), and foster a culture that emphasizes individual growth through Guilds, Labs, and dedicated personal development budgets, covering both technical and soft skills. This is more than just a job; it's a space for growth.Why Choose Us?What sets us apart is our mindset, our vibrant culture, and our exceptional people. While it's challenging to fully capture in words, we invite you to visit us and experience it for yourself.Your Role:Lead the design and delivery of intricate backend features and services, from concept to deployment and ongoing maintenance.Develop high-quality, production-ready software using Java and Spring Boot, adhering to architectural standards.Promote technical excellence by implementing best practices, clean architecture principles, and robust testing strategies.Mentor junior developers and contribute to their growth and skill enhancement.

Join Bosch Group as an IT Intern focusing on BackEnd development with Java! This is an exciting opportunity to gain hands-on experience in the tech industry while working with a renowned global leader in technology and services. As an intern, you will collaborate with experienced professionals, enhance your programming skills, and contribute to real-world projects.

Role Overview Software Mind is hiring a Backend Tech Lead (Java) to join the team in Kraków. This role leads a group of backend developers, shaping architecture and guiding the development of backend systems. The Tech Lead makes key technical decisions and helps ensure code quality and timely project completion.

Highlights Location: Fully Remote (CET hours preferred) Compensation: €5,100 - €6,300 per month + stock options Language: Russian-speaking team About Fundraise Up At Fundraise Up, we are revolutionizing the way nonprofits receive donations. Our innovative platform facilitates a fast, seamless, and user-friendly donation experience, empowering organizations to harness the power of generosity. Our technology processes tens of millions of dollars in donations monthly, focusing on enhancements that lead to faster load times, higher conversion rates, and accessible design. Trusted by renowned nonprofits like UNICEF and the Alzheimer’s Association, and with a stellar 4.9/5 rating on leading software review platforms, our product is recognized for both its effectiveness and quality. A Truly Global Product We serve nonprofit organizations across North America, the UK, Australia, and Europe in the enterprise sector. Our robust product ecosystem includes a modern checkout experience, customizable widgets, donor and organization portals, admin tools, and multiple internal applications. Our backend technology stack features Node.js (Koa, NestJS) and MongoDB. The frontend utilizes Webpack, Vue.js, and React, with a significant portion of the codebase written in TypeScript. For high-volume messaging and background processing, we implement Kafka and Bull (Redis). Analytics are managed through ClickHouse, while Elasticsearch is utilized for search functionalities. The Team We are a diverse team of over 160 professionals, including more than 80 engineers, distributed across Spain, Poland, Portugal, Georgia, Armenia, Serbia, Turkey, and Cyprus. Our team members typically possess 5-10+ years of experience, fostering a culture of technical curiosity and knowledge sharing. Despite our size, we maintain a close-knit team environment where every contribution is valued, and collaboration is key. We prioritize strong engineering practices and a product-first mindset, hosting biweekly engineering forums to share insights and celebrate achievements. Join a team where quality, mentorship, and mutual respect are at the forefront. About the Role As a Backend Developer, you will be instrumental in architecting the core engine that drives our global platform. You will tackle complex challenges within a high-load, distributed system, constructing and scaling the infrastructure that processes millions in donations. This role goes beyond maintenance; it involves active development and innovation.

Endava seeks a Senior Java Developer based in Krakow to join teams working on client software projects. This position centers on hands-on Java development and close cooperation with colleagues from various backgrounds. Role overview The Senior Java Developer will build and maintain reliable Java applications. The work involves designing solutions, writing code, and ensuring software meets client needs. Collaboration with cross-functional teams is a core part of the job. What you will do Design, develop, and maintain Java applications Work with teams across disciplines to deliver software that matches client requirements Share technical expertise to help improve project outcomes and efficiency Requirements Solid experience working with Java Ability to collaborate effectively in a team Dedication to delivering high-quality software

Join our innovative team at dev2 as a Backend Software Engineer where you will play a crucial role in developing scalable backend solutions. Your expertise will help shape our technology stack and improve system performance. You will collaborate with cross-functional teams to design, implement, and maintain high-quality applications.

Join Turnitin as a Senior Fullstack/Backend Software Engineer, where your expertise in backend development, particularly with Java and serverless architectures, will be pivotal. We are seeking engineers who are enthusiastic about creating scalable distributed systems and delivering robust software solutions for our acclaimed educational platform.As an integral member of our shared services team, you'll spearhead the development and enhancement of the core systems supporting both our existing and upcoming applications.Key Responsibilities:Architect, develop, and optimize scalable backend services utilizing Java and serverless technologies (AWS Lambda).Design and implement RESTful APIs and event-driven architectures.Contribute to frontend component development as required.Enhance performance and cost-effectiveness of existing services.Collaborate with cross-functional teams, including Architects, Product Managers, and engineering leads, to deliver innovative solutions.Mentor junior developers and promote best practices.Establish and manage CI/CD pipelines.Maintain high-quality coding standards through peer reviews, automated testing, and compliance with development best practices.Document shared components comprehensively, providing usage guidelines and examples.

About Our Team At SumUp, we provide a comprehensive Point-of-Sale (POS) solution designed to empower businesses such as cafes, shops, bars, and salons to streamline operations and foster growth. Our platform encompasses a variety of features including product catalogs, inventory management, business analytics, compliance assistance, and loyalty programs. The Fiscalization team is dedicated to ensuring compliance in countries like Italy, Sweden, Norway, Belgium, and Austria, among others. We are also pioneering the integration with third-party services for fiscalizing receipts. As a Senior Backend Engineer, you will work alongside a vibrant, cross-functional team comprising Product Managers, Designers, Engineering Managers, and fellow engineers. Your Role In this position, you will develop secure backend systems that ensure SumUp's POS products are compliant across various countries on our roadmap. You will collaborate with the Fiscalization squad to devise unique solutions tailored to the challenges in each market. We are looking for a developer who values user-centric design, precision, and seamless collaboration. You will excel in a structured communication environment and thrive in a cross-functional team. This is a B2B role based in Warsaw. Key Responsibilities Design and maintain fiscal compliance solutions to support SumUp's expansion across Italy, Sweden, Norway, Belgium, Austria, and other European markets. Develop integrations with third-party services for receipt fiscalization and regulatory reporting. Navigate SumUp's intricate POS ecosystem and familiarize yourself with fiscalization frameworks across multiple jurisdictions. Work collaboratively with team members and stakeholders distributed across 5+ cities in a hybrid working model. You Will Succeed in This Role If You Have: 5+ years of experience in backend engineering with expertise in Java and/or Kotlin. A solid understanding of system architecture, design principles, data modeling, and API development. Hands-on experience with distributed and fault-tolerant systems. Proficiency in AWS and Kubernetes. Strong knowledge of Kafka, PostgreSQL, and CQRS.

Role Overview Endava is looking for a Senior Java Developer in Gdansk. This role focuses on building and refining software solutions for clients. The position involves designing, implementing, and improving complex Java applications. What You Will Do Design and develop Java-based applications Optimize existing systems for better performance and reliability Work closely with colleagues from different disciplines to integrate solutions

Join the ARQ Team!At ARQ, we are revolutionizing the fintech landscape. Our aim is to transform global financial interactions, creating a seamless infrastructure for value transfer across borders. As we embark on this exciting journey, every new team member plays a crucial role in shaping our innovative products, company culture, and future growth. If you are passionate about tackling significant challenges and making a global impact while being part of a talented team, ARQ is the perfect place for you!Your RoleAs a Backend Engineer, you will be responsible for designing, developing, and maintaining robust backend systems that support our cutting-edge financial products. You'll work closely with a skilled team to craft solutions that promote financial inclusion and help users manage their finances more effectively.Key ResponsibilitiesFocus on developing new systems as well as enhancing existing ones.Engage in projects including building REST APIs, creating microservices, and evolving essential systems like card payments, treasury management, and cryptocurrency liquidity.Utilize Java 25 for backend development alongside a PostgreSQL database.Leverage Spring Boot to ensure quick and efficient delivery of solutions.Adopt a pragmatic approach to developing business logic, focusing on writing clean, maintainable code, and employing methodologies like TDD, DDD, and continuous integration and delivery.QualificationsA minimum of 5 years of experience in backend development with a strong command of Java.A Bachelor's degree or higher in Computer Science, Mathematics, Physics, or related engineering/science fields.A quick learner with a driven, results-oriented mindset and exceptional communication skills (fluent in English, both verbal and written).Proven experience in developing complex products utilized by millions in high-growth startup environments.

Join Our Team at HSP GroupHSP Group stands at the forefront of global expansion services, dedicated to simplifying the complexities of international operations. We offer a comprehensive suite of solutions in legal entity setup, global HR, payroll, compliance, tax, and advisory, empowering our clients to scale efficiently while minimizing risks.As a pioneering startup in the dynamic field of global expansion management, we pride ourselves on our commitment to innovation, delivery excellence, and customer satisfaction. You will be an integral part of our small yet highly skilled team, contributing directly to our success.About Gateway HRGateway HR is our specialized HRIS platform tailored for global expansion management, featuring seamless integration with our flagship Gateway GXM platform. This enables functionalities such as automated payslip generation, smart contract management, and effortless cross-border compliance.Our ecosystem already incorporates AI-driven document recognition and serverless architecture on Azure, alongside a diverse range of integrated tools for HR, entity management, and compliance.Your RoleThis is a fully remote role. We are seeking a Lead Backend Engineer to spearhead the technical vision for Gateway HR and enhance its integration with GXM. You will engage in hands-on platform development while leading external development teams—refining the architecture, innovating new features, and upholding HSP's engineering standards across the codebase.This position is not solely managerial; you will actively code, review pull requests, challenge architectural choices, and launch features while setting high standards for the team.

Join our dynamic team at Talan as a Senior Java Developer specializing in e-Trading solutions. We are seeking innovative and experienced developers who are passionate about building high-performance trading platforms. You will work closely with cross-functional teams to design, develop, and optimize our trading applications.As a Senior Java Developer, you will leverage your expertise in Java technologies, agile methodologies, and your understanding of financial markets to deliver robust and scalable solutions.

Jobgether is hiring a Senior Node.js Backend Developer in Poland for a partner company. This role joins an experienced engineering team focused on building secure, scalable backend systems that power digital financial services worldwide. Key Responsibilities Design and develop backend solutions with Node.js for global financial products Build and maintain mission-critical services and APIs supporting real-time transactions Architect infrastructure for distributed systems to ensure reliability Optimize backend performance while maintaining strong security standards Collaborate with engineers across different regions Contribute to advancing next-generation financial technology Requirements Proven experience in backend architecture and distributed systems Advanced skills in Node.js development Ability to tackle complex technical challenges Interest in scaling secure, real-time applications Self-motivated and comfortable working with autonomy in a remote-first environment Located in Poland Work Environment This is a remote-first position. The team emphasizes independence, responsibility, and continuous learning. Senior Node.js Backend Developers here work closely with talented colleagues and play a direct role in shaping products used by customers around the world.