Senior Kotlin / Java Software Engineer - Client Technology (m/f/x)

About Us Join our dynamic international team at Doctolib, based in Berlin, where we are devoted to enhancing the performance, features, and design of our essential healthcare product, the Scheduling System. Over the past decade, Doctolib has experienced remarkable growth by prioritizing pragmatic solutions and avoiding unnecessary optimizations. To sustain our momentum, we are focusing on performance as a key priority and are continuously evolving the architecture of our core features to accommodate future demands. We are currently re-engineering our Appointments Management Service from the ground up, utilizing modern event-driven, distributed technologies in line with our updated technology strategy. This pivotal service will revolutionize the way Care Teams manage appointments, ensuring patients receive quicker access to care.

Join Doctolib as a Senior Software Engineer specializing in JVM, Ruby, and React. In this pivotal role, you will design, develop, and optimize our software solutions to enhance healthcare accessibility across Europe. Collaborate with a talented team of engineers and play a key role in driving innovation in our technology stack.

Doctolib is hiring a Software Engineer with solid experience in Java and Kotlin. This position is based in Berlin and centers on building digital products that support both patients and healthcare professionals across Europe. Role overview This role involves working on software that aims to improve healthcare access and efficiency. The team values collaboration and a shared commitment to making a difference in the medical field. What you will do Collaborate with team members to design and implement new product features Develop and maintain applications using Java and Kotlin Help create solutions that make healthcare services easier to access and manage Location This role is based in Berlin, Germany.

Join our dynamic team to develop an innovative banking platform leveraging cutting-edge technologies and modern software development methodologies.Collaborate with a passionate group of software engineers and academics dedicated to revolutionizing the financial sector.Transform complex business challenges into effective technical solutions.Design and establish connections with major financial industry players to integrate Scalable Capital with the broader financial ecosystem.

Join our innovative team at redcare-pharmacy as a Senior Java Engineer. In this pivotal role, you will leverage your expertise in Java programming to develop robust, scalable applications that enhance our digital pharmacy solutions. Collaborate with cross-functional teams to drive the design and implementation of high-quality software solutions.We are looking for a proactive and detail-oriented engineer who thrives in a dynamic environment and is passionate about problem-solving. If you are ready to make a significant impact in the healthcare technology space, we want to hear from you!

Atolls is the world’s largest community-driven shopping platform, active in over 20 markets.We empower millions to make informed spending choices across discovery, evaluation, and (re-)purchase by connecting individuals with the ideal brands and retailers.Our team of 1,000+ members across 10 countries develops products utilized daily on a global scale, providing you with genuine ownership and the chance to witness your impact. Are you ready to help shape the destinations people trust for confident shopping? We invite you to learn more.About This Role:We are on the lookout for a Senior Java Backend Engineer to become an integral part of our expanding engineering team in Berlin. In this pivotal role, you will be responsible for designing, developing, and scaling high-performance backend systems utilizing contemporary Java technologies and cloud-native architectures. This position is perfect for individuals who thrive on tackling complex systems, prioritize code quality, and possess a robust architectural mindset.Our Benefits:At Atolls, we are committed to fostering both your professional and personal development. Here’s what you can look forward to:A culture that champions personal and professional growth, alongside opportunities for internal mobility.A supportive and open-minded team that welcomes diverse perspectives and innovative concepts.32 days of paid vacation plus an additional day off for your birthday, ensuring you have ample time to recharge.A flexible hybrid working model to help you find the right balance between work and life.Access to a learning budget and internal training to enhance your skills in your role.Mental health coaching to promote your well-being.Regular global and local gatherings to celebrate achievements and strengthen connections.The chance to take a sabbatical after three years with the company.A cloud-based company setup, allowing flexibility and collaboration regardless of your location.*These are global benefits applicable to all employees, with additional local perks based on your location.Responsibilities:As a Senior Java Backend Engineer, you will...

At Enpal, our vision is to empower every household with sustainable energy solutions. We strive to have a solar system on every roof, a storage unit in every home, and an electric vehicle in every garage. Our comprehensive approach to decentralized energy encompasses solar systems, battery storage, wall boxes, smart meters, and heat pumps. Central to this mission is our innovative AI-powered platform, Enpal.One+, which seamlessly connects thousands of systems while optimizing electricity procurement and feed-in on the energy market.Are you ready to create solutions that do more than just promise change? Join us at Enpal, where your contributions will deliver clean, renewable electricity and significantly enhance the quality of life for countless households.Your RoleAs a Senior Software Engineer - C# (f/m/x), you will tackle intricate challenges in delivering effective renewable energy solutions. Your responsibilities will range from digitalizing the planning processes for solar panel installations through engaging frontend applications to developing APIs that support real-time energy data management and scaling cloud infrastructure in Azure.We promote an agile environment that fosters rapid personal and professional growth. Our commitment to making sustainable solar energy accessible to all can only be achieved by uniting our customer-centric approach with collaborative efforts between software development, product management, and innovative, experiment-driven business development.Join us to enhance your skills, participate in the energy revolution, and work together towards the sustainable change we aspire to see in the world!Software Development: We prioritize delivering incremental value with each iteration and celebrate improvements that enhance user experiences and contribute to our climate goals.Developer Satisfaction: We aim to enhance stability and automate processes, minimizing the need for late-night deployments and repetitive manual regression tests.Continuous Learning: Whether you're an expert in Kafka or just starting with Azure Bicep, we welcome your knowledge and are committed to supporting your growth through continuous learning opportunities.Architectural Design: You will have the opportunity to work on architecture and technical design, ensuring our solutions are robust and scalable.

At Enpal, we're on a mission to revolutionize how energy is consumed. Our vision is to provide solar systems on every rooftop, battery storage in every home, and electric vehicles in every garage. Our comprehensive solutions encompass everything from solar installations to smart meters and heat pumps, all powered by our advanced AI platform, Enpal.One+. This innovative platform seamlessly connects a multitude of systems, optimizing energy procurement and feed-in across the market.Are you passionate about creating impactful solutions that enhance the quality of life for thousands of households? Your contributions at Enpal will not only help deliver clean energy but also foster a significant shift in energy usage for the future.Your RoleAs a Senior Software Engineer - Node.js (f/m/x), you will tackle intricate challenges in the realm of renewable energy solutions. Your responsibilities will range from digitizing solar panel installation planning with engaging frontend applications to developing APIs that provide real-time energy data. Additionally, you will be instrumental in scaling and managing our cloud infrastructure on Azure.We pride ourselves on our agility and commitment to professional development. Our vision of making sustainable solar energy accessible to everyone thrives on a customer-centric approach, fostering collaboration between software development, product management, and innovative business strategies.Join us in enhancing your professional journey, participating in the energy transformation, and taking shared responsibility for the sustainable future we aspire to create! We eagerly await your application.At Enpal, you will:Build Software: We prioritize delivering incremental value in every iteration, celebrating improvements that enhance user experience and help achieve our climate objectives.Enhance Developer Happiness: We aim to automate processes, reducing manual testing and deployment times, thereby improving the overall stability of our solutions.Grow & Learn: Whether you're an expert in Kafka or new to Azure Bicep, we are committed to facilitating your growth through shared knowledge and resources.Engage in Architecture & Design: Collaborate with cross-functional teams to design scalable and robust software architectures.

Join our Clickout-to-Revenue Team, where you'll be integral to our core business model: merchants pay for qualified redirects ("Clickouts") to their shops. Your role will ensure that this monetization operates smoothly, efficiently, and transparently, significantly contributing to idealos' growth.Your ResponsibilitiesEnd-to-End Responsibility You will develop and manage business and web applications in the AWS Cloud. Together with your team, you will oversee the entire value chain (YBYO): architecture, infrastructure, development, testing, security, deployment, monitoring, on-call duties, and maintenance. Product Focus: Monetization Processes and Services You will develop services for the representation and billing of our business models. Key components include the ERP system Odoo, internal data management tools, and interfaces to Salesforce and SAP. Innovative business models require innovative solutions; hence, you will closely collaborate with stakeholders such as our accounting, sales teams, account management, and other cross-functional engineering teams. Technical Excellence You will actively contribute ideas for process improvements, emphasize high code quality, and engage in continuous personal development – we support you with various training opportunities.

KAYAK, part of Booking Holdings (NASDAQ: BKNG), runs a large-scale travel search platform used by travelers worldwide to find flights, hotels, rental cars, and vacation packages. The company also offers KAYAK for Business, which provides travel management solutions to organizations. Its network includes well-known brands like momondo, Cheapflights, and HotelsCombined. KAYAK aims to make exploring the world easier by building the best travel search engine and values innovation and real impact from its employees. Role overview As a Senior Java Software Engineer based in the Berlin office, you will play a key role in developing and refining the features behind KAYAK’s search and booking systems. The team collaborates with over 200 travel partners, giving users access to more than 500,000 hotels and 550 airlines. Your work will help ensure smooth, reliable experiences for millions of users each day. This position requires onsite presence in Berlin at least three days per week. What you will do Enhance search and booking algorithms to meet the needs of major corporate clients worldwide. Develop and maintain high-performance integrations with third-party APIs, including those for airlines, hotels, and rental car providers. Take ownership of your designs from concept through deployment, with a focus on code quality and system performance. Join code reviews and architectural discussions to keep the K4B project modular and reusable as KAYAK continues to grow. Requirements Bachelor’s degree in Computer Science or a related field. At least 4 years of professional experience working with Java. Strong knowledge of the Spring ecosystem (Spring/Spring Boot) and hands-on experience with both relational (SQL) and NoSQL databases such as PostgreSQL, MySQL, or Redis. Clear and effective communication skills in English. Ability to independently design and deliver engineering projects.

Join idealo’s Clickout-to-Revenue team in Berlin, where the focus is on building and maintaining systems that help retailers monetize qualified referrals. The team’s work has a direct impact on idealo’s growth by ensuring monetization processes remain reliable and efficient. Both full-time and part-time arrangements are possible for this Senior Software Engineer position. What you will do Design, develop, and operate business and web applications on AWS Cloud. Take responsibility for the full lifecycle: architecture, infrastructure, development, testing, security, deployment, monitoring, and maintenance. Build and maintain services that handle processing and billing, integrating with key systems such as Odoo ERP and connecting to Salesforce and SAP. Work closely with colleagues from accounting, sales, account management, and other engineering teams to deliver solutions that meet changing business needs. Identify and implement process improvements, maintain high code quality, and pursue ongoing professional growth with support from idealo. Tech stack Kotlin Java AWS Odoo ERP Salesforce and SAP interfaces Location This role is based in Berlin, Germany.

At Enpal, we envision a world where every roof hosts a solar system, every home is equipped with a storage unit, and every garage houses an electric vehicle. Our innovative approach provides a comprehensive solution for decentralized energy, integrating solar systems, battery storage, wall boxes, smart meters, and heat pumps. Central to our mission is our advanced AI-driven platform, Enpal.One+, which seamlessly connects thousands of systems while optimizing electricity procurement and feed-in on the energy market.Are you prepared to contribute to real solutions that enhance the quality of life for countless households? The work you do at Enpal will not only provide clean energy for the future but also drive meaningful change in our energy consumption habits.In the Customer Domain, we take charge of the digital customer experience through our mobile app and web portal, empowering users to manage and monitor their energy systems effectively. Our teams focus on developing customer-centric features that genuinely address user needs while adhering to our high-quality standards. Customer feedback is the cornerstone of our development process.As a Senior Software Engineer (f/m/d), you will tackle intricate backend and platform challenges that underpin our customer-facing products.We pride ourselves on our rapid pace, agility, and the potential for significant career advancement. Our ambition to make sustainable solar energy accessible to everyone thrives on our focus on customer experience, collaboration between software development, product management, and our agile, experiment-driven business model.Join us in honing your skills and participating in the energy revolution as we collectively strive for sustainable change in the world!

About Enpal Enpal aims to build Europe’s largest renewable energy community by making solar energy accessible. Through a rental model for solar systems, electricity storage, and wall boxes, Enpal offers a bundled, all-inclusive solution. The company’s approach is digital, decentralized, and fully renewable, supporting rapid growth and direct action against climate change. Role Overview: Senior/Staff Software Security Engineer (F/M/X) This position is based in Berlin. The Senior/Staff Software Security Engineer will help protect Enpal’s applications throughout the Software Development Lifecycle (SDLC). Working closely with development, product, and DevOps teams, this role embeds security into every stage of software creation. Responsibilities include leading secure code reviews, running threat modeling sessions, and ensuring best security practices are followed. What You Will Do Build Secure Solutions: Deliver value in each development cycle, improving both customer experience and climate impact. Implement Shift-Left and Zero-Trust: Apply proactive security measures early and often, protecting applications, assets, and services from emerging threats. Develop Application Security Program: Collaborate with engineering and product teams to weave security into every phase of the SDLC, including design, development, testing, and deployment. Lead Threat Modeling and Risk Assessments: Organize threat modeling sessions, promote secure design, and carry out application-level risk assessments. Provide Security Training and Mentorship: Guide and train developers on secure coding practices, serving as a hands-on advisor. Why Join Enpal? Enpal offers a collaborative workplace focused on speed, agility, and growth. The company’s mission to make sustainable solar energy widely available depends on strong teamwork across software, product, and agile business units. This is a chance to advance your career while contributing to a sustainable future.

Your ImpactJoin our dynamic DIAL team within the Phone Assistant domain as a Senior Software Engineer. Your mission is to transform patient access to care and optimize daily practice management for healthcare providers through our innovative Phone Assistant solution.You'll collaborate within a feature team to develop cutting-edge AI-driven voice services that enhance phone interactions for millions of users in Germany, France, and Italy.At Doctolib, being part of our tech team means you are building impactful products and features aimed at improving the everyday experiences of care teams and patients alike.

At Enpal, we are more than just a company; we are a movement committed to transforming the energy landscape. As a prominent greentech unicorn and one of Europe’s fastest-growing energy companies, we strive to make solar energy accessible and hassle-free for homeowners across the continent. Our revolutionary business model, encompassing solar panels, heat pumps, home energy storage systems, and EV charging stations, is reshaping the residential energy market. Our mission is to empower homeowners to adopt clean energy solutions, paving the way for a sustainable, decentralized energy future.As a frontrunner in the residential solar energy sector, Enpal is on a growth trajectory with a clear vision: to spearhead Europe’s transition to sustainable and decentralized energy generation.Job OverviewWithin our Energy Platform, we oversee the integration and digital operation of Enpal’s products installed in customer homes. From optimizing heat pumps and enhancing the functionality of wallboxes to facilitating energy trading on the market, our platform supports all Enpal energy products. Our work spans embedded engineering for our proprietary IoT hardware, managing cloud infrastructure for fleet operations, and crafting user experiences.As a Senior Software Engineer (f/m/x) on our team, you will delve into and directly engage with intelligent and renewable energy systems. Your responsibilities will encompass everything from hardware collaboration to data ingestion and control of IoT devices via the cloud, as well as designing user-friendly experiences.We pride ourselves on speed, agility, and significant career advancement opportunities. Our vision of making sustainable energy accessible to all is realized through a customer-centric approach and collaboration between software development, product management, and lean, experiment-driven business development.Join us in honing your professional skills, participating in the energy revolution, and collaboratively driving the sustainable change we wish to see in the world! We eagerly await your application.Your Role at EnpalSoftware Development. We are committed to delivering incremental value with each iteration and celebrate improvements in user experience that positively impact our climate goals.Enhancing Developer Satisfaction. We strive to eliminate late-night deployments and tedious manual regression tests by focusing on improving stability and automating processes, including load testing and vulnerability scanning.

At Enpal, we are more than just a company; we are a movement aiming to transform the energy landscape. As a distinguished greentech unicorn and one of the fastest-growing energy firms in Europe, we are committed to making solar energy accessible and effortless for homeowners across the continent. Our innovative approach to solar panels, heat pumps, home energy storage systems, and EV charging stations is revolutionizing the residential energy market. With our mission to empower homeowners to adopt clean energy, we are paving the way for a sustainable and decentralized energy future.As a frontrunner in the residential solar energy sector, Enpal is expanding rapidly with a clear vision: to lead Europe’s transition towards sustainable and decentralized energy generation.Job OverviewIn the Energy Platform, we manage the integration and digital operation of Enpal’s products installed in customer homes. Whether it’s controlling heat pumps, enhancing the functionality of wallboxes, or trading energy on your behalf, we provide the platform for all Enpal’s energy solutions. Our responsibilities span from the embedded engineering of our own IoT hardware to managing cloud infrastructure that processes and optimizes our fleet and crafting exceptional user experiences.As a Senior Software Engineer (f/m/x) on our team, you will play a crucial role in building and shaping a cutting-edge Data Platform at the heart of our entire solar system fleet, empowering our other teams to deliver exceptional customer experiences.We offer a dynamic work environment with speed, agility, and significant career growth potential. Our vision to make sustainable energy accessible to all can only be realized through a customer and product-centered approach, and close collaboration among software development, product management, and lean, experiment-driven business development.Join us in developing your professional skills, participating in the energy revolution, and taking ownership of the sustainable changes we wish to see in the world together! We eagerly await your application.Your Role at Enpal:Software Development. We are focused on delivering incremental value with each iteration, celebrating improvements that enhance user experiences while contributing to our climate goals.Enhancing Developer Experience. We strive to minimize late-night deployments and repetitive manual testing. Our goal is to improve stability and automate as much as possible, including load tests and vulnerability assessments.Professional Growth. We foster an environment that encourages continuous learning and development.

Join Atolls, the world's largest community-driven shopping platform, active in over 20 markets.We empower millions to make informed spending choices across the discovery, evaluation, and (re-)purchase phases by connecting consumers with the right brands and retailers.Our diverse team of over 1,000 individuals across 10 countries develops products that millions use daily at a global scale. Here, you'll have true ownership of your work and witness its direct impact. Are you ready to help shape the shopping experiences that people trust? Keep reading.About This Opportunity:We are on the lookout for a Senior Software Engineer (Java/SpringBoot) to enhance our Shopping team based in Berlin. In this pivotal role at Atolls, you will play a critical part in enabling our consumers to maximize their value for money by delivering an outstanding shopping rewards experience online and in-store. You'll be instrumental in crafting exceptional user experiences, empowering consumers to make informed and confident shopping decisions. Your contributions will directly influence how millions of users engage with our platforms, guiding them towards making smart, fair, and rewarding choices.Our Perks:At Atolls, we are committed to fostering your professional and personal development. Here’s what we offer:A culture that champions personal and professional growth, coupled with internal mobility opportunities.A supportive and inclusive team that values diverse perspectives and innovative ideas.32 days of paid vacation plus your birthday off for optimal work-life balance.A flexible hybrid working model to accommodate your lifestyle.Access to a dedicated learning budget and internal training.Mental health coaching to support your well-being.Regular global and local events to celebrate achievements and foster connections.Opportunity for a sabbatical after three years with the company.

About KAYAKKAYAK, a member of Booking Holdings (NASDAQ: BKNG), stands as a premier travel search engine. With billions of queries on our platforms, we assist travelers in discovering their ideal flights, accommodations, rental cars, and vacation packages. We are also revolutionizing business travel with our innovative corporate travel solution, KAYAK for Business.As part of KAYAK, you will join a travel company that oversees a diverse array of global metasearch brands, including momondo, Cheapflights, and HotelsCombined. From our startup journey to becoming an industry trailblazer, innovation drives us, and every team member has the chance to leave a lasting impact. Our commitment is to develop the most efficient travel search engine, simplifying the process for everyone to explore the world.Position OverviewWe are in search of a proficient mid-level Java backend developer dedicated to implementing new features and maintaining KAYAK’s cutting-edge search and booking technology. Collaborating with over 200 travel partners and connecting to more than 500,000 hotels and 550 airlines, you will play a pivotal role in a dynamic team that ensures seamless operations, aiding millions in finding optimal accommodations and travel routes every day!This is a Fixed Term contract until September 30, 2027.This role requires working from our Berlin office a minimum of three days per week.Key ResponsibilitiesEnhance search and booking algorithms to meet the needs of our largest global corporate clients.Develop and sustain high-performance integrations with third-party APIs (airlines, hotels, and rental car providers).Take full ownership of your designs, from concept to deployment, while upholding exceptional standards for code quality and performance.Engage in code reviews and architectural direction to ensure the K4B project remains modular and reusable as KAYAK expands its enterprise reach.QualificationsBachelor’s degree or higher in Computer Science or a related field.5+ years of experience in Java programming.Hands-on experience with the Spring ecosystem (Spring/Spring Boot) and familiarity with relational (SQL) and NoSQL databases (e.g., PostgreSQL, MySQL, Redis).Excellent English communication skills.Ability to design and implement engineering initiatives with a focus on performance and usability.

idealo is looking for a Senior Backend Software Engineer (m|w|d) to join the team in Berlin. This role focuses on building and operating the backend for our mobile app, which helps millions of users compare prices and shop smarter. The team takes full ownership of technical implementation, operations, and strategic direction for our services, with a strong commitment to delivering a seamless experience for mobile shoppers. Role overview This position centers on end-to-end responsibility for business and web services in the AWS Cloud. The team manages the full lifecycle of these services, from architecture and infrastructure to development, testing, deployment, monitoring, and on-call support. The goal is to ensure stability, scalability, and high performance, especially during periods of heavy traffic. What you will do Develop and operate backend services in AWS Cloud for the mobile app Design and implement APIs (REST/GraphQL) for Android and iOS applications Make architectural decisions for backend systems, including microservices Enhance cloud infrastructure using tools such as Terraform and Kubernetes Maintain high code quality through testing, code reviews, and monitoring Identify and address technical debt Introduce new technologies and improve development workflows (CI/CD, automation, AI tools) Collaboration and impact Work closely with mobile engineers and backend colleagues Contribute to technical discussions and challenge existing solutions Share knowledge through pair programming, code reviews, and tech talks Communicate complex technical topics to non-technical stakeholders Participate in on-call rotations and take responsibility during critical incidents