Software Developer specializing in Ktor Framework

About the Role scalablegmbh is looking for a Senior Kotlin / Java Software Engineer focused on Application Framework development in Berlin. This position centers on designing and building scalable applications that support core business functions. The work directly influences our technology choices and strengthens the software we deliver.

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.

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 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.

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.

At Flix, we foster a technology-driven culture where creativity meets significant real-world applications. We offer competitive compensation, ample opportunities for professional advancement, and a collaborative environment that encourages ownership and innovation.We are on the lookout for a Software Engineer (Kotlin, Java) with robust Kotlin (or Java with a willingness to learn Kotlin) expertise to become a key member of our Capacity Management team in the Demand Division. The Capacity Management team is responsible for developing and maintaining systems that allocate, price, and manage seat availability across Flix. Our team handles high-throughput, real-time data pipelines and event-driven microservices to ensure smooth operations, even in unpredictable situations.As a Software Engineer at Flix, you will have the opportunity to influence systems that directly affect how millions of passengers book their seats and optimize Flix's capacity across our global network in real-time.Our tech stackLanguages & Frameworks: Kotlin, Spring Boot, Akka/PekkoData & Messaging: PostgreSQL, Kafka

About Our Team At SumUp, we provide a cutting-edge Point-of-Sale (POS) solution that empowers businesses such as cafes, shops, bars, and hair salons to operate seamlessly and grow. Our platform boasts a vast array of features, including product catalogs, inventory management, business analytics, compliance support, and loyalty tools. Our POS solution integrates flawlessly into the SumUp SuperApp, which is compatible with our proprietary register hardware as well as mobile devices like tablets and smartphones. As a Senior Android Developer, you will work alongside an innovative, cross-functional team consisting of Product Managers, Product Designers, Engineering Managers, and fellow developers. About the Role We are transitioning towards a Kotlin Multiplatform (KMP) strategy, facilitating shared development between Android and iOS. In this role, you will gain experience with this technology, helping to shape the future of our mobile applications. If you are a developer who prioritizes user-centric design, precision, and effective collaboration, you will thrive here. You bring structure to communication and flourish within a cross-functional environment. This position is based in Berlin, where face-to-face interactions fuel innovation and teamwork. Your Responsibilities Develop new features for the item catalog within the SumUp SuperApp Improve application architecture and actively contribute to our Kotlin Multiplatform strategy Enhance and maintain our unified Android app, utilized in over 60 countries, ensuring high-quality and scalable solutions Drive product evolution by identifying improvement opportunities and participating in daily decision-making Create comprehensive documentation and implement thorough testing for features prior to release Work closely with Designers, Product Managers, and Android engineers to ensure a cohesive UX experience across platforms Mentor and coach junior engineers You Will Excel in This Role If: You possess 8+ years of experience in mobile engineering, particularly with Android and Kotlin. You have 2+ years of experience with Jetpack Compose. You have a strong grasp of software design patterns (e.g., MVVM, MVI) and expertise in creating modular, scalable app architectures. You are knowledgeable about reactive programming (Flow, Coroutines, and Concurrency).

Join us at Delivery Hero as an Engineering Manager specializing in Java/Kotlin for our Logistics Workforce Tribe. We are dedicated to delivering exceptional experiences and are looking for a leader to help us achieve this goal.As part of our Logistics Team, you will address significant challenges to enhance last-mile delivery, making it more efficient, affordable, and sustainable. Your contributions will directly enhance the experiences of riders, end customers, and merchants worldwide. Each improvement you implement will assist Delivery Hero in optimizing our delivery operations, facilitating our expansion into new sectors such as grocery and retail.The Workforce Tribe Team:Riders serve as the backbone of our last-mile delivery, enabling the fulfillment of millions of orders daily.Our Workforce Tribe is responsible for managing gross and net earnings, a wallet for riders to withdraw their earnings, staffing and work scheduling, performance management, loyalty programs, personalized campaigns and goals, recruitment of new riders, and document management for our million-strong rider community.The rider experience with Delivery Hero is our core metric, and you will be at the helm of one of the squads that directly influences this metric.Your Role:Collaborate with your product counterpart to provide technical guidance to your team, facilitating the design of feasible and iterative solutions that align with our business needs.Take ownership of the technical metrics and KPIs for your team, ensuring complete visibility, monitoring, and alerting.Enhance and support the incident resolution process and the team's on-call practices.Mentor junior team members, providing both technical and non-technical guidance.Manage relationships with both technical and non-technical stakeholders, effectively navigating and resolving challenges.

At JetBrains, we are passionate about code. Since our inception in 2000, we have dedicated ourselves to creating the most powerful and effective developer tools available. By automating routine checks and corrections, our tools enhance productivity, enabling developers to innovate and create freely. Kotlin, a modern programming language developed by JetBrains, targets Java, Android, JavaScript, and native platforms. Since its introduction in 2016, Kotlin has rapidly gained traction, becoming the official language for Android development and receiving support from numerous frameworks, engines, and tools. With Kotlin Multiplatform and Compose Multiplatform, our mission is to empower Android developers to create exceptional multiplatform applications. The Kotlin Multiplatform Tooling team is at the forefront of this initiative, developing tools that simplify the process. We are actively working on Kotlin Multiplatform plugins for IntelliJ IDEA and Android Studio, alongside enhancing IntelliJ IDEA's Android support, KDoctor, and the Kotlin Multiplatform wizard. We are looking for a passionate Android developer who can share their insights and experience with our team while contributing to the development of tools that they have always envisioned. Our international and friendly team welcomes applicants who share our enthusiasm for coding.

flix is hiring a Full-stack Engineer to join the Payments Team in Berlin. This team develops and maintains the systems that process payments, focusing on both a smooth user experience and the company’s business needs. Java and Kotlin are key technologies in this role. What you will do Collaborate with colleagues across disciplines to design, build, and launch new payment features Support and enhance the systems that process payments for flix customers Share ideas and technical knowledge to help shape the direction of the payment platform Requirements Strong experience with Java and Kotlin Interest in building payment solutions Ability to work onsite in Berlin Location This role is based in Berlin.

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

JetBrains has developed tools for software teams since 2000. By automating routine checks and corrections, JetBrains products help developers focus on building and shipping software. The goal: make development more productive and creative. Role overview This Backend Customer Success Engineer role centers on supporting engineering teams as they adopt Kotlin for backend development. The position focuses on helping organizations successfully bring Kotlin into production environments. What you will do Guide organizations through the process of moving from Java to Kotlin, assisting with migration, integration, and scaling. Troubleshoot technical challenges that arise during the transition and support teams as they progress from initial experimentation to stable production use. Work with potential users to clarify how Kotlin adoption works and help design migration plans that fit their specific needs. Locations Amsterdam, Netherlands Berlin, Germany Munich, Germany Prague, Czech Republic Remote, Germany

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.

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.

JetBrains s.r.o. creates tools that help developers automate repetitive tasks so they can focus on writing quality code. Since 2000, the company has aimed to make software development more productive and enjoyable for engineers worldwide. Role overview The Customer Success Engineer - Kotlin Multiplatform (KMP) supports engineering teams as they adopt KMP in real-world projects. This role guides organizations from their first evaluation through to successful deployment. Along the way, it gathers feedback and collaborates closely with JetBrains product teams to help shape the future of KMP. What you will do Work directly with organizations at various stages of KMP adoption, from initial exploration to production rollout. Assist teams in migrating, integrating, and scaling shared codebases using Kotlin Multiplatform. Support teams moving from experimentation to production and help address technical challenges as they arise. Reach out to potential users who could benefit from adopting KMP. Identify each customer’s technical needs, use cases, and any barriers to adoption. Advise on architecture, feasibility, and strategies for implementing KMP. Collect structured feedback and insights from clients. Collaborate with JetBrains product and engineering teams to influence the KMP roadmap and improve available tooling. Common questions you'll help solve What is the safest way to migrate a large Android app to shared logic? How much code sharing is practical or advisable? How can teams address resistance from iOS developers working with Kotlin APIs? What’s the best way to organize a codebase for collaboration across teams? How can teams resolve slower build times after introducing KMP? How success is measured Organizations deliver Kotlin Multiplatform in production environments. Teams increase their use of shared code over time. KMP adoption continues beyond initial trials. User feedback results in tangible improvements to KMP and its tooling. Requirements Experience working with Kotlin, either for Android or backend development. Understanding of mobile architectures on both Android and iOS, especially with Kotlin. Strong communication skills and a knack for problem solving. Background with cloud technologies and CI/CD pipelines. Ability to collaborate effectively within a team-driven environment. Location This position is available in Amsterdam (Netherlands), Berlin or Munich (Germany), or remote within Germany.

Join Our Innovative TeamAt SumUp, we provide powerful Point-of-Sale (POS) solutions that empower diverse businesses such as cafes, shops, bars, and salons to thrive. Our platform features robust tools for product management, inventory oversight, business analytics, regulatory compliance, and customer loyalty programs.Our advanced POS solution is seamlessly integrated into the SumUp SuperApp, supporting both our proprietary hardware and a variety of mobile devices.As an Android Developer, you will work alongside a talented, cross-functional team comprising Product Managers, Designers, Engineering Managers, and fellow developers.Your RoleWe are transitioning to a Kotlin Multiplatform (KMP) strategy to facilitate shared development for both Android and iOS applications. In this dynamic role, you will gain expertise, refine your skills, and contribute to the evolution of our mobile applications.You are a developer who prioritizes user-centric design, values clear communication, and excels in collaborative environments.On-site Collaboration in BerlinWe believe that in-person interactions drive innovation and teamwork, making this role exclusively on-site in Berlin.Your ResponsibilitiesDevelop and enhance features for the item catalog within the SumUp SuperApp.Contribute to the architectural improvement of the application while supporting our Kotlin Multiplatform initiative.Maintain and enhance our unified Android application, serving over 60 countries and ensuring high-quality, scalable solutions.Identify areas for enhancement, influencing product evolution and participating in daily decision-making.Create comprehensive documentation and execute thorough testing for new features prior to deployment.Work closely with Designers, Product Managers, and Android engineers to provide a cohesive user experience across platforms.Mentor and coach junior engineers.Who You AreYou possess 3+ years of experience in mobile engineering, specifically with Android and Kotlin.You have 2+ years of experience utilizing Jetpack Compose.You have a strong understanding of software design patterns (e.g., MVVM, MVI) and are skilled in creating modular, scalable app architectures.You are passionate about user-centric design and thrive in a collaborative environment.

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.

About Speechify Speechify builds text-to-speech tools that help over 50 million people turn reading materials, PDFs, books, Google Docs, articles, and websites, into audio. Users read faster, retain more, and access content in ways that work for them. Our products span iOS, Android, Mac, Chrome Extension, and Web App. Google named us Chrome Extension of the Year, and Apple recognized us with the 2025 Design Award for Inclusivity. Nearly 200 colleagues work remotely from around the world, drawing on experience from Amazon, Microsoft, Google, Stanford, Stripe, Vercel, and more. Role Overview: Senior Software Engineer, Windows/Desktop Applications This role is based in Berlin, Germany. The focus: building and evolving Speechify’s native Windows desktop applications. What You Will Do Design, architect, and develop native Windows desktop apps using Windows App SDK, WinUI (or similar), C#, XAML, and sometimes C++. Define and promote best practices for Windows development, covering code structure, performance, memory management, responsive UI, and compatibility across Windows 10 and 11. Lead accessibility improvements, ensuring apps work well with accessibility APIs like Microsoft UI Automation and that UI controls are usable for people with disabilities. Collaborate with product designers, UX researchers, QA, and other teams to plan features, shape UI/UX, and set the Windows platform roadmap. Own features from concept through design, implementation, testing, release, and ongoing maintenance, aiming for high quality and consistency. Troubleshoot and resolve complex issues, bugs, performance bottlenecks, memory leaks, and compatibility problems, while recommending sound architectural solutions.