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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Back End Engineer - **Company:** Número De - **Location:** Madrid, Spain - **Contract:** Permanent contract - **Skills:** Java (Programming Language), Amazon Web Services, Cloud Computing, Continuous Integration, Software Debugging, Distributed Systems, Software Architecture, Software Construction, Software Engineering, Software Systems, Backend, Kotlin, Deployment Automation, Software Coding - **Published:** August 28, 2026 - **Apply:** https://www.adzuna.es/contact-us.html ## About the Role + Proven experience building and launching a Sports betting application from scratch, with strong understanding of the technical requirements of Sportsbook platforms. + 7+ years of professional software development experience, with strong expertise in Java and/or Kotlin and Spring. + Demonstrated experience designing and implementing large-scale software systems, particularly distributed and highly scalable backend systems. + Strong understanding of backend architecture, system design, scalability, performance, and reliability. + Hands-on experience with AWS and cloud-based application environments. + Experience designing and maintaining CI/CD pipelines and modern software delivery practices. + Strong problem-solving and debugging skills, with the ability to investigate complex technical issues independently. + Ability to lead technical discussions, influence architectural decisions, and communicate clearly with both technical and non-technical stakeholders. + Strong collaboration skills and the ability to work effectively in an agile, cross-functional environment. + Good command of English, equivalent to at least B2 level. ## Description This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Back End Engineer - Sportsbook based in Spain. This is a senior engineering opportunity to help build a brand-new Sportsbook platform from the ground up. You will play a key role in shaping the backend architecture, technical foundations, and engineering practices behind a global gaming product. The position covers the full software development lifecycle, from understanding product requirements and system design through deployment, testing, and maintenance. You will work closely with cross-functional teams to turn ambitious product ideas into scalable and reliable technical solutions. As a senior technical contributor, you will influence architectural decisions, improve system performance, and establish strong engineering standards. The environment is agile, fast-moving, and highly collaborative, offering substantial ownership over the technology being built. It is an opportunity to make a direct impact on a new Sportsbook product and help define its technical direction from day one. Accountabilities + Design, develop, and maintain scalable, reliable, and efficient backend services for a new Sportsbook platform. + Contribute to the end-to-end development lifecycle, from framing product requirements and technical design through implementation, testing, deployment, and ongoing maintenance. + Collaborate with product, engineering, and other cross-functional stakeholders to understand business needs and translate them into clear technical specifications. + Lead architectural discussions and make informed technology decisions that improve scalability, performance, reliability, and maintainability. + Design and implement large-scale distributed systems capable of supporting a growing gaming platform. + Troubleshoot, debug, and resolve complex technical issues across backend services and production environments. + Establish and promote software engineering best practices, coding standards, testing approaches, and code-review processes. + Contribute to CI/CD practices and deployment automation to support reliable and efficient software delivery. + Help shape the technical roadmap and architecture of the Sportsbook as the product evolves. ## Related Videos - [Kotlin Multiplatform - True power of native code reuse](https://www.wearedevelopers.com/videos/4-kotlin-multiplatform-true-power-of-native-code-reuse) - [Developing the Backend with Stefan Lingler, CTO at Shpock](https://www.wearedevelopers.com/videos/100360-developing-the-backend-with-stefan-lingler-cto-at-shpock) - [Green Cloud Computing](https://www.wearedevelopers.com/videos/592-green-cloud-computing) - [Inside Bitpanda's Tech Stack: Scaling a European Fintech Leader - Markus Dorner](https://www.wearedevelopers.com/videos/1979-inside-bitpanda-s-tech-stack-scaling-a-european-fintech-leader-markus-dorner) - [Back(end) to the Future: Embracing the continuous Evolution of Infrastructure and Code](https://www.wearedevelopers.com/videos/440-back-end-to-the-future-embracing-the-continuous-evolution-of-infrastructure-and-code) - [Why Kotlin is the better Java and how you can start using it](https://www.wearedevelopers.com/videos/661-why-kotlin-is-the-better-java-and-how-you-can-start-using-it) ## Related Articles - [Top-Paying Tech Jobs (with Salaries)](https://www.wearedevelopers.com/magazine/372-top-paying-tech-jobs-with-salaries) - [What’s the Difference Between Frontend and Backend Development?](https://www.wearedevelopers.com/magazine/240-what-s-the-difference-between-frontend-and-backend-development) - [The Most Popular IT Jobs on the Market](https://www.wearedevelopers.com/magazine/376-the-most-popular-it-jobs-on-the-market) - [20 Essential Tools For Backend Development](https://www.wearedevelopers.com/magazine/218-20-essential-tools-for-backend-development) - [7 Most Popular Web Developer Jobs in Europe](https://www.wearedevelopers.com/magazine/163-7-most-popular-web-developer-jobs-in-europe) - [Fully Remote Software Engineer Jobs](https://www.wearedevelopers.com/magazine/447-fully-remote-software-engineer-jobs)