(Senior) Backend Engineer – Golang

<h2>The essentials</h2><p><strong>Team:</strong> Product & Engineering</p><p><strong>Start date:</strong> As soon as possible</p><p><strong>Location:</strong> Berlin — hybrid, 3 days in the office</p><p><strong>Working language:</strong> English (German: a plus)</p><p><strong>Salary band:</strong> Shared before your first interview</p><h2>Your impact</h2><p>As <strong>(Senior) Backend Engineer</strong> at Gymondo, you build and improve the scalable backend systems that power our platform for hundreds of thousands of active users. You work with a modern tech stack, establish new services using clean architecture principles, and help translate legacy concepts into maintainable, future-proof code. Your work directly shapes the technical foundation that enables Gymondo to grow — reliably, efficiently and at scale.</p><h2>What you’ll drive</h2><ul><li><p>You build, improve and maintain scalable backend services using Golang and Gin-Gonic, following clean architecture and established design patterns</p></li><li><p>You design and implement REST APIs following OpenAPI standards, with a focus on clarity, reliability and long-term maintainability</p></li><li><p>You contribute to our microservice architecture — working on reliability, scaling, stateless applications and event-driven systems</p></li><li><p>You rebuild legacy concepts and translate them into well-known programming patterns with transparent and maintainable business logic</p></li><li><p>You develop data-driven features and are involved in all stages of the development process — from design to deployment</p></li><li><p>You work on our scalable, automated infrastructure using AWS, Kubernetes and Terraform</p></li><li><p>You participate in peer code reviews, write unit tests and champion agile development practices</p></li><li><p>You share knowledge, discuss better solutions openly and grow together with the team</p></li></ul><h2>What defines you</h2><h3>Must-have</h3><ul><li><p>4+ years of professional experience in backend-focused development, including infrastructure</p></li><li><p>3+ years contributing to microservice architectures with a focus on reliability, scaling, stateless applications, event-driven systems and clean architecture</p></li><li><p>3+ years designing REST APIs following OpenAPI standards</p></li><li><p>Proven hands-on experience with Golang and Gin-Gonic</p></li><li><p>Ability to design proof of concepts and prototypes</p></li><li><p>Standardised coding practices: peer code reviews, unit testing and a preference for agile development</p></li><li><p>An open mindset and genuine interest in state-of-the-art technologies and methodologies</p></li><li><p>Fluent English</p></li></ul><h3>Nice-to-have</h3><ul><li><p>Experience with JVM languages (Kotlin / Java) and frameworks such as Ktor, Spring or Node.js</p></li><li><p>A Product Engineer mindset: balancing technical excellence with business impact, proactively identifying trade-offs that prioritise user value and speed-to-market without compromising long-term system health</p></li><li><p>Strong communication skills across the Product & Engineering team and additional stakeholders</p></li><li><p>A collaborative, humble approach — you promote good relationships in your guild and are always willing to le