(Senior) Backend Engineer – Golang

7nxt-Gmbh; Berlin; Hybrid; EUR 90,000 - 130,000; Full time

Benefits offered by this job

Hybrid working model

Mobility budget

Training budget

Pet‑friendly office

Wellbeing & health perks

Job summary

Gymondo is seeking a (Senior) Backend Engineer to build and evolve our scalable backend systems powering hundreds of thousands of users. You will create services with clean architecture, modern tech stack, and translate legacy concepts into maintainable code.

You’ll drive REST APIs, microservice reliability and data‑driven features, while working in a hybrid Berlin setup with English as the working language.

Qualifications

• 4+ years of backend‑focused development, including infrastructure.
• 3+ years contributing to microservice architectures with reliability, scaling and clean architecture.
• 3+ years designing REST APIs following OpenAPI standards.
• Proven hands‑on experience with Golang and Gin‑Gonic.
• Ability to design proofs of concept and prototypes.
• Standardised coding practices: peer code reviews and unit testing.
• An open mindset and interest in state‑of‑the‑art technologies.
• Fluent English.

Responsibilities

• Build, improve and maintain scalable backend services using Golang and Gin‑Gonic.
• Design and implement REST APIs following OpenAPI standards.

Skills

Golang

Gin-Gonic

OpenAPI

Microservices

AWS

Kubernetes

Terraform

Unit testing

Tools

Docker

Kubernetes

Terraform

Job description

The essentials

Team: Product & Engineering

Start date: As soon as possible

Location: Berlin — hybrid, 3 days in the office

Working language: English (German: a plus)

Salary band: Shared before your first interview

Your impact

As (Senior) Backend Engineer 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.

What you’ll drive

• You build, improve and maintain scalable backend services using Golang and Gin-Gonic, following clean architecture and established design patterns




• You design and implement REST APIs following OpenAPI standards, with a focus on clarity, reliability and long‑term maintainability




• You contribute to our microservice architecture — working on reliability, scaling, stateless applications and event‑driven systems




• You rebuild legacy concepts and translate them into well‑known programming patterns with transparent and maintainable business logic




• You develop data-driven features and are involved in all stages of the development process — from design to deployment




• You work on our scalable, automated infrastructure using AWS, Kubernetes and Terraform




• You participate in peer code reviews, write unit tests and champion agile development practices




• You share knowledge, discuss better solutions openly and grow together with the team

Must-have

• 4+ years of professional experience in backend‑focused development, including infrastructure




• 3+ years contributing to microservice architectures with a focus on reliability, scaling, stateless applications, event‑driven systems and clean architecture




• 3+ years designing REST APIs following OpenAPI standards




• Proven hands‑on experience with Golang and Gin‑Gonic




• Ability to design proof of concepts and prototypes




• Standardised coding practices: peer code reviews, unit testing and a preference for agile development




• An open mindset and genuine interest in state‑of‑the‑art technologies and methodologies




• Fluent English

Nice-to-have

• Experience with JVM languages (Kotlin / Java) and frameworks such as Ktor, Spring or Node.js




• 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




• Strong communication skills across the Product & Engineering team and additional stakeholders




• A collaborative, humble approach — you promote good relationships in your guild and are always willing to learn from others

Our tech stack

Golang, Kotlin, Node.js, Java 17 · Gin‑Gonic, Ktor, NestJS, Spring Boot · Elasticsearch, MySQL, PostgreSQL, DynamoDB, MongoDB, Redis · Terraform, Docker, Kubernetes · Event‑Driven Architecture · AWS

Benefits

Success requires positive energy. That's why we ensure the right conditions are in place — physically, mentally, and within the team:

• 30 days of vacation per year + Christmas Eve & New Year's Eve as additional paid days off




• Hybrid working model — 60% in the office, 40% from home, applicable to all working hours




• Up to 4 weeks of work from abroad per year (Berlin‑based roles)




• Free Urban Sports Club M membership & access to Nilo Health for mental health and personal development




• Free access to 7Mind, Gymondo & Buddyfit — our own digital wellbeing products




• €30 monthly mobility budget via Navit




• €1,000 annual training budget + a wide range of opportunities for personal growth and development




• Family‑friendly benefits — childcare costs & paid sick days for children




• The office classics — fruit & vegetable basket, muesli & yogurt (also vegan), drinks & snacks




• Pet‑friendly office — four‑legged colleagues are very welcome!

These benefits apply to full‑time and part‑time permanent employees. Working students and interns receive a pro‑rated selection.

People who make things happen

Gymondo is one of the leading digital fitness and nutrition platforms in the DACH region — with over 2,000 workouts, holistic training programmes and smart nutrition plans. As part of 7NXT Health Group, we help millions of people make movement a lasting part of their everyday lives.

Our team pushes each other, thinks critically and grows together. We take responsibility — for our users, our products and our planet.

Everyone counts

We welcome what makes you unique.

At Gymondo we believe in diversity, openness and team spirit. No matter which gender you identify with, whether you have a disability, what your neurotype is, where you come from, what you believe in or how you love — you are welcome here.

Don’t meet all the criteria? No problem — if you’d like to help shape the future of fitness & wellbeing with us, we look forward to your application.

Need a more accessible process or have questions? Write to us — we’ll find a way.