(Senior) Software Security Engineer (f/m/d)

At IONOS, the leading European provider of cloud infrastructure, cloud services and hosting services, you will work together with a wide range of teams. We are characterized by open structures, a friendly working culture and flat hierarchies with a strong team spirit. We firmly believe that work and fun are compatible, and offer you the right environment for this. Our constant growth means that we are always looking for new colleagues. Become part of IONOS and grow with us.

IONOS Cloud Development is strengthening its security engineering capabilities. We are looking for a (Senior) Software Security Engineer who will work directly with our product engineering teams to scale secure software development across the organization.

This is a hands-on engineering role. You will design and build security automation, tooling, and reusable security patterns that make secure coding seamless for hundreds of developers building products for the IONOS Cloud platform.

If you are motivated by solving complex problems through code, improving developer experience, and integrating security deeply into cloud-native development workflows, we’d like to meet you.

Tasks

• Design and implement security automation and tooling that integrate into the software development and deployment lifecycle.
• Build and maintain internal developer tools such as libraries, SDKs, CI/CD plugins, and policies-as-code systems.
• Contribute code directly to platform and product services for vulnerability remediation, configuration hardening, and secure pattern adoption.
• Work with engineering teams to embed lightweight and actionable threat modeling early in the feature lifecycle.
• Develop and promote secure-by-default patterns and components (e.g. crypto usage, validation, secure configuration, error handling, logging).
• Collaborate with product teams, platform teams, DevOps, and compliance peers to translate security requirements into practical engineering solutions.
• Analyze recurring issues and drive systemic improvements into tooling, documentation, processes, and developer experience.

Qualifications

• Several years of experience in AI driven software engineering with proficiency in Go, Rust, Java or C.
• Strong communication and visualization skills for presentation.
• In-depth understanding of secure coding practices, common vulnerability classes, and cloud-native architectures (Kubernetes, microservices, CI/CD).
• Ability to design, implement, test, and maintain production-grade code.
• Hands-on experience building internal developer tooling, such as SDKs, libraries, CI/CD plugins, or policies-as-code systems.
• Experience with SAST/DAST integration, dependency scanning, fuzzing, or supply chain security.
• Experience in large-scale cloud or platform environments.

Language Requirements

• German and English fluently

Note: At the end of the application process, candidates must undergo a security check (SÜ2). Your consent will be requested in good time during the process. 

If you are passionate about raising engineering standards, enabling teams through knowledge, and contributing directly to modern Cloud-Native development practices, we invite you to apply.

Benefits

• Hybrid working model.
• Flexible working hours through trust-based working hours.
• At some locations a subsidized canteen and various free drinks.
• Modern office space with very good transport connections.
• Various employee discounts for activities and products.
• Employee events such as summer and winter parties, as well as workshops.
• Numerous training and development opportunities.
• Various health offers, such as sports and health courses.

 

About IONOS

IONOS is the leading European digitalization partner for small and medium-sized businesses (SMB). The company serves around six million customers and operates across 18 markets in Europe and North America, with its services being accessible worldwide. With its Web Presence & Productivity portfolio, IONOS acts as a 'one-stop shop' for all digitalization needs: from domains and web hosting to classic website builders and do-it-yourself solutions, from e-commerce to online marketing tools. In addition, the company offers Cloud Solutions to enterprises who are looking to move to the cloud as their businesses evolve. 

We value diversity and welcome all applications - regardless of, for example, gender, nationality, ethnic or social origin, religion, disability, age as well as sexual orientation and identity, physical characteristics, marital status or any other irrelevant factor subject to applicable law.