Senior Software Engineer, Java

TENIOS GmbH

. Take end-to-end ownership (“you build it, you run it”) of the cloud-native communications platform .

Posted 9/19/2026full-timeCologne • GermanySenior💰 €67,000 - €72,000 per yearWebsite

Core Competencies

Role fit

Core Competencies

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Demonstrates expertise in developing and maintaining cloud-native communications platforms, with a strong focus on Java-based backend systems, microservices architecture, and secure coding practices. Proficient in managing CI/CD pipelines and ensuring high availability and compliance with cybersecurity standards.

Highest-signal resume keywords

Java 21+/Spring FrameworkMicroservices ArchitectureCI/CD Pipeline ManagementCloud Platform Experience (AWS/Azure/GCP)Secure Coding Practices (OWASP)

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Hard Skills

Java 21+Spring BootJPA/HibernateRESTful API DesignDockerKubernetesRabbitMQObservability ToolsAI-Assisted Development ToolsTelecommunications Protocols (SIP/RTP/WebRTC)

Soft Skills

Analytical ThinkingTechnical Decision-MakingCollaboration

Tools & Technologies

FreeSWITCHKamailioGitHub ActionsGitLab CIJenkinsArgo CD

Certifications & Qualifications

ISO 27001 Compliance

Industry Keywords

Cloud CommunicationsCPaaSDistributed SystemsLow-Latency SystemsEvent-Driven Architecture

Tech Stack

Tools & technologies

AWSAzureCloudDockerGoogle Cloud PlatformHibernateJavaJavaScriptJenkinsKafkaKubernetesMicroservicesRabbitMQSpringSpring BootSpringBoot

About the role

Key responsibilities & impact

Take end-to-end ownership (“you build it, you run it”) of the cloud-native communications platform
Develop and maintain low-latency call-control systems that integrate with FreeSWITCH and Kamailio
Build ACD engines and AI-powered IVR workflows
Integrate real-time AI voicebot platforms into telephony workflows via WebSockets/RTP
Further develop and scale the backend platform using Java 21+/Spring-based microservices and RabbitMQ
Expand multi-tenant capabilities, including isolation, metering, and resource partitioning
Maintain and enhance usage-rating, billing, and invoicing engines
Apply secure coding practices such as OWASP guidance, threat modeling, and dependency scanning
Support ISO 27001 compliance and European NIS2 cybersecurity requirements
Manage CI/CD pipelines, Kubernetes deployments, and observability
Ensure platform availability of 99.99%+
Maintain existing Backbone.js and Marionette.js management interfaces and lead the migration to modern frontend frameworks
Use and promote AI development tools and agent-based CLI workflows for coding, refactoring, and software delivery
Collaborate closely with Platform Engineering, Security, and Product

Requirements

What you’ll need

At least 5 years of professional software development experience, with a strong focus on Java-based backend systems
In-depth knowledge of modern Java (17/21+), Spring Boot, the Spring Framework, JPA/Hibernate, and RESTful API design
Experience designing and implementing distributed, cloud-native applications based on microservices
Hands-on experience with Docker, Kubernetes, and at least one modern CI/CD tool (e.g., GitHub Actions, GitLab CI, Jenkins, Argo CD)
Experience with at least one major cloud platform (AWS, Azure, or GCP)
Solid understanding of quality practices, including automated testing, code reviews, and CI/CD
Strong understanding of secure development practices (OWASP Top 10, dependency and secrets management)
Experience with observability tools, including metrics, centralized logging, distributed tracing, and APM
Confident operating production systems and responding to incidents
Strong analytical thinking and sound technical decision-making in complex distributed systems
Fluent English, both written and spoken
German language skills are a plus
Hands-on experience with AI-assisted development tools (e.g., Claude Code, GitHub Copilot), or genuine openness to using them
Experience with CPaaS or cloud communications platforms, telecommunications protocols (SIP, RTP, WebRTC), or related open-source frameworks (FreeSWITCH, Kamailio, Asterisk)
Knowledge of carrier-grade, highly available, low-latency distributed systems
Experience with asynchronous messaging and event-driven architectures (Kafka, RabbitMQ)

Benefits

Comp & perks

Gross annual salary of €67,000 to €72,000, depending on experience
Hybrid working model based in Cologne
An international B2B technology environment
Focus on AI and technology: daily work with cutting-edge AI solutions and digital tools
An international, highly productive team with fast decision-making and a meaningful impact on the company’s growth