Senior Software Engineer – Java

TENIOS GmbH

Senior Java Engineer building and operating cloud-native communications services for TENIOS. Developing Java microservices, telecom integrations, AI voicebots, and resilient Kubernetes deployments.

Posted 8/23/2026full-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 21+/Spring-based backend systems and microservices architecture. Proficient in implementing secure coding practices and managing CI/CD pipelines to ensure high availability and compliance.

Highest-signal resume keywords

Java 21+/Spring DevelopmentMicroservices ArchitectureCI/CD ManagementCloud Platform Experience (AWS, Azure, GCP)Observability Tools

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills

JavaSpring BootMicroservicesDockerKubernetesRabbitMQSIPRTPWebSocketsAutomated Testing

Soft Skills

Analytical ThinkingTechnical Decision-MakingCollaboration

Tools & Technologies

FreeSWITCHKamailioGitHub ActionsGitLab CIJenkinsArgo CD

Certifications & Qualifications

ISO 27001 Compliance

Industry Keywords

Cloud CommunicationsTelecommunications ProtocolsCPaaSLow-Latency SystemsAsynchronous Messaging

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 using open-source softswitches and SIP proxies such as FreeSWITCH and Kamailio
Implement advanced ACD engines and AI-powered IVR workflows
Integrate real-time AI voicebot platforms via WebSockets/RTP
Further develop and scale the Java 21+/Spring-based backend platform using microservices and RabbitMQ
Expand multi-tenant capabilities, including isolation, metering, and resource partitioning
Maintain and further develop automated usage-rating, billing, and invoicing engines
Apply secure coding practices to support ISO 27001 and NIS 2 compliance
Manage CI/CD pipelines, Kubernetes deployments, and observability to ensure 99.99%+ availability
Maintain and further develop existing Backbone.js and Marionette.js management interfaces, while leading the migration to modern frontend frameworks
Use and promote AI-assisted development tools and agent-based CLI workflows
Collaborate with Platform Engineering, Security, and Product teams

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, Spring Framework, JPA/Hibernate, and RESTful API design
Experience designing and implementing distributed, cloud-native applications using microservices
Practical 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
Good understanding of secure development practices (OWASP Top 10, dependency and secrets management)
Experience with observability tools covering metrics, centralized logging, distributed tracing, and APM
Proficiency in 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 is a plus
Practical experience with AI-assisted development tools or a genuine openness to using them
Experience with CPaaS or cloud communications platforms, telecommunications protocols (SIP, RTP, WebRTC), or related open-source frameworks is a plus
Knowledge of carrier-grade, highly available, low-latency distributed systems is a plus
Experience with asynchronous messaging/event-driven architectures (Kafka, RabbitMQ) is a plus

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
A strong focus on artificial intelligence and technology: work daily with cutting-edge AI solutions and digital tools
An international, highly productive team with fast decision-making processes and a tangible impact on the company’s growth