Senior Backend developer (C# )

Arηs is a fully independent group of companies specialized in managing complex IT projects and systems for large organisations, focusing on state-of-the-art software development, business intelligence and infrastructure services.

We are composed of 16 entities across 8 countries worldwide that are unified by the Arηs Group, with more than 2500 consultants. This corporate structure enables us to respond quickly to market changes and customer requests, and to communicate and make decisions without layers of bureaucracy.

Established in 2016, the Greek entity Arηs Developments Hellas aims to extend Arηs Group activities dedicated to the European market providing high-quality services in Software Development, covering the entire application development lifecycle.

We are seeking a Senior Backend Engineer to design, develop, and optimize backend microservices in a large-scale, cloud-based environment. Leveraging Domain-Driven Design (DDD), you will define bounded contexts aligned with business domains, ensuring scalable, resilient, and maintainable architectures. You'll work closely with cross-functional teams, including architects, project managers, analysts, frontend developers, and ICT support teams to deliver high-quality solutions aligned with both business and technical goals.

Key Responsibilities:

• Architecture & Development:

  • Lead the design and implementation of scalable, high-performance microservices using DDD.

  • Decompose monolith applications into modular, independently deployable services.

  • Design and document secure REST and WebSocket-based APIs.

  • Implement token-based authentication (e.g., JWT, OAuth2) to secure backend systems.

  • Optimize applications for performance, scalability, and cost-effective deployment in cloud platforms (Azure, AWS).

• Collaboration & Leadership:

  • Collaborate with the Architecture Team, Business Capability Sector, and Application Support to align solutions with enterprise standards.

  • Work closely with frontend engineers to ensure seamless API integration and aligned response structures.

  • Mentor junior developers and lead Agile ceremonies, promoting DevOps best practices and continuous improvement.

• Analysis & Documentation:

  • Translate business requirements into technical designs in collaboration with architects and analysts.

  • Prepare and maintain HLA, HLD, and LLD documentation or equivalent Agile artifacts (e.g., user stories).

  • Document microservice designs, including functionality, dependencies, API specs, and deployment guides.

• Quality Assurance & Performance:

  • Conduct code reviews to enforce standards, improve quality, and provide feedback.

  • Analyze backend services to identify and eliminate bottlenecks through refactoring and optimization.

  • Implement performance testing, load balancing, and caching strategies to ensure robust performance.

• Strategic Contributions:

  • Define microservice boundaries using DDD.

  • Contribute to backend architecture evolution and continuous documentation practices.

  • Identify and mitigate risks related to integration, scalability, performance, and security.

Key Performance Indicators:

• Speed & Responsiveness: Ability to rapidly adapt to changing requirements and deliver updates swiftly.
• Timeliness: Meet agreed timelines and delivery milestones.
• Code Quality: Maintain high standards in software development, documentation, and testing.
• Efficiency: Optimal use of resources to deliver effective solutions.
• Standards Compliance: Adherence to internal and industry best practices.
• Team Leadership: Facilitate Agile development practices and foster team learning and cohesion.

• Bachelor's degree in Software Engineering
• Minimum English language skills at the Level B2
• Minimum 5 years of experience, including the responsibility to design and build complex microservices for a large organization.
• Deep knowledge of building microservices and understanding of architectural patterns such as orchestration and choreography (SAGA) using the Domain Driven Design approach.
• Develop, implement, and maintain scalable and loosely coupled microservices.
• Build and deploy high-quality APIs (REST / WebSockets based) to connect services and support external integrations.
• Expertise with containerization (Docker) and orchestration (Kubernetes).
• Strong programming skills in C#.
• Practical knowledge of the Red Hat OpenShift platform (RHOS). 
• Knowledge of Git Workflows.
• Ability to create automated, unit and integration tests.
• Establish and maintain CI/CD pipelines for microservices deployment.
• Implement monitoring, logging, and distributed tracing tools (e.g., Prometheus, Grafana, ELK, Jaeger) with a Service Mesh communication layer.
• Ensure system security through token-based authentication (JWT, OAuth2) and other measures.
• Deep knowledge of design patterns like Service Discovery, Circuit Breaker, and API Gateway (preferred KONG).
• Proficiency with cloud platforms (Azure, AWS) and associated tools.
• Hands-on experience with asynchronous messaging systems (Kafka based).
• Familiarity with distributed databases and data management strategies (SQL/ NoSQL).
• Proficient in implementing event-driven architecture (EDA) based on Kafka.
• Write clean, efficient, and maintainable code
• Practical knowledge of working in a CI / CD environment based on Azure DevOps.
• Experience in building observability for microservices.
• Knowledge of UML notation.
• Works independently and guide junior staff
• Writes specifications, concept documents, end-user and technical documentation; communicates effectively with stakeholders on technical and user requirements topics
• Well-developed interpersonal skills
• Ability to work in a team, demonstrating strong communication skills and a willingness to share knowledge.
• Previous experience working in an Agile team (SCRUM).
• SOLID understanding of best practices, processes and patterns in software development.
• Designing and implementing solutions based on microservices architecture.
• Creating technical documentation and conducting code reviews.
• Working with frontend and backend teams to deliver consistent solutions.
• Optimizing applications for performance and scalability.