Senior Full Stack .NET Developer

2 weeks ago

Kallithea, Attica, Greece Opencomm SA Full time €30,000 - €60,000 per year

About Us

We are a modern telecommunications company committed to delivering cutting-edge solutions to our clients. As we grow our software development team, we're looking for a
Senior .NET Developer
who combines deep backend expertise with a passion for learning and applying
AI-powered services
.

About the Role

As a
Senior .NET Developer
, you will architect and develop high-performance services using
C#
, with a strong emphasis on
multithreading
,
asynchronous programming
, and
RESTful APIs
. Bonus points if you bring
AI orchestration experience
—especially with
Semantic Kernel
—but if not, you must be
eager and capable to learn.

You'll collaborate with a cross-functional team on building services that integrate with state-of-the-art AI APIs, creating real-time applications that push the boundaries of what's possible in telecom.

Key Responsibilities

  • Design and develop scalable, reliable services in
    .NET Core
  • Work on
    multithreaded
    ,
    high throughput
    ,
    asynchronous applications
  • Build and consume
    RESTful APIs
    for both internal modules and external AI services
  • Integrate AI-powered capabilities such as:
  • -
    LLMs
    (OpenAI, Azure OpenAI, etc.)
  • -
    Speech-to-Text (STT)
    services (Google Speech, Azure Speech, etc.)
  • -
    Text-to-Speech (TTS)
    services (AWS Polly, Azure TTS, etc.)
  • Lead the architectural design of new features and services
  • Conduct code reviews, mentor junior developers, and enforce clean architecture standards
  • Create and maintain database models and business logic
  • Collaborate on system performance tuning, debugging, and robust error handling
  • Translate requirements and user stories into functional, production-ready code

Desired Skills & Experience

  • 5+ years
    of hands-on experience with
    .NET Core/C#
  • Solid understanding of
    OOP
    ,
    async/await
    , and
    multithreaded
    service design
  • Deep understanding of architectural patterns:
    MVC
    ,
    Clean Architecture
    ,
    SOLID principles
  • Proficiency with
    REST APIs
  • Experience with
    unit/integration testing
    ,
    Git
    , and
    CI/CD pipelines
  • Ability to produce
    clean
    ,
    maintainable
    ,
    production-grade code

Bonus Points For

  • Proficiency with
    Entity Framework
    (or similar ORM),
    SQL
  • Hands-on experience with
    Microsoft Semantic Kernel
    or similar AI orchestrator
  • Knowledge of
    prompt engineering
    ,
    AI design patterns
    or
    RAG architecture
  • Familiarity with
    vector databases
    (Pinecone, Qdrant, FAISS, etc.) and
    semantic search
  • Experience building
    chatbots
    ,
    virtual assistants
    , or
    LLM-powered workflows
  • Curiosity and fast learning ability in the
    AI ecosystem
  • Background in
    telecom
    or real-time data processing environments
  • Experience with
    containerization
    (Docker/Kubernetes) is a plus
  • Experience with
    cloud platforms
    (Azure, AWS, or GCP) is a plus

Why Join Us?

  • Be part of a forward-thinking company integrating AI into telecom solutions
  • Work on exciting projects that merge web development with AI innovations
  • Competitive salary package based on experience
  • Hybrid working model for better work-life balance

If you're passionate about creating modern web applications, eager to work with AI-driven technologies, and ready to take ownership of challenging projects — we'd love to hear from you

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