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Location
In office (Sofia)
Seniority
Middle · 3+ years exp

First seen by Alion on Sep 23, 2026.

Overview
Company
Impact
Profile match
A1 Bulgaria is a telecommunications operator offering mobile and fixed services, the latest smartphones and devices, as well as digital, business and financial services, with online purchasing. Its Competence Delivery Center in Sofia hires AI architects, site reliability engineers, cloud optimization engineers, QA engineers and software asset management leads to support the group's operations. The company is headquartered in Sofia, Bulgaria.

Strength. Care. Growth

Did you know that A1 Bulgaria is working on international projects as well?
Our wide portfolio has long past the telecom services, and we are now offering digital solutions to millions of corporate, public, and private customers.
State-of-the-art technology, the latest innovations, and extremely talented professionals in various areas help us deliver the best-in-class products, services, and customer experience.

You’ll know A1 Bulgaria is the right place for you if you are driven by:

  • Opportunities to learn and build your career.
  • Meaningful work in a stable and fast-paced company.
  • Diversity of people, projects, and platforms.
  • A supportive, fun, and inspiring place to work.

Would you like to join us?

Borislav Kosatev is looking for a new team member.

We are looking for a skilled Network API Developer to design, develop, and maintain scalable APIs that power network services and integrations. You will work closely with network engineers, backend developers, and product teams to build robust interfaces that enable seamless communication across systems.

Your daily routine would include:

  • Design and develop RESTful and/or gRPC APIs for network services.
  • Integrate APIs with telecom/network infrastructure (5G, LTE, MPLS, SDN, etc.).
  • Build scalable, secure, and high-performance backend services.
  • Collaborate with network engineers to translate network capabilities into APIs.
  • Implement API versioning, documentation, and lifecycle management.
  • Ensure high availability, reliability, and monitoring of APIs.
  • Troubleshoot performance issues and optimize system performance.
  • Write clean, maintainable, and well-tested code.

We’ll know you can make it if you have:

  • Bachelor’s degree in Computer Science, Telecommunications, or related field.
  • 3+ years of experience in backend/API development.
  • Strong experience with Python, Java, Go, or Node.js.
  • Solid understanding of REST APIs, microservices architecture.
  • Experience with API gateways and management tools (e.g., Kong, Apigee).
  • Knowledge of network protocols (TCP/IP, HTTP, DNS).
  • Familiarity with containerization (Docker, Kubernetes).
  • Experience working with cloud platforms (Azure, AWS, or GCP).
  • Strong problem-solving and debugging skills.

Nice to Have

  • Experience in telecom environments (5G Core, IMS, OSS/BSS).
  • Knowledge of OpenAPI/Swagger specifications.
  • Familiarity with event-driven systems (Kafka, RabbitMQ).
  • Understanding of network automation and SDN/NFV.
  • CI/CD pipeline experience (GitHub Actions, Azure DevOps, Jenkins).

Our gratitude for the job done will be eternal, but we’ll also offer you:

  • Innovative technologies and platforms to “play” with.
  • Modern working environment for your comfort.
  • Friendly, ambitious, and motivated teammates to support each other.
  • Thousands of online and in-person learning opportunities to grow.
  • Challenging assignments and career development opportunities in multinational environment.
  • Attractive remuneration package.
  • Flexible working schedule and opportunity for home office.
  • Numerous additional goodies, including, but not limited to free A1 services, discounts, health insurance and services, sports center, childcare, team and family events, etc.

You want to learn more? See us in action in our A1 Blog.
Sounds good? Apply now!

Only shortlisted candidates will be contacted.

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