IT Billing System Engineer (f/m/d) @ A1 Competence Delivery Center

Strength. Care. Growth

A1 Competence Delivery Center is a vital component of A1’s telecommunications business. Acting as an expertise hub, CDC is dedicated in delivering full range of high-quality IT, network, financial and other services to support A1’s operations across all OpCos, independent of location. 

Using the power of A1 Group and leverage synergies, CDC enables transparency of resources, key skills and knowledge expansion and personal career growth opportunities’ enhancement, paired with job stability. 

You will know we are 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.

Job Purpose:

End-to-end owner of carrier and wholesale billing operations, ensuring accurate, stable and compliant billing across multiple markets by driving workflow optimization, troubleshooting complex CDR/EDR-based issues, and coordinating cross-functional delivery with business stakeholders and software vendors.

Role insights:

• Take responsibility for operational activities: monitoring, incident handling, root‑cause analysis and stabilization of billing runs and batch/file processes.
• Perform business analysis on new wholesale products, traffic flows and charging concepts, ensuring they are correctly reflected in billing logic and mapping rules.
• Provide 2nd/3rd level support by analyzing, troubleshooting and resolving processing and mapping issues based on CDR/EDR data, logs and database checks.
• Act as key interface between business teams (wholesale / interconnection) and software vendors – from clarifying new requirements to testing and rolling out changes.
• Ensure performance, stability and compliance of batch‑ and file‑based billing processes (e.g. rerating, EDR extracts, month‑end runs) through effective monitoring, logging and auditability.
• Maintain clear and up‑to‑date technical and functional documentation (designs, mappings, runbooks, operations manuals, test descriptions).
• Operate and continuously improve carrier and wholesale billing workflows end‑to‑end (file ingestion, mediation, rating, reporting, invoicing) across multiple markets.

What Makes You Unique:

• Ability to read and understand Java code (e.g. to analyze existing billing logic, mappings or error situations); hands‑on Java development experience is an advantage but not mandatory.
• Expert skills in relational databases (Oracle, MSSQL) and SQL for analysis and performance‑critical investigations.
• Hands‑on experience in telecom billing/rating, ideally in wholesale, interconnect and/or roaming environments.
• Strong domain understanding of wholesale business models and charging, and the motivation to dive deep into the business logic.
• Solid experience in business analysis: gathering and challenging requirements, modelling processes and rules, and creating clear specifications for implementation.
• Knowledge of CDR/EDR structures and telecom use cases (voice, SMS, application SMS, MVNO, porting, home routing) is an advantage but not mandatory.
• Proven experience operating and troubleshooting batch/file processing chains in production, including alert handling on Windows Servers.
• Strong analytical and team player mindset, high attention to detail and structured work style in critical environments.
• Fluent in English; German is a plus.

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

• Innovative technologies and platforms to work 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. 

If you have any questions,  please do not hesitate to contact Svetlina Vazharova.