Java Developer

About the role

Telecom mediation and rating platforms process billions of events every single dayusage records, network events, charging inputs, partner settlements, and more. These events must be collected, validated, transformed, enriched, and delivered with absolute accuracy and reliability. Even a small failure can lead to revenue leakage, incorrect billing, compliance issues, customer dissatisfaction, or fraud exposure.

This role ensures that every event flowing through BT’s networks is captured, processed, rated, and handed off correctly to downstream systems including Billing, Assurance, Fraud Management, and MIS platforms. The software you build and maintain directly protects BT’s revenue, operational integrity, and customer trust.

By ensuring highthroughput, faulttolerant, and secure mediation and rating processes, this role plays a pivotal part in enabling BT to bill accurately, detect anomalies quickly, make datadriven decisions, and deliver seamless customer experiences across all services. In short: you keep the business running, the revenue secure, and the network intelligent.

What you will be doing (Role Accountabilities)

• Technical Solution Delivery

Supports the implementation of technical solutions for internal and external customers across telecom mediation flows, resolving inter system issues and contributing within cross functional squads.

• Architecture & Technology Choices

Contributes to technical decisions, technology selection, and architecture direction for high performance mediation platforms, balancing immediate product needs with long term transformation.

• Software Design & Development

Supports the design and development of software components aligned with enterprise architecture and BT’s security standards.

• Continuous Learning & Technical Reviews

Undertakes code and design reviews to enhance proficiency and ensure alignment with software engineering principles and industry standards.

• Technical Specifications & Low Complexity Builds

Helps design technical specifications and develops software solutions for smaller or less complex initiatives, ensuring high quality delivery.

• Coding & Testing

Writes, tests, debugs, and reviews code under supervision, ensuring clarity and quality across engineering teams.

• Systems Integration

Integrates existing software products and resolves routine issues to ensure interoperability across diverse platforms and mediation layers.

• Defect Management

Monitors, troubleshoots, and corrects software defects to ensure platform reliability and service stability.

• Tooling & Automation

Supports the implementation, optimization, and maintenance of CI/CD pipelines and automation tooling that improve developer efficiency and accelerate delivery.

• Technical Roadmap Contribution

Supports delivery of a forward-looking technical roadmap that meets needs of engineering teams, operations, and business stakeholders.

• Engineering & Operational Excellence

Assists in defining and implementing metrics, processes, and continuous improvement initiatives to drive engineering maturity.

• Process Improvement

Contributes to refining and optimizing engineering ways of working within the software engineering domain.

What you’ll need to succeed (Skills & Experience)

Essential

• Expertise in Oracle OCOMC/ONM (v6/12/15), including cartridge development (EEs, PO components, Chains, Pipelines), NPL scripting for transformation, enrichment and correlation, CDR parsing, normalization and aggregation, file collection and distribution, high-throughput processing of multi-network event types, along with deployment, performance tuning and troubleshooting of mediation workflows.
• Strong background in Java/J2EE development, with experience in building and consuming REST APIs, multi-threaded processing and concurrency, along with proficiency in scripting (Shell/Python/Perl) for automation, tooling, and monitoring.
• Strong experience with WebLogic Application Server, including deployment and tuning of Java applications, JVM performance optimization, cluster management, JDBC tuning and thread pool configuration, along with troubleshooting of memory leaks, stuck threads, and connection-related issues.
• Hands-on experience with Netcracker Revenue Manager (NCRM/NC-RM) or equivalent rating ecosystems, including rating engine concepts, charge calculation flows, configuration of price plans, rating rules, usage types, event models
• Proven ability in debugging rating discrepancies and missing usage events, working with product catalog, tariff models, charging rules and discounts, ensuring seamless Mediation Rating Billing alignment, and supporting both batch and near-real-time rating workflows.
• Strong understanding of telecom network feed formats supporting Mediation and Rating systems, including Diameter (CCR/CCA), ASN.1-based CDRs, TAP/RAP/NRTRDE for roaming, 3GPP CDR formats (VoLTE, 5G, GTP’, SIP, CAMEL), IPDR, and vendor-specific formats (Huawei, Ericsson, Nokia, Cisco), along with the ability to decode, interpret, map, and troubleshoot raw network events.

Desirable

• 4–7 years of hands-on software development experience with strong proficiency in Java and related technologies
• Minimum 5 years of deep, practical experience in delivering OCOMC (Offline Mediation Controller) solutions, including cartridge development, NPL scripting, mediation and rating workflows, CDR processing, and production deployments.
• Proven experience in building, enhancing, and maintaining high volume mediation pipelines capable of processing billions of daily events with high accuracy, low latency, and strong fault tolerance.
• Strong exposure to telecom network event formats such as Diameter, ASN.1, TAP/RAP/NRTRDE, IPDR, and various 3GPP CDR structures, with the ability to analyse, decode, and map raw feed data.
• Hands on expertise with CI/CD pipelines using tools like Jenkins, Git, Maven, Nexus, or equivalent—covering build automation, artifact management, testing, deployment workflows, and rollback strategies.
• Solid experience in production system problem solving, including issue triage, deep-dive debugging, RCA creation, and working closely with operations to ensure system stability.
• Experience creating and maintaining monitoring and observability scripts (Shell/Python, Dyantrace), integrating with tools like Grafana, Prometheus, ELK, OEM, or custom dashboards to track throughput, error rates, latency, and system health.
• Demonstrated ability to work on complex, large-scale distributed systems, particularly those involving high-volume ETL flows into Billing, Assurance, Fraud, and MIS platforms.
• Experience collaborating in cross-functional squads, working in Agile environments, and contributing to improvement initiatives related to automation, performance tuning, and resiliency.