Software Developer

We are an AI-led platform-driven Digital Engineering and Enterprise Modernization partner combining deep technical expertise and industry experience to help our clients anticipate whats next. Our offerings and proven solutions create a unique competitive advantage for our clients by giving them the power to see beyond and rise above. We work with many industry-leading organizations across the world including 20 Fortune 50 companies and 4 of the 5 top banks in both the US and India and numerous innovators across the healthcare ecosystem.

Our disruptors mindset commitment to client success and agility to thrive in the dynamic environment have enabled us to sustain our growth momentum. Persistent has been recognized across top industry platforms for innovation leadership and inclusion. We have delivered 23sequential quarters of growth with $422.5M in Q3 FY26 revenue up 4.0% Q-o-Q and 17.3% Y-o-Y growth. Our 26500global team members located in 18 countries have been instrumental in helping the market leaders transform their industries. We won the 2025 ISG Star of Excellence Award for AI and Data Excellenceand were named a Leader in the Everest Group Talent Readiness for Next-generation Data Analytics and AI Services PEAssessment 2025.

Location: Pune India

Years of Experience: 8 to 12 Years

We are seeking an experienced R&D Engineer with a strong background in 4G and 5G protocol analysis to join our team. This role focuses on real-time parsing decoding and state tracking of mobile core network signaling. You will be responsible for implementing and maintaining protocol plugins that process live control-plane traffic from 4G LTE and 5G NR networks extracting structured events and session records for downstream analytics.

• Design implement and maintain 4G control-plane protocol parsers and state machines including S1AP GTP-C v1/v2 PFCP and SGsAP.
• Design implement and maintain 5G control-plane protocol parsers and state machines including NGAP and the full set of 5G Service-Based Interface (SBI) APIs.
• Parse and correlate multi-message procedures across protocols covering a wide range of telecom scenarios.
• Implement cross-protocol session correlation linking S1AP/NGAP UE context to GTP-C/PFCP sessions.
• Maintain protocol decoders in sync with evolving 3GPP Release specifications.
• Write unit and integration tests covering protocol edge cases and regression scenarios.
• Collaborate with the packet ingestion team on the upstream ZMQ message interface.
• Contribute to Helm chart and Docker packaging for Kubernetes-based deployment.
• Participate in code reviews architecture discussions and maintain technical documentation.

• Proficiency in modern C (C17 or later).
• In-depth knowledge of 4G/LTE protocols including S1AP GTP-C PFCP and SGsAP.
• In-depth knowledge of 5G/NR protocols including NGAP and the 5G Service-Based Architecture.
• Experience with multi-threaded event-driven protocol processing code.
• Solid understanding of state machine design patterns for stateful protocol tracking.
• Experience with Docker Git and CI/CD pipelines.

• Experience reading and implementing directly from 3GPP specifications.
• Knowledge of GTP-U and mobile user-plane data path.
• Familiarity with network slicing and VoLTE/VoNR call flows.
• Experience with network packet analysis tools like Wireshark.
• Familiarity with Prometheus and Grafana for metrics collection.

The ideal candidate will have a strong understanding of end-to-end telecom scenarios including attach handover roaming charging and authentication. You will be adept at translating these scenarios into accurate multi-protocol state machines that correctly correlate signaling across procedure boundaries. Your experience will be crucial in maintaining the integrity and performance of our mobile core network signaling analysis.

If you are passionate about telecommunications and have the required expertise we invite you to apply and join our innovative team.

Benefits:

• Competitive salary and benefits package
• Culture focused on talent development with quarterly growth opportunities and company-sponsored higher education and certifications
• Opportunity to work with cutting-edge technologies
• Employee engagement initiatives such as project parties flexible work hours and Long Service awards
• Annual health check-ups
• Insurance coverage: group term life personal accident and Mediclaim hospitalization for self spouse two children and parents

Values-Driven People-Centric & Inclusive Work Environment:

Persistent is dedicated to fostering diversity and inclusion in the workplace. We invite applications from all qualified individuals including those with disabilities and regardless of gender or gender preference. We welcome diverse candidates from all backgrounds.

• We support hybrid work and flexible hours to fit diverse lifestyles.
• Our office is accessibility-friendly with ergonomic setups and assistive technologies to support employees with physical disabilities.
• If you are a person with disabilities and have specific requirements please inform us during the applicationprocess or at any time during your employment

Lets unleash your full potential at Persistent- is an Equal Opportunity Employer and prohibits discrimination and harassment of any kind.