Principal Software Engineer - SIP/SDP Signaling

About Skylo

Skylo is a global Non-Terrestrial Network service provider based in Mountain View, CA, offering a service that allows smartphone and IoT cellular devices to connect directly over existing satellites. 

Skylo’s direct-to-device service is now live across four continents, with more than 50 million square kilometers of coverage, in partnership with multiple satellite operators, mobile network operators (MNOs), Tier-1 chipset makers, and OEMs. Devices connected over satellite are managed and served by Skylo's commercial NTN vRAN, featuring a 3GPP standards-based cloud-native base station and core. Skylo provides anywhere, anytime connectivity solutions that seamlessly roams between terrestrial and satellite networks. Our focus is on enabling connected services for people outdoors and connected workflows across three main verticals: mass-market consumer devices, automotive, and industrial IoT. 

This role is located in Bangalore, India where we are onsite 3 days a week in the office. 

Summary Of How You Will Impact Skylo

Skylo is hiring a Principal Software Engineer to help fulfill Skylo’s mission of making satellite connectivity available to all. This person will play a key role in Architecting and implementing Voice Gateway Solution across NB-IOT. The right candidate will combine a depth of technical knowledge with a passion for creating best-in class Voice Gateway software solutions.  

How You Will Contribute 

• Lead the design and development of Voice Services across NB-IoT, focusing on signaling and media session setup.
• Build and optimize scalable Voice Gateway Servers supporting thousands of SIP sessions and integrating with MNO Session Border Controllers and IMS networks.
• Define and implement CSFB-SS7-based registration (I1 protocol) and 3G voice call flows for integration with NTN carriers and 3GPP IMS Core networks.
• Develop and integrate third-party SIP/SDP protocol stacks and interworking functions for CSFB-I1 and SIP/SDP.
• Focus on optimizing voice services for low-bandwidth networks.
• Ensure security best practices in software development and deployment.
• Collaborate with platform engineering teams to iterate and deploy application components efficiently.
• Work closely with QA to define, test, and automate component, performance, and functional testing scenarios.
• Establish disciplined development and deployment processes to ensure high-quality, timely software delivery.
• Use tools like Jira, Jenkins, and GCR/GKE for build and deployment workflows.
• Act as a self-managing engineer, collaborating with cross-functional teams to streamline processes and enhance feature development.

What We Look For 

• 8+ years of experience in professional software development, focusing on OOP and distributed microservices.
• Bachelor’s or Master’s degree in Computer Science, Engineering, or a related field.
• Expertise in CSFB, I1, SIP Signaling, 3GPP IMS standards, and VoIMS solutions.
• Proficient in using SIP stack for UE proxy client and B2B server development.
• Skilled in tools like SIPP and FreeSWITCH for test environment setup.
• Programming experience in C/C++ or Java, with strong SQL database design and query optimization skills.
• Knowledge of stream processing systems (e.g., GCP Pub/Sub, Kafka) and REST API/network protocol design.
• Experience building stable, scalable server components and distributed systems for horizontal scaling.
• Hands-on expertise in Kubernetes, Docker, Jenkins pipelines, and GCP.
• Quality-focused with experience using test frameworks.
• Collaborative team player with excellent communication skills.

What We Offer

With employees working across three continents, Skylo is proud to be an equal opportunity employer dedicated to building an inclusive and diverse workforce. Our worldwide and inclusive culture encourages a flexible approach to work, and we also offer an attractive range benefits such as: 

• Competitive compensation packages including a stock option based equity program 
• Comprehensive benefits including medical, dental, vision, retirement plan
• Monthly allowances for wellness and education reimbursement
• A generous time off policy, holidays, and the opportunity to temporarily work abroad
• Once in a lifetime opportunity to be a part of developing and running world’s first software-defined direct-to-device satellite network and service 
• Access to world-class team and talent across tech domains: software, hardware, chipsets, telecom, satellite and network virtualization 
• Open, transparent, inclusive culture that blends the Silicon Valley, Nordic and South Asia characteristics

EEO Statement
Skylo is an equal-opportunity employer and we celebrate diversity. We do not discriminate on the basis of race, religion, color, ancestry, national origin, caste, sex, sexual orientation, parent or caregiver status, political affiliation, gender, gender identity or expression, age, disability, medical condition, pregnancy, genetic makeup, marital status, or military service consistent with applicable federal, state, and local laws.

We are also committed to providing reasonable accommodations for qualified individuals with disabilities and disabled veterans in our job application procedures. Please let us know if you need assistance or accommodation due to a disability.