Principal Engineer – Core

The world still has coverage blind spots. You could help eliminate them at Skylo.

Skylo has pioneered a standards-based approach to satellite connectivity. We connect smartphones and IoT devices directly to satellites. No special hardware, no entirely new networks. Just billions of existing devices, suddenly reachable anywhere on Earth. We're not building toward this future. We're already in it.

Our direct-to-device service is live on millions of activated devices across five continents, covering more than 72 million square kilometers, in partnership with leading satellite operators, mobile network operators, Tier-1 chipset makers, and OEMs worldwide. And we're just getting started.

At the heart of it all is Skylo's commercial NTN vRAN: a 3GPP standards-based, cloud-native platform that seamlessly bridges terrestrial and satellite networks. It's the infrastructure that makes true anywhere, anytime connectivity possible.

When you join Skylo, you'll work at the intersection of three markets reshaping how the world stays connected: mass-market consumer devices, automotive, and industrial IoT. Enabling people outdoors and critical workflows in the world's most remote places.

This is a rare chance to work on technology that matters, at a company that's already proving it works

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

• 15+ years of experience in mobile core network engineering, design, or architecture, preferably acquired within a mobile network operator or a core network vendor.
• Deep hands-on experience with 5G Core (SA) and EPC, including the service-based architecture (SBA/SBI) and 3GPP core specifications (e.g. TS 23.501, 23.502, 23.401).
• Hands-on experience with IMS architecture (P/I/S-CSCF, TAS, HSS) and end-to-end call flows for SMS delivery, VoLTE, and VoNR.
• Strong understanding of NAS, NGAP/S1AP, GTP, PFCP, Diameter, SIP, and HTTP/2 protocols.
• Proven ability to perform core network traffic forecasting, capacity planning, and dimensioning.
• Demonstrated expertise in defining KPI frameworks, baselines, and thresholds, and in driving performance optimisation.
• Experience managing core network vendors, including leading technical design reviews and acceptance testing.
• Excellent understanding of inbound and outbound roaming architectures and interconnect.
• Hands-on experience with cloud-native network functions and cloud technologies such as Kubernetes, Docker, and public cloud (AWS, GCP).
• Experience with Non-Terrestrial Networks (NTN) and 3GPP Rel-17+ NTN is highly preferred.
• Familiarity with Lawful Intercept, emergency services, and core network security is a plus.
• Excellent written and verbal communication skills for creating detailed technical documentation and presenting solutions to internal and partner audiences.
• Previous experience mentoring engineers or leading technical teams.

Skylo is hiring a Principal Engineer – Core to help fulfill Skylo’s mission of making satellite connectivity available to all. As a key member of the Network Design & Planning team, this individual will be the technical authority for Skylo’s core network and service layer, owning the architecture, design, capacity planning, and performance of our cloud-native 5G core, IMS voice and SMS services, and their integration with Skylo’s NTN RAN.

Your work will ensure our core network is reliable, scalable, and high-performance as we support millions of devices across consumer, automotive, and IoT use cases on the world’s first commercial direct-to-device satellite network.

• Own the end-to-end architecture and design of Skylo’s 5G core (5GC) and its interworking with EPC, including AMF, SMF, UPF, AUSF/UDM/UDR, PCF, NRF, NSSF and NEF functions.
• Act as the lead technical counterpart to our core network vendors, driving roadmap and feature requirements, design reviews, and release acceptance.
• Design and evolve IMS-based voice and messaging services (VoLTE/VoNR, SMS over NAS, SMS over IP, SMSC and IP-SM-GW interworking) for satellite-connected devices.
• Define how the core integrates with Skylo’s NTN vRAN, including NTN-specific requirements such as extended timers, long round-trip delay, mobility, tracking area design, and satellite/terrestrial roaming.
• Lead core network capacity planning and dimensioning, including traffic forecasting, subscriber growth modelling, and resource planning across cloud and on-prem deployments.
• Define core network KPI frameworks, baselines, and thresholds, and drive performance analysis and optimisation of registration, session, voice, and SMS success rates.
• Design roaming and interconnect architectures with MNO partners (S6a/S8, N32/SEPP, Diameter and HTTP/2 signalling, DEA/DRA, SMS interworking).
• Partner with Regulatory, Security, and Operations teams to ensure the core supports Lawful Intercept, emergency services, and network security requirements.
• Create technical specifications, high- and low-level designs, and engineering documentation for core network elements.
• Conduct proof-of-solutions and lab validation to assess new features, vendors, and architecture options.
• Drive continuous improvement loops with Operations & Implementation teams, including root cause analysis of core network incidents.
• Mentor engineers and provide technical leadership across the Network Design & Planning team.

• Competitive compensation packages including a stock option based equity program
• Comprehensive occupational health coverage
• 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 commercial, live 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 multi-national characteristics