Senior Core Network Engineer (HLR/HSS & SDM)

Stack

Responsibilities

• ▹Design and maintain HLR/HSS subscriber templates (roaming profiles, APN/PDN contexts, Camel/Diameter triggers)
• ▹Collaborate with roaming partners to implement and refine Steering of Roaming (SoR) logic
• ▹Lead the technical deployment of Full MVNO profiles (QoS profiles, addressing)
• ▹Act as primary technical point of contact for System Integrators, auditing HLR/HSS configurations and reviewing change requests
• ▹Define and monitor critical HLR/HSS KPIs, including Location Update success rate and Diameter TPS limits

Requirements

• ▹Deep technical mastery of MAP (SS7) and Diameter (S6a/S13) protocols
• ▹Extensive experience with HLR, HSS and UDM in a multi-tenant or MVNO/E environment
• ▹Practical experience with Multi-IMSI applets and Sponsor IMSI roaming logic
• ▹Understanding of GSMA IREG (IR series); familiarity with TADIG (TD series) preferred
• ▹Troubleshooting complex signalling failures using tools like Wireshark or roaming-specific platforms (Mobileum, Roamware, SIGOS)
• ▹Proven ability to manage technical projects with external System Integrators and roaming partners under tight deadlines

Nice to have

• ▹Experience with VoLTE Roaming (S8HR) or SMSoIP rollout
• ▹Experience with 5G Unified Data Management (UDM)

Soft skills

What we offer

• ▹Remote work
• ▹Generous PTO
• ▹Wellness and learning allowances
• ▹Annual Airalo Away company retreat

About the company

Airalo is the world's first and largest eSIM store, helping travellers stay connected seamlessly in over 200 countries and regions. The fully remote Networks team keeps over 20 million travellers connected reliably and securely at global scale.