Senior Core Network Engineer (HLR/HSS & SDM)

Help Us Build The Future of Travel At Airalo, we're making it easier for people to stay connected wherever they travel. As the world's first eSIM store, we help millions of travelers access affordable mobile data in 200+ countries and regions around the world. Today, we're a team of 400+ people across 60+ countries, building a product used by travelers every day. We've grown quickly, but we've worked hard to keep what matters: trust, ownership, and the freedom for people to do great work without unnecessary layers or bureaucracy. We're fully remote by design, genuinely global, and united by a shared mission to make travel simpler for everyone. Your Next Destination Location: Remote. Contract: Full-time, permanent. Benefits: Learn more about our benefits here in this link - https://airalo-public.notion.site/Benefits-25396a97ffca81fb9bc1f0be479f1be3?pvs=74 Languages: English is our main working language day to day, so you'll need to be comfortable communicating in it both in meetings and async.

As our Senior HLR/HSS Specialist, you are the guardian of our subscriber data and the architect of our roaming efficiency. You won't just manage databases; you will own the life-cycle of HSS/HLR templates that allow our MVNO to scale globally. Your expertise in Profile & Template Engineering is critical to our success in maximising COGS and margin through sophisticated Steering of Roaming (SoR) and Sponsor Roaming integrations.

Design and maintain HLR/HSS subscriber templates, ensuring precise configuration of roaming profiles, APN/PDN contexts, and Camel/Diameter triggers.

Collaborate with roaming partners to implement and refine SoR logic within the HLR/HSS, ensuring subscribers attach to preferred networks based on cost and quality.

Lead the technical deployment of Full MVNO profiles, managing specific QoS profiles and addressing (GTs, APNs) required for independent network operations.

Act as the primary technical point of contact for our System Integrators, auditing HLR/HSS configurations, reviewing change requests, and ensuring alignment with the 2026 roadmap.

Define and monitor critical HLR/HSS KPIs, including Location Update (LU) success rates and Diameter Transaction per Second (TPS) limits.

Deep technical mastery of MAP (SS7) and Diameter (S6a/S13) protocols; additional experience with VoLTE Roaming (S8HR) or SMSoIP rollout is a significant advantage.

Subscriber Mapping: Extensive experience with HLR, HSS, and UDM (User Data Management) in a multi-tenant or MVNO/E environment.

Practical experience with Multi-IMSI applets and the logic required to manage roaming through Sponsor IMSIs.

A solid understanding of GSMA IREG (IR series); familiarity with TADIG (TD series) and how HSS/HLR templates impact billing/settlement is preferred.

A "detective" mindset for troubleshooting complex signalling failures using tools like Wireshark or roaming-specific platforms (e.g., Mobileum, Roamware, or SIGOS).

Proven ability to manage technical projects with external System Integrators and roaming partners under tight deadlines.

Experience with 5G Unified Data Management (UDM) and Authentication Server Functions (AUSF).

Knowledge of Cloud Native Network Functions (CNF) and containerised core deployments.

Scripting skills (Python/Bash) for automating provisioning audits or log parsing.

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