Senior VoIP & SMS Platform Lead

Rakuten Viber; Warszawa; On-site; PLN 180,000 - 260,000; Full time

Job summary

Rakuten Viber is seeking a Senior VoIP/SMS Engineer to join the Telco Operations team. You will lead engineering tasks, coordinate with carriers, and ensure high-availability voice and messaging services in a cloud environment.

The role requires 3+ years of hands-on VoIP/SMS experience, SIP/SMPP expertise, and strong English communication. You will engage with carrier partners and cross-functional teams to drive platform improvements and reliability.

Qualifications

• 3+ years of hands-on experience in VoIP/SMS operations or telecom engineering.
• Strong knowledge of SIP protocol, SMPP/HTTP messaging, and voice routing (Class 4/5 switches).
• Experience with network debugging tools (Wireshark, tcpdump, SIP trace analysis).
• Solid understanding of TCP/IP and networking fundamentals (switches, firewalls, routers, LAN/WAN/VPN).
• Experience with carrier interconnections: trunk setup, capacity management, and partner onboarding.

Responsibilities

• Take a tech-lead role within the team: coordinate engineering tasks, guide junior members, own escalation decisions, and represent the team in partner-facing communication
• Operate and maintain large-scale VoIP and SMS platforms in a cloud environment, ensuring high availability and optimal performance
• Provide Level II and Level III technical support for voice and messaging services, handling complex escalations from partners and internal teams
• Onboard new carrier partners: configure trunks, accounts, and routing for voice and SMS wholesale operations
• Investigate and resolve communication issues across the network: call quality, SMS delivery failures, routing anomalies, and protocol-level bugs
• Drive internal infrastructure projects: platform upgrades, legacy system decommissioning, CDR integration, and process automation
• Monitor, test, and evaluate network systems; recommend improvements to maintain or expand service levels
• Collaborate with Commercial, Routing, and Back-End teams to implement required platform changes
• Contribute to process improvements and automation of operational workflows
• Participate in anti-fraud and anti-spam efforts for Voice/SMS services, including traffic pattern analysis

Skills

VoIP operations

SIP protocol

SMPP/HTTP messaging

Voice routing

Carrier onboarding

Networking basics

SLA awareness

English skills

Interpersonal skills

Job description

Rakuten Viber is seeking a Senior VoIP/SMS Engineer to join the Telco Operations team. You will lead engineering tasks, coordinate with carriers, and ensure high-availability voice and messaging services in a cloud environment.

The role requires 3+ years of hands-on VoIP/SMS experience, SIP/SMPP expertise, and strong English communication. You will engage with carrier partners and cross-functional teams to drive platform improvements and reliability.