Job Title: Senior VoIP Engineer

Location: Lagos, Nigeria (On-site)

Employment Type: Full-time

Company: Esdiac

About Esdiac

Esdiac is a leading software development company with deep expertise in telecommunications and data-driven solutions. We design and build innovative products that power next-generation voice, video, and data communication systems. Our mission is to deliver seamless, secure, and high-performance communication tools that connect people across the globe.

Role Overview

We are seeking a highly experienced Senior VoIP Engineer to own the design, deployment, and operation of our carrier-grade voice platform. You will run a multi-region SIP infrastructure spanning Lagos and the United States, manage interconnects with carriers and wholesale partners, and build the software and automation that keeps it reliable at scale. The ideal candidate combines deep VoIP and networking expertise with strong cloud engineering and software development skills, and is comfortable moving between packet captures, Kubernetes manifests, and application code in the same day.

Key Responsibilities

• Architect, deploy, and operate FreeSWITCH and Kamailio based voice infrastructure across multiple regions and data centers.
• Design and maintain SIP trunking and interconnects with carriers, wholesale providers, and DID suppliers, including routing, least-cost routing, and failover.
• Engineer the network layer for real-time media: NAT traversal, RTP/SRTP, TLS, QoS, and cross-border latency optimization.
• Build and maintain cloud infrastructure on AWS (EKS, VPC, networking, IAM) using infrastructure-as-code, with a focus on high availability and disaster recovery.
• Develop tooling and services around the voice platform — call routing logic, CDR pipelines, billing integration, provisioning APIs, and monitoring.
• Implement call-quality monitoring and observability (MOS, jitter, packet loss, ASR/ACD, PDD) and lead root-cause analysis of voice incidents.
• Secure the platform against toll fraud, SIP scanning, and abuse; manage SBC policies, rate limits, and access controls.
• Support the mobile and backend teams on SIP client integration, WebRTC gateways, and push-based call delivery.
• Own on-call for voice infrastructure and drive incident response, postmortems, and reliability improvements.
• Document architecture and runbooks, and mentor engineers on VoIP and networking practices.

Requirements

• Bachelor's or Master's degree in Computer Science, Telecommunications, Electrical Engineering, or related field.
• 7+ years of professional experience building and operating VoIP systems in production.
• Expert-level knowledge of SIP, SDP, RTP/RTCP, SRTP, DTMF, and codec negotiation (Opus, G.711, G.729).
• Hands-on production experience with FreeSWITCH and Kamailio or OpenSIPS, including dialplan design, ESL/Lua scripting, and dispatcher/routing modules.
• Strong networking foundation: TCP/IP, UDP, NAT, firewalls, BGP/peering concepts, VLANs, QoS, and packet analysis with Wireshark, sngrep, or tcpdump.
• Solid cloud engineering experience on AWS — EKS/Kubernetes, VPC networking, load balancers, Terraform or equivalent, CI/CD.
• Software engineering proficiency in at least one of Kotlin, Java, Go, Python, or C/C++, with experience building services that integrate with telephony platforms.
• Experience with carrier interconnects, SIP trunk provisioning, DID management, and number portability workflows.
• Experience with observability stacks (Prometheus, Grafana, Homer/SIPCapture, ELK) applied to voice traffic.
• Strong problem-solving, incident management, and communication skills; comfortable working across time zones.

Preferred Skills

• Experience deploying voice infrastructure in African markets and managing interconnects with regional carriers.
• Familiarity with WebRTC gateways, session border controllers, and STIR/SHAKEN.
• Experience with Kafka or similar streaming systems for CDR and event processing.
• Knowledge of telecom regulatory and compliance requirements (NCC, FCC, GDPR).
• Contributions to open-source VoIP projects or relevant certifications (AWS, CCNP, CKA).

What We Offer

• Competitive salary and performance bonuses.
• Professional growth opportunities, including training and certifications.
• Flexible work arrangements and a collaborative team culture.

To Apply: Send your CV and a short cover letter to info@esdiac.com with the subject line: Senior VoIP Engineer – Lagos.