Infrastructure / Network Engineer

This full-time infrastructure and network engineering role supports an advertising platform through data-center and internal infrastructure. The private cloud is built in company data centers and handles traffic at a scale of several tens of Gbps. The position focuses mainly on network work while also supporting the broader infrastructure environment.

Daily responsibilities include designing, building, and operating networks centered on L3 switches and servers. The data-center network uses EVPN/VXLAN for L2 connections and BGP for L3 connections. The role also covers the design, operation, and management of external connections using dedicated lines and IPsec, analysis and optimization of high-volume traffic, infrastructure expansion projects, and feeding operational findings back into design improvements.

Depending on experience and interests, responsibilities may also include designing, building, and operating internal networks using L3 switches, L2 switches, and firewalls; managing wireless LAN from user authentication through access to the internet and data center; operating Windows servers; improving secure network environments for hybrid work; and solving internal user network issues. Security work includes strengthening monitoring and operations, creating security policies, and improving security across the infrastructure.

Required experience includes designing, operating, and building networks, servers, and firewalls, including L3 and L2 switches. Candidates should be able to identify issues independently and incorporate them into design and improvement work. Experience in either data-center infrastructure or internal infrastructure is welcomed. The role also seeks people who actively learn new technologies, value teamwork and communication, respond calmly to incidents, and can lead problems toward resolution.

The environment includes on-premises Linux, primarily Ubuntu, and SONiC; public cloud environments including AWS, GCP, OCI, and Azure; Kubernetes for container orchestration; Prometheus for monitoring; Ansible and Terraform for automation; and Argo Workflow and Argo CD for CI/CD. JAPAN AI, Cursor, and Claude are AI tools, with company support for the latest coding AI tools. Preferred experience includes BGP, EVPN/VXLAN, dedicated-line or IPsec connections, high-volume traffic, authentication platforms, Windows Server, zero-trust and security design, and monitoring tools such as Grafana and Prometheus.

The infrastructure organization consists of on-premises infrastructure, cloud infrastructure, and SRE teams. Each team has one manager and three members. The role can involve both data-center and internal infrastructure, and there are opportunities to work on infrastructure for overseas offices.

The position is based in Shinjuku, Tokyo. Work is generally on-site, with up to two work-from-home days per week.

The selection process is document screening followed by two or three interviews, with an SPI assessment and reference check required before the final interview.