Senior Site Reliability Engineer

Senior Site Reliability Engineer - Tech Lead

¥9M–¥15M

Hybrid (2 days WFH/week) | Tokyo

Japanese: Professional Speaking ability (N1)

A fast-growing marketing-tech company is hiring a Senior SRE to be the technical anchor behind its AI-powered B2B SaaS platform as it scales into the enterprise. This is a pure technical leadership role, no people management, where you'll own reliability architecture and build an AI-first SRE and Platform Engineering culture from the ground up.

What you'll own

• Define and monitor SLI/SLO and error budgets; lead incident response and root-cause analysis
• Build monitoring and logging foundations; drive capacity planning and cost optimisation
• Harden CI/CD pipelines and embed on-call and SRE practices across the org
• Lead tech selection and architecture; raise the whole team's engineering bar

Environment & stack

• Backend: Python, FastAPI
• Cloud & infra: AWS (ECS, Lambda), Docker, Terraform
• Data: MySQL, BigQuery, MongoDB, OpenSearch, Redis
• Observability: Prometheus, Datadog
• CI/CD: GitHub Actions · DDD & Clean Architecture
• Full company-funded AI coding tools

Must-haves

• 5+ years enterprise SaaS development
• 3+ years cloud infrastructure (AWS/GCP/Azure) with hands-on IaC
• Experience building monitoring / logging platforms
• Business-level Japanese (N1)

Nice to have: incident management, high-availability / high-security systems (e.g. finance / payments), on-prem network design.