Senior Backend & Platform Engineer (Quality, Security & Reliability)

The Cloud Strategy Office develops financial intelligence, governance, and decision-support products for internal-cloud service providers and private- and public-cloud buyers. We help stakeholders improve cost, pricing, investment, quality, and multi-cloud strategy through reliable data products and strong financial partnership.

The Cloud Strategy Office is expanding into a production financial platform that supports internal-cloud service providers and cloud buyers. The roadmap includes budget and forecasts simulation, internal unit-price analysis, automated reports, depreciation and asset detail, vendor-cost detail, anomaly tracking, and multi-cloud usage and cost data. We need a hands-on senior engineer who can build the backend, make integrations reliable, and own engineering quality as AI-assisted delivery increases. This person will ensure that plausible but incorrect changes are detected and corrected before they create financial, security, or reliability risk.

Build, modify, test, and operate production backend services and APIs in Python

Own integrations with source systems, including interface contracts, authentication, reliable ingestion, validation, and failure handling

Act as the technical lead and quality authority for the engineering work while remaining an individual contributor with no people-management responsibility

Review human-written and AI-generated changes, identify plausible but incorrect behavior, and make or guide the necessary corrections

Keep technical debt low through simple architecture, clear boundaries, automated tests, refactoring, documentation, and removal of obsolete paths

Own CI/CD and automated quality controls, including code review automation, testing, dependency and container controls, and secure delivery practices

Improve reliability, performance, observability, incident response, and recovery as the platform and user base scale

Work closely with the Financial Data & Analytics Engineer to provide trustworthy source data and stable product boundaries for business data modelling

Deliver roadmap capabilities with finance specialists, internal-cloud service providers, the Cloud Center of Excellence, data specialists, and internal-cloud buyers

Use English for cross-functional communication, documentation, technical review, and decision records

You will join a newly formed, small cross-functional team in the Cloud Strategy Office. The team combines engineering and finance expertise and works directly with the people who provide and buy Rakuten’s internal and public-cloud services. This role reports to the hiring manager and leads technical standards without line-management authority.

The current environment includes Python, SQL, Flask, BigQuery, Google Cloud Storage, Parquet, DuckDB, HTML, CSS, JavaScript, Cloud Run, Cloud Run Jobs, Docker, Terraform, Jenkins, pytest, Ruff, mypy, and AI-assisted development tools. Candidates do not need prior experience with every named tool, but they must be able to become productive in this environment quickly.