★Backend Engineer | Data Center Services

• English ONLY OK

◆ Start-up Company

◆ Hybrid Work

◆ Own Products/Services

◆ Global Environment

◆ Annual salary: 8 million yen -14 million yen

【About the company】

・Data Center Development Support

・Data Center Maintenance and Operations

・Development and Operation of Cloud Services for Data Centers

【 Job Description】

Role overview

As a Backend Engineer, you will be responsible for the control-plane and gateway layer that connects the customer to our compute serving infrastructure. You will build and power the customer request lifecycle end to end, including handling requests via Cloudflare worker nodes, managing authentication and tenancy, validating requests, routing to the correct model endpoints, enforcing quotas and rate limits, and implementing reliability mechanisms to ensure platform stability under load. This layer is also key to achieving significant service performance latency through optimization. The goal is to build a backend that is fast, secure by default, abuse-resistant, and highly operable at scale.

You will collaborate with the inference and platform teams on developing the backend architecture. We expect you to be a central, hands-on contributor to the code stack, driving both the building and technical decision-making as an expert from the ground up. You will work closely with the President and engineering leadership on backend routing decisions that accurately reflect real capacity and failure domains, and ensure the system provides the necessary telemetry for rapid debugging.

Responsibilities:

● Architect Authentication & Billing: Build the OAuth/Billing layer, ensuring seamless tenancy management. You are responsible for Metrics & Billing Database, ensuring that every token is logged and billed.

● Manage the Control Plane: Engineer the backend services that handle user flows, API key generation, and workspace management. You ensure this layer remains highly available and decoupled from the high-traffic data plane.

● Data Persistence & Integrity: Manage the storage of data and design schemas that can ingest high-velocity telemetry from the edge without becoming a bottleneck.

● System Observability: Build the telemetry pipelines that aggregate logs from the Edge Gateway. Provide the tools that allow the team to debug why a specific routing decision was made or why a specific rate limit was triggered.

● Business Logic Implementation: Translate complex business requirements (customer tiers) into technical configurations that the Edge Traffic Engineer can enforce.

● API Design: Design and maintain the internal and external APIs that allow customers to programmatically interact with their accounts and settings.

【 Requirements】

Requirements

● Robust Backend Architecture: extensive experience with AWS ecosystems and server-side languages (Go, Python, or Java). You excel at building services that require high data integrity.

● Database Expertise: Strong proficiency in SQL and NoSQL database design, specifically for time-series data (metrics) and transactional data (billing/ledgers).

● Auth & Identity: Deep understanding of OAuth2, OIDC, and secure API key management lifecycles. Scalable API Development: Experience building REST or GraphQL APIs that serve as the control interface for complex infrastructure.

● FinOps/Billing Systems: Prior experience building usage-based billing systems or credit ledger systems.

【Working Time 】

09:00 ~ 18:00

【 Welfare 】

・Transportation Allowance: Partially provided (up to 15,000 yen per month).

・Social Insurance: Health insurance, Employees' Pension, employment insurance, and industrial accident compensation insurance.

・Overtime Allowance: Standard overtime pay provided.

【 Holiday 】

・Annual Holidays: 120 days.

・Work System: Full five-day workweek system.

・Annual Paid Leave: A minimum of 10 days or more provided starting from the 7th month of employment.