Contract
Backend & Infrastructure Engineer
We are looking for a contract engineer to own the backend, infrastructure, and security of enterprise business systems and our in-house AI SaaS, from design through implementation. Our PM covers the front end, so the role is to focus on APIs, data, platform, and authentication/authorization, and to ship production quality with a small team by pairing with coding agents such as Claude Code.
Remote or our Daikanyama office
Equivalent of 3+ days per week (negotiable)
Compensation discussed individually at interview
Technical Areas You'll Own
You will own the backend and infrastructure of our client projects and in-house SaaS. Starting from screen mockups, you validate requirements, data models, and authorization, then design and implement the APIs and production platform.
- Design, build, and codify GCP infrastructure (Cloud Run / Cloud SQL / Firestore / Pub/Sub / Secret Manager, Terraform, CI/CD)
- Authentication, authorization, and security design (Firebase Auth / Identity Platform, external IdP integration, roles and tenant isolation, audit logs, least privilege)
- Data integration and migration with core systems, SaaS, and other clouds, plus analytics foundations on BigQuery
- Backends for AI features (calling Vertex AI / Claude, prompt-injection defenses, execution logging and cost observability) and our agent-driven development foundations such as CLAUDE.md, hooks, subagents, and ADRs
What We Expect
- Able to design, build, and operate a production backend end to end in TypeScript (Node.js) or Python (guideline: 5+ years of professional experience)
- Able to build and operate production environments on GCP, including monitoring, incident response, and recovery
- Able to design data models and safe schema changes and migrations in a relational database such as PostgreSQL
- Able to design and implement OIDC / JWT and role-based authorization, and verify cross-tenant access control with tests
- Able to build IaC with Terraform and automate tests and deployments with CI/CD
- Uses coding agents such as Claude Code in daily development, runs verification and review of their output yourself, and records design decisions in writing to collaborate asynchronously
Nice to Have
- Backend build and operations experience on AWS or Azure (GCP is our default, but other clouds are very welcome)
- Cross-cloud authentication with Workload Identity Federation / OIDC
- External IdP integration via SAML / OIDC, or identity consolidation and record matching
- Building data and analytics foundations on BigQuery
- Integrating with core business systems or business SaaS such as Salesforce, or migrating legacy systems
- Building and operating LLM-based AI agents
Tech Stack
TypeScriptPythonNext.jsFastAPIGoogle CloudCloud RunFirebaseFirestorePostgreSQLBigQueryTerraformGitHub ActionsVertex AIClaude Code
Contract Terms
- Independent contractor (quasi-mandate), equivalent of 3+ days per week (negotiable)
- Remote or our Daikanyama office
- Production access and release decisions stay with KAGUYA employees
- Compensation, contract term, and expenses are explained at interview
Hiring Entity
- KAGUYA Inc.
- Inquiries: official@kgymoon.com