Back End Developer

Backend Engineer – Product & Data

📍 Tokyo | Office-first Hybrid (1 day WFH per week)

Our client is searching for a skilled Backend Engineer to join a small, product-led engineering team at a fast-growing AI-powered SaaS company. This is a hands-on, ownership-heavy role where you'll build and improve the core backend systems that power a creative workflow platform used by leading brands across the region.

SUMMARY:

• Product-focused backend role with a data platform emphasis, building APIs, data models, background jobs, and AI integrations for a growing SaaS platform serving enterprise clients in the creative industry
• High-ownership, non-ticket-taking position where you'll take ambiguous product needs, break them into concrete backend work, and ship reliable systems end-to-end
• Collaborative cross-functional role working closely with product, frontend, AI, QA, and design teams in a small, high-trust engineering environment

RESPONSIBILITIES:

• Design, build, and maintain backend services including APIs, data models, background jobs, queues, permissions, and customer data boundaries that scale reliably with growing usage
• Build product data systems that make workflow events, approvals, asset history, and generated outputs reliable, searchable, and useful for reporting, reuse, and analytics
• Develop and maintain integrations with AI providers and model systems, including asynchronous job handling, retries, cost and latency tracking, error handling, and monitoring
• Improve observability, audit history, admin and debug views, and operational tooling so that engineers, QA, and product teams can investigate issues independently and efficiently
• Use production data, logs, metrics, and customer feedback to understand system behaviour post-launch and drive continuous improvement, while leveraging AI-assisted coding tools responsibly

REQUIREMENTS:

• Solid production backend experience building APIs, data models, background jobs, and distributed services, with strong Python proficiency and experience with frameworks such as FastAPI or equivalent
• Experience designing relational data models and working with production databases such as PostgreSQL, alongside practical knowledge of asynchronous workflows, retries, idempotency, and failure handling
• Hands-on experience with large-scale distributed systems using caching, streaming, queueing, or search infrastructure such as Redis, Kafka, Elasticsearch, or comparable tools
• Strong judgment around estimation, testing, operational risk, scalability, and maintainability, with careful handling of customer data, permissions, tenant boundaries, and audit history
• Fluent English required; Japanese and/or Chinese proficiency is a plus

Nice to Have:

• Data engineering or data platform experience including ETL/ELT, orchestration, analytics pipelines, or observability
• Experience with AI provider/API integration, model routing, asynchronous generation workflows, or model-output quality loops
• Familiarity with AWS (ECS/Fargate, SQS, RDS, S3), infrastructure as code (Terraform/OpenTofu), or workflow orchestration tools
• Backend development experience in TypeScript/Node.js or Go in addition to Python
• Background in multi-tenant SaaS, asset-heavy platforms, DAM/MAM, CMS, or creative workflow tools