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Kazusa Tsubota
From Japan 06:57 AM (GMT+09:00)
$60,000/yr

Active 5 days ago


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AI Platform Engineer

Platform Engineer
Available for hire
Years of experience
7+ years
Experience level
Senior
Available from
08 Nov 2026

I am an AI Platform Engineer with 7+ years of software engineering experience across production AI infrastructure, cloud platforms, and backend systems. I connect GPU-based LLM serving with reliable production applications.

At ScalyX.ai, I designed vLLM inference infrastructure on Kubernetes/EKS, built AI Gateway and multi-model routing across LLM, speech, and vision workloads, and migrated 30+ tenants onto a shared EKS platform. These efforts reduced average monthly infrastructure costs by approximately 17% and GPU-related infrastructure costs by 15%. I also built real-time Whisper STT pipelines and production services using Python/FastAPI, RAG, embeddings, pgvector, and LLM tool calling.

My core tools include AWS, Kubernetes/EKS, Terraform, Docker, Helm, CI/CD, Prometheus, Grafana, OpenTelemetry, Jaeger, Python, TypeScript, NestJS, PostgreSQL, and Redis Streams. I focus on inference latency and throughput, observability, reliability, security, tenant isolation, and cost optimization.

I am based in Japan and looking for fully remote AI platform, AI infrastructure, production AI, or backend engineering opportunities with teams that can hire internationally.

Employment History

AWS AI Infrastructure / AI Production Engineer at ScalyX.ai Current 2025 - Now
Architected and migrated a multi-tenant AI-powered retail platform from per-tenant EC2 to a shared Kubernetes platform on AWS EKS, consolidating workloads across 30+ tenants and enabling demand-based autoscaling while reducing average monthly infrastructure costs by approximately 17%. Designed and optimized vLLM-based GPU inference infrastructure on Kubernetes/EKS, evaluating model characteristics, GPU requirements, workload patterns, and serving configurations to balance inference latency, throughput, availability, and cost. Implemented an AI Gateway and multi-model routing layer across LLM, speech, and vision workloads, routing requests based on workload and resource requirements and reducing GPU-related infrastructure costs by 15% while maintaining target service performance. Extended the AI platform to support real-time speech workloads, integrating Whisper-based STT with streaming audio pipelines and AI Gateway routing, with partial/final transcription handling for downstream LLM workflows. Built production AI services and workflows using Python/FastAPI, PostgreSQL, Docker, embeddings, semantic search, pgvector, RAG, and LLM tool calling, connecting retrieval, generation, and controlled backend actions. Designed scalable Kubernetes workloads using ALB, health checks, HPA, cluster/node autoscaling, and Helm, while standardizing infrastructure deployment with Terraform, Docker, ECR, and CI/CD. Built end-to-end observability with Prometheus, Grafana, OpenTelemetry, Jaeger, and CloudWatch, reducing average incident investigation time from 50 minutes to 30 minutes (40% reduction). Applied AWS/Kubernetes security and tenant-isolation controls using IAM, VPC/private networking, Security Groups, Kubernetes RBAC, Secrets Manager, and tenant-level access controls; performed synthetic load testing that validated aggregate request throughput of up to 10K requests/sec under controlled load while evaluating latency, concurrency, and GPU utilization.
Infrastructure / Backend Engineer at AllWeb3 2022 - 2024
Consolidated six backend services from six dedicated EC2 instances into a shared t3.medium environment using NestJS monorepo and Turborepo, preserving logical service boundaries while reducing the production EC2 footprint by 83% (6→1) and monthly EC2 cost from ~$45 to ~$30 (33%) for Alpha/MVP traffic. Designed and operated AWS production infrastructure across EC2 and Aurora RDS, right-sizing compute and database capacity against observed workload patterns rather than maintaining independent per-service capacity. Established a modular TypeScript/NestJS backend architecture with PostgreSQL and shared domain/API boundaries, collaborating with frontend engineers on feature specifications, API contracts, and implementation requirements while structuring services for future containerization and Kubernetes/EKS adoption. Automated non-production infrastructure scheduling with AWS Lambda and EventBridge, reducing development-environment runtime by approximately 70% (~50 vs. ~168 hours/week per instance) while preserving availability during engineering hours.
Full-Stack Engineer at StoreHub 2018 - 2021
Built commerce and POS capabilities using Next.js, TypeScript, React, Node.js, REST APIs, and PostgreSQL, supporting transaction, catalog, inventory, customer, and multi-location merchant workflows across a cloud SaaS platform. Designed reliable distributed and asynchronous systems using idempotent APIs, Redis Streams consumer groups, background processing, and business-rule validation for e-commerce, POS, inventory synchronization, order processing, and notifications. Optimized high-traffic product and inventory services with tenant-scoped Redis caching and PostgreSQL query/index/schema optimization, achieving a 90%+ cache hit rate and processing 1,000+ notifications/sec with <150ms p95 delivery latency.

Education

Bachelor of Engineering in Computer and Intelligent Systems Engineering at University of Malaya 2014 - 2018