Senior Backend & Cloud Infrastructure Engineer

Sekai is building an AI-powered consumer platform for creating, remixing, and playing interactive content. The Backend & Cloud Infrastructure Engineer will build and scale backend services and APIs, support AI/LLM workloads, and manage AWS infrastructure to keep the platform scalable, reliable, and efficient.

Responsibilities:

• Own the architecture, development, and evolution of core backend services. Write high-quality code in Python / Go, and lead design reviews and code reviews
• Design and build high-performance, highly available RESTful / gRPC APIs that serve high-traffic consumer features and AI / LLM workloads
• Design and tune async task processing and message queues (Kafka, Celery, SQS, etc.) for throughput and data consistency
• Plan, build, and govern our AWS infrastructure (ECS / Lambda / RDS / S3 / CloudFront / VPC, etc.), and drive Infrastructure as Code with Terraform or similar tools
• Build and improve monitoring, logging, and alerting (Datadog, CloudWatch, Sentry). Keep alerts actionable and production stable
• Lead incident troubleshooting, on-call response, and postmortems. Keep improving capacity planning, autoscaling, and disaster recovery
• Own cloud cost and security: remove idle resources, enforce least-privilege IAM, and manage multiple accounts and internal network access
• Turn shared business logic into reusable services, middleware, and internal tools, and improve CI/CD so the team ships faster and more reliably

Requirements:

• 5+ years of backend development experience, including at least 2 years in cloud or infrastructure work
• Strong proficiency in Python or Go, with hands-on experience building large projects on frameworks such as FastAPI, Django, or Gin
• Solid knowledge of core AWS services, with production experience in architecture, operations, and cost optimization
• Experience with Docker and ECS / Kubernetes, and with IaC tools such as Terraform
• Strong MySQL / PostgreSQL schema design and performance tuning skills
• Familiar with Redis, Kafka, Nginx, and other common middleware
• Strong production debugging skills, with on-call and postmortem experience
• Good communicator who can own a project end to end, from design to launch
• Backend experience with AI / LLM applications, such as model integration, agent systems, or managing LLM cost and reliability
• Experience supporting large-scale, high-traffic consumer products
• Multi-cloud (AWS + GCP), cloud migration, or account consolidation experience; familiarity with BigQuery or similar data platforms
• Knowledge of networking and security, such as VPN / zero trust and compliance