Senior Backend & Cloud Infrastructure Engineer

Sekai•San Francisco, CA

2d•Remote

About The Position

Sekai is building an AI-driven consumer platform for creating, remixing, sharing, and playing interactive content. The company is remote-first and is a Series A startup backed by Khosla, a16z, and Mayfield, with $30 million raised to date. The Backend & Cloud Infrastructure Engineer will build and scale the systems behind Sekai, working across backend development and cloud infrastructure. The role involves building high-performance APIs, supporting AI/LLM workloads, and ensuring the platform is scalable, reliable, and efficient. The engineer will own work end to end, from designing core backend services to optimizing AWS infrastructure and improving system performance in a fast-moving startup environment.

Requirements

At least 5 years of backend development experience, including at least 2 years of cloud or infrastructure work.
Strong proficiency in Python or Go and hands-on experience building large projects with 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 or Kubernetes, and with Infrastructure as Code tools such as Terraform.
Strong MySQL or PostgreSQL schema design and performance-tuning skills.
Familiarity with Redis, Kafka, Nginx, and other common middleware.
Strong production debugging skills, including on-call and postmortem experience.
Good communication skills and the ability to own a project end to end, from design to launch.

Nice To Haves

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 experience (AWS and 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.

Responsibilities

Own the architecture, development, and evolution of core backend services.
Write high-quality code in Python or Go, and lead design reviews and code reviews.
Design and build high-performance, highly available RESTful and gRPC APIs for high-traffic consumer features and AI/LLM workloads.
Design and tune asynchronous task processing and message queues such as Kafka, Celery, and SQS for throughput and data consistency.
Plan, build, and govern AWS infrastructure, including services such as ECS, Lambda, RDS, S3, CloudFront, and VPC.
Drive Infrastructure as Code using Terraform or similar tools.
Build and improve monitoring, logging, and alerting using tools such as Datadog, CloudWatch, and Sentry, keeping alerts actionable and production stable.
Lead incident troubleshooting, on-call response, and postmortems.
Improve capacity planning, autoscaling, and disaster recovery.
Manage cloud cost and security, including removing idle resources, enforcing least-privilege IAM, and managing multiple accounts and internal network access.
Turn shared business logic into reusable services, middleware, and internal tools.
Improve CI/CD so the team can ship faster and more reliably.