Senior Backend Engineer — Scalable APIs & Data Orchestration

horizon3ai; United States; Remote; USD 200,000 - 235,000; Full time

Benefits offered by this job

Medical, dental, and vision coverage

Stock options

Job summary

horizon3ai is seeking a Senior Backend Engineer to build and operate services powering external security assessment workflows, including a Python API, long-running orchestration, data processing, cloud storage, and graph-based interfaces. You will own reliability and performance of key services, deploy on Kubernetes, and collaborate with product and frontend teams to ship usable capabilities.

Nice-to-have hands-on with Prefect/Temporal, AWS data lakes, GraphQL, and graph data models; the role

Qualifications

• Backend experience with concurrent systems and performance optimization.
• Ability to own multiple initiatives and make priority decisions.
• Experience operating production services with emphasis on reliability.
• Strong written communication for design docs and runbooks.
• Ability to work independently and with product/frontend teams.

Responsibilities

• Develop and maintain core Python API features with attention to performance, correctness, and maintainability.
• Build orchestration for long-running, concurrent workflows, including scheduling, retries, idempotency, state tracking, and recovery.
• Create and operate data processing and ETL pipelines, and contribute to cloud data lake architecture and query performance.
• Work with complex SQL and make safe production optimizations or refactors.
• Deploy and operate services on Kubernetes, contributing to release management, cluster operations, and capacity planning.
• Extend GraphQL and graph-based APIs, and maintain service observability, uptime, and scalability through metrics, tracing, alerting, and on-call work.

Skills

Backend engineering

Distributed systems

Production services

Communication

Independent work

Technical writing

Tools

Kubernetes

GraphQL

Graph databases

Job description

horizon3ai is seeking a Senior Backend Engineer to build and operate services powering external security assessment workflows, including a Python API, long-running orchestration, data processing, cloud storage, and graph-based interfaces. You will own reliability and performance of key services, deploy on Kubernetes, and collaborate with product and frontend teams to ship usable capabilities.

Nice-to-have hands-on with Prefect/Temporal, AWS data lakes, GraphQL, and graph data models; the role