Senior Backend Engineer, External

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

Role overview

This Senior Backend Engineer will build and operate services that power external security assessment workflows. The work spans a Python API, long-running workflow orchestration, high-volume data processing, cloud data storage, graph-based interfaces, and the infrastructure beneath them. The engineer will own the reliability and performance of key services and partner with product and frontend teammates to ship usable capabilities.

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.

Requirements

• Strong backend engineering experience and the ability to own concurrent initiatives while making sound priority decisions.
• A reliability mindset for distributed and asynchronous systems, with methodical debugging and attention to failure recovery.
• Experience operating production services and taking responsibility for their performance and availability.
• Clear communication and technical writing skills for design documents, runbooks, and API documentation.
• Ability to work independently and collaboratively, learn new technologies, and partner with product and frontend colleagues.

Nice to have

Experience with workflow orchestration tools such as Prefect or Temporal, AWS data lakes, Kubernetes operations, GraphQL, and graph data models is relevant to the work described.

Benefits and work setup

The source lists medical, dental, and vision coverage, flexible vacation, parental leave, and stock options for full-time roles. It gives a base salary range of $199,750–$235,000 annually, with the final amount based on location, qualifications, experience, and skills.