Senior Backend Engineer, External

horizon3ai; United States; Remote; USD 140,000 - 190,000; Full time

Job summary

Horizon3 is a fast-growing remote cybersecurity company delivering NodeZero autonomous pentests and assessment automation. We seek a Senior Backend Engineer to own parts of our core API, data pipelines, datalake workstreams, and Kubernetes deployments on AWS.

You will drive performance, scalability, and reliability across distributed services. You will design and optimize large-scale workflows, contribute to GraphQL APIs, and collaborate closely with frontend, product, and design teams to

Qualifications

• 7+ yrs professional software engineering experience using modern OO or functional languages.
• Experience building workflow orchestration or distributed task processing systems (Prefect, Temporal, Airflow, Celery).
• Hands-on experience with high-throughput data processing and ETL pipelines.
• Experience building apps on AWS/Azure/GCP and using containers (Docker, Kubernetes).
• Strong communication and collaboration with product managers and designers.

Responsibilities

• Design, build, and maintain Python API features with performance in mind.
• Develop and operate workflow orchestration for large-scale workloads (Prefect/Temporal) including retries and state management.
• Build scalable orchestration across concurrent workflows with visibility into progress.
• Tackle complex SQL and optimize/refactor in production.
• Create data pipelines turning raw data into reliable datasets for querying.
• Contribute to AWS data lake architecture and ensure query performance.
• Deploy and manage services on Kubernetes and participate in release planning.
• Develop and extend GraphQL APIs to expose relationships in data.
• Own observability, uptime, and scalability with metrics and tracing.
• Collaborate with frontend, product, and design for a clear user experience.

Skills

Python

Go

Java

Kubernetes

AWS

SQL

GraphQL

TypeScript

Education

Bachelor's Degree in Computer Science or related field

Tools

Prefect

Temporal

Airflow

Celery

Docker

Kubernetes

Job description

Get to Know Us

Horizon3 is a fast-growing, remote cybersecurity company dedicated to the mission of enabling organizations to proactively find and fix and verify exploitable attack vectors before criminals exploit them. Our flagship product, the NodeZeroTM platform, delivers production-safe autonomous pentests and other key assessment operations that scale across the largest internal, external, cloud, and hybrid cloud environments. NodeZero has been adopted by organizations of all sizes, from small educational institutions to government agencies and Global 100 enterprises. It is used by ITOps/SecOps teams, consulting pentesters, and MSSPs and MSPs.

We are a fusion of former U.S. Special Operations cyber operators, startup engineers, and formerly frustrated cybersecurity practitioners. We're committed to helping solve our common security problems: ineffective security tools, false positives resulting in alert fatigue, blind spots, "checkbox" security culture, cybersecurity skills shortage, and the long lead time and expense of hiring outside consultants. Collectively, we are a team of learn it alls, committed to a culture of respect, collaboration, ownership, and results.

What You'll Do

As a Senior Backend Engineer on the External Attack team, you'll contribute to the full set of backend services that power NodeZero's external pentesting capabilities, from architecture and development through deployment and production operations. You'll own parts of our core API, data processing and ETL pipelines, datalake, graph, along with the container orchestration and cloud infrastructure beneath it all. You'll be accountable for the performance, scalability, and uptime of several of these services, and you'll be a key contributor to user-facing product launches and platform stability.

Responsibilities

• Design, build, and maintain features in our core Python API, with a focus on performance, correctness, and maintainability.
• Design, build, and operate workflow orchestration for large-scale, long-running workloads using tools such as Prefect or Temporal, including scheduling, retries, idempotency, state management, and failure recovery.
• Build orchestration that scales reliably across many concurrent workflows, with clear visibility into progress, failures, and throughput.
• Comfort reading and untangling unfamiliar, complex SQL, and the judgment to optimize or refactor it safely in production.
• Build and operate high-throughput data processing and ETL pipelines that turn large volumes of raw assessment data into reliable, queryable datasets.
• Contribute to datalake architecture on AWS, including storage layout, partitioning, schema evolution, and query performance.
• Deploy and manage services on Kubernetes, and take part in cluster operations, release management, and capacity planning.
• Develop and extend GraphQL and graph-based APIs that let product components and customers explore complex relationships in their data.
• Own the observability, uptime, and scalability of the services you build, including metrics, tracing, alerting, and on-call participation.
• Partner with frontend engineers, product managers, and designers to turn backend capabilities into a clear, responsive user experience.
• Contribute to systems architecture decisions and write design docs that help the team move quickly with shared understanding.
• Collaborate with frontend team members to present data in a clear and user-friendly format, enhancing the product's user experience.

What You'll Bring

• The ability to own and manage concurrent initiatives, with sound judgment in prioritization and time management.
• A self-driven approach: you can conceive and implement solutions on your own and with a team.
• A reliability mindset for distributed work: you design for retries, partial failure, and recovery, and you debug asynchronous systems methodically.
• A strong desire to keep learning new technologies in a fast-paced Agile environment.
• Excellent analytical and problem-solving skills, clear communication, and attention to detail.
• A bias toward operational ownership: you care how your code behaves in production
• Strong technical writing for design docs, runbooks, and API documentation.
• Effective collaboration with designers, developers, and product managers.

Required Education / Experience

• Bachelor's Degree in Computer Science, Computer Engineering or related field.
• 7+ yrs professional software engineering experience using modern object-oriented or functional languages (Python, Java, Go, Scala, C++, TypeScript, etc).
• Experience building and running workflow orchestration or distributed task-processing systems in production (for example Prefect, Temporal, Airflow, Celery, or similar).
• Hands-on experience designing and building high-throughput data processing systems and ETL pipelines.
• Experience building applications on cloud computing platforms such as AWS, Azure, GCP, using container technologies such as Docker and Kubernetes.