Senior Backend Engineer, Data & App Platform

Get to Know Us Horizon3 http://Horizon3.ai is a fast-growing, remote cybersecurity company dedicated to the mission of enabling organizations to proactively find, 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 IT Ops/SecOps teams, consulting pentesters, and MSSPs and MSPs. We are a fusion of former U.S. Special Operations cyber operators, startup engineers & operators, and formerly frustrated cybersecurity practitioners. We're committed to helping solve our common security problems: ineffective security tools and 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. As a remote first company, we require minimum 25Mbps consumer grade broadband connection. WHAT YOU'LL DO The Pentest Data Platform (PDP) team owns the shared data platform that ingests NodeZero output from ephemeral operations and delivers it into durable storage, increasingly, in near real time. The team's core mandate is to build a scalable, event-driven architecture that makes operational insights available in near real-time, not just after it finishes. PDP is a foundational, platform-oriented team whose outputs power core user experiences within the NodeZero security platform. PDP owns the data contracts and internal data services that everything else is built on top of. NodeZero generates large volumes of structured pentest telemetry: hosts, findings, attack paths, credentials, weaknesses, and relationship graphs. PDP is responsible for turning that raw telemetry into coherent, durable, and queryable records that downstream teams can build on reliably at enterprise scale. The team is driving the largest architectural change in Horizon3's history: reworking pentest data processing from a batch-centric monolith into a real-time, event-driven microservice architecture. There is existing code to understand, live customers to protect, and hard distributed-systems problems to solve, all at the same time. In this role, you will: - Own event-driven pipelines end to end — design, build, and operate streaming services that ingest, distribute, and process pentest operation results, including streaming and batch ETL, aggregation services, schema migrations, and replayable processing. - Solve real-time asset identity problems — work on asset matching, asset counting, and cross-operation reconciliation, including reducing false splits and overcounting, improving matching explainability, and making asset identity available while an operation is running rather than only after completion. - Evolve the data model — manage durable SQL-backed storage (PostgreSQL), drive schema evolution with zero-regression fidelity, and ensure data correctness, idempotency, and reliable reprocessing and failure handling. - Drive enterprise scalability — own database performance, connection pooling, resource management, and platform reliability for a system that must handle hundreds of thousands of hosts per customer. - Translate batch logic into streaming designs — convert batch business logic (finding enrichment, attack path analysis, host and identity correlation and other core requirements) into streaming designs without regressing fid