Principal Software Engineer, Agentic Data Platform

Horizon3.ai is hiring a Principal Software Engineer to provide technical leadership and hands-on architectural ownership for NodeZero’s database platform. The role defines database standards and architecture, guides scalable data storage and querying, and mentors engineers across teams.

Responsibilities:

• Technical Strategy: Define and drive the technical roadmap for the Database Platform in partnership with the Senior Engineering Manager and the broader Pentest Platform organization
• Architecture Leadership: Own the most complex database architecture decisions — schema design, partitioning strategies, migration patterns, and scalability approaches. Produce design documents that become the shared technical model for the team
• PostgreSQL Excellence: Be NodeZero's definitive expert on PostgreSQL at scale — query optimization, indexing, partitioning, replication, and connection pooling. Set the standards the team follows and catch the problems others miss
• Graph & Multi-model Data: Architect and guide the evolution of NodeZero's graph-based asset model — the data structure that represents how discovered hosts, services, credentials, and vulnerabilities relate to each other across pentests
• Schema Governance: Own schema design review processes. Ensure every migration is safe, reversible, and zero-downtime. Build the tooling and culture that treats schema changes with the same rigor as production code changes
• Mentorship & Bar Raising: Mentor P5 and P4 engineers through code review, design review, and pairing. Be the person on the team that raises everyone else's ceiling
• Cross-functional Influence: Partner with Data Ingestion, Asset Inventory, API Platform, and Security Research to define data contracts, query performance standards, and architectural guardrails that span the full data pipeline

Requirements:

• Deep, production-proven PostgreSQL expertise: query planner internals, advanced indexing (partial, expression, GiST/GIN), partitioning strategies, logical replication, vacuuming at scale, and connection pool tuning
• Experience architecting multi-tenant databases at scale: row-level security, tenant isolation, schema-per-tenant vs. shared-schema tradeoffs
• Experience with schema migration at scale in production systems: zero-downtime migrations, backwards-compatible schema evolution, and migration tooling (Flyway, golang-migrate, or equivalent)
• Familiarity with graph data models and graph databases (Neo4j, AWS Neptune) or graph-like query patterns in relational systems (recursive CTEs, ltree, adjacency list)
• Proficient in Go or Python — able to write production application code, not just SQL
• Demonstrated track record of defining database architecture at scale — from design doc to production — across multiple companies or teams
• Strong opinions on data architecture tradeoffs: normalization vs. denormalization, consistency vs. availability, OLTP vs. OLAP workload separation, and schema-first vs. schema-last design
• Able to reason about long-horizon schema design: what does this schema look like in two years, at 10× the current data volume, with three new feature teams writing to it?
• Able to communicate complex database decisions clearly in writing — for design docs, ADRs, and cross-team reviews — so engineers without deep DB expertise can understand and apply the reasoning
• Proven ability to drive database standards across multiple teams without direct reporting authority — including teams that are not the Database Platform team
• Experience establishing database engineering culture: schema review norms, migration safety standards, and query performance review processes
• Track record of growing engineers through code review, pair programming, and architectural mentorship — especially engineers who are strong in application code but earlier in their database expertise
• Background in cybersecurity data: vulnerability databases, network scan schemas, or attack surface management data models
• Experience with time-series databases (TimescaleDB, InfluxDB) in addition to relational
• Familiarity with data platform compliance requirements: SOC 2 Type II, FedRAMP data handling, or GDPR/CCPA
• Experience with analytical query patterns or BI/reporting workloads on operational data
• Contributions to open-source database tooling or PostgreSQL ecosystem projects