Note: The job is a remote job and is open to candidates in USA. Horizon3.ai is a remote cybersecurity company focused on helping organizations identify, fix, and verify exploitable attack vectors through its NodeZero platform. The Senior Backend Engineer, Integrations will build and operate backend APIs, integration infrastructure, security-tool connectors, and MCP capabilities while supporting production reliability and mentoring engineers.
Responsibilities
- API Platform: evolving our internal GraphQL-federated API into a first-class, customer-facing product — with permissions, multi-account scoping, versioning, schema evolution, and documentation
- Integration Platform: building and operating a shared Integration Router so new connectors can be configured and declared rather than built from scratch, with reusable authentication, health checks, and workflow execution
- Security-Tool Integrations: shipping and maintaining integrations with the tools customers already use — CrowdStrike, Splunk, ServiceNow, Jira, Palo Alto, SentinelOne, and others in the SIEM, EDR, and ticketing ecosystem
- MCP Platform: expanding our customer-facing MCP server and agentic workflow capabilities across US, EU, and Australia production environments, enabling customers to build their own AI-powered workflows atop NodeZero data
- You'll also share on-call responsibility for a substantial production-observability footprint (Datadog, Kafka-triggered services, multiple environments), meaning you're not just shipping integrations — you're operating them
- Design and implement backend APIs in GraphQL — including federated subgraph development, schema evolution, and multi-account query scoping for MSSP and multi-subsidiary customers
- Build and extend the Integration Router: connector libraries, workflow configuration, secrets management, vendor adapters, and Kafka-triggered dispatch services
- Own production reliability for API and integration services: monitoring, alerting, deployment, vendor API drift, rate limits, retries, and safe failure handling
- Contribute to the MCP platform and OAuth proxy layer, including tool authentication and agentic workflow support
- Contribute production code that sets the standard for design quality, code quality, and operational rigor
- Collaborate with frontend engineers, product managers, and security-domain teams (particularly the Pentest Data Platform) to deliver integrated customer experiences
- Mentor junior and mid-level engineers on the team as it scales
- Ability to own and manage concurrent initiatives, with strong judgment in prioritization and time management
- Self-directed and driven — capable of conceiving and implementing solutions independently and as part of a team
- A strong desire to continuously learn new technologies in a fast-paced Agile environment
- Excellent analytical and problem-solving skills, with attention to detail and a high bar for quality
- Strong technical documentation ability to support an external developer audience
- Effective communication and collaboration across engineering, product, and design
- Interest in mentoring junior and mid-level engineers as the team grows
Skills
- Ability to own and manage concurrent initiatives, with strong judgment in prioritization and time management
- Self-directed and driven — capable of conceiving and implementing solutions independently and as part of a team
- A strong desire to continuously learn new technologies in a fast-paced Agile environment
- Excellent analytical and problem-solving skills, with attention to detail and a high bar for quality
- Strong technical documentation ability to support an external developer audience
- Effective communication and collaboration across engineering, product, and design
- Interest in mentoring junior and mid-level engineers as the team grows
- Bachelor's Degree in Computer Science, Computer Engineering, or a related field
- 7+ years of professional software engineering experience using modern object-oriented or functional languages (Python, Go, TypeScript, Java, Scala, C++, etc.)
- Experience building production applications on cloud platforms (AWS, Azure, GCP) using Docker and Kubernetes
- Expert proficiency in SQL, and experience with relational (PostgreSQL) and graph (Neo4j) database architectures
- Hands-on experience building GraphQL backends, including federated graph architectures and schema evolution patterns
- Experience designing and operating public API platforms — versioning, developer documentation, permission models, and multi-tenant access
- Experience building or operating an integrations platform with reusable connector patterns, event-driven workflows (Kafka or similar), and asynchronous execution
- Familiarity with OAuth/OIDC, service accounts, or machine identity patterns for programmatic API access
- Experience integrating with third-party security or IT platforms — SIEMs, EDR tools, ticketing systems (e.g., CrowdStrike, Splunk, ServiceNow, Jira, Palo Alto), or workflow automation platforms
- Experience with MCP, agentic frameworks, or other tool-protocol ecosystems
- Production reliability experience: observability tooling (Datadog or similar), on-call ownership, vendor API drift handling, and safe failure design
- Experience with customer-facing developer surfaces: CLI tooling, SDKs, or developer portals
Benefits
- Inclusive culture where everyone can thrive
- Numerous career development opportunities
- Remote and hybrid work models depending on role and location
- Equity package in the form of stock options for all full-time roles
- Health, vision and dental insurance for you and your family
- Flexible vacation policy
- Generous parental leave
Company Overview