Senior Backend Engineer (Integrations)

Join Horizon3's Platform Integration Team (PIT Crew) as a Senior Backend Engineer. In this role, you will lead the evolution of our internal GraphQL-federated API into a customer-facing product, build and operate a shared Integration Router, and maintain integrations with various security and IT tools. You will also contribute to the MCP platform and OAuth proxy layer, own production reliability for API and integration services, and mentor junior and mid-level engineers. This is a remote position with opportunities for growth and an innovation-driven culture.

• Conception et mise en œuvre d'API backend en GraphQL, y compris le développement de sous-graphes fédérés, l'évolution du schéma et la gestion des requêtes multi-comptes.
• Construction et extension de l'Integration Router : bibliothèques de connecteurs, configuration des workflows, gestion des secrets, adaptateurs de fournisseurs et services de dispatch déclenchés par Kafka.
• Responsabilité de la fiabilité de la production pour les services API et d'intégration : surveillance, alertes, déploiement, dérive de l'API du fournisseur, limites de taux, tentatives et gestion des échecs en toute sécurité.

• Bachelor's Degree in Computer Science, Computer Engineering, or a related field
• Interest in mentoring junior and mid-level engineers as the team grows
• Experience building production applications on cloud platforms (AWS, Azure, GCP) using Docker and Kubernetes
• Ability to own and manage concurrent initiatives, with strong judgment in prioritization and time management
• Strong technical documentation ability to support an external developer audience
• Effective communication and collaboration across engineering, product, and design
• 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
• 7+ years of professional software engineering experience using modern object-oriented or functional languages (Python, Go, TypeScript, Java, Scala, C++, etc.)
• 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 with MCP, agentic frameworks, or other tool-protocol ecosystems
• 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
• 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