Principle Platform Engineer - Backend Production Expert

**What this person will build:** * A single\-node on\-prem control plane deployable into a customer environment. Backend services for zones, assets, phantoms, alerts, response state, contracts, audit events and evidence generation. * APIs used by the portal, watchdog, connector layer and detection engine. * A PostgreSQL\-backed data model that can evolve towards the full Merkle Ledger, Trust Contract and Audit architecture. * A secure event pipeline from watchdog/connector signals through alert generation and response workflows. * The first hash\-chained audit log and evidence export primitives needed for enterprise review. **Core responsibilities** * Translate the Praesidius engineering specification into a pragmatic POC architecture and implementation plan. * Design and build backend services, APIs and internal module boundaries for the on\-prem control plane. * Own the PostgreSQL schema for assets, zones, phantoms, alerts, response state, policies, audit records and early trust\- * contract objects. * Build robust ingestion and processing paths for watchdog events, phantom interactions, connector data and response * actions. * Implement authentication, authorisation and RBAC foundations in collaboration with the CTO and frontend engineer. * Implement the first audit\-chain primitives: structured audit entries, predecessor hashing, chain head signing hooks and * evidence export APIs. * Create engineering standards for code quality, testing, error handling, logging, security review and documentation. * Work with the infrastructure engineer to package the control plane as an on\-prem Docker Compose deployment with a clear * path to Kubernetes later. * Work with the detection engineer to ensure alert and response workflows are deterministic, recoverable and explainable. * Support investor, design partner and Catapult/Innovate UK technical conversations where backend architecture or * implementation credibility is relevant. **Required experience:** * 8\+ years of professional software engineering experience, including ownership of production backend systems. * Expert\-level Python engineering experience. FastAPI, Pydantic, asyncio, SQLAlchemy or equivalent frameworks are highly * relevant. * Strong PostgreSQL experience, including schema design, migrations, indexing, transactional semantics and operational * performance. * Experience designing secure APIs and backend systems that need to be reliable, observable and auditable. * Experience with Docker\-based deployments and practical Linux systems engineering. * Strong understanding of distributed\-system trade\-offs, even though the first POC is intentionally single\-node. * Ability to write clear technical documentation, decision records and implementation plans. * Comfortable working in a small founding team where architecture, code, debugging, customer context and hiring input all overlap. **Desirable experience:** * Cybersecurity product experience in EDR, XDR, SIEM, SOAR, Zero Trust, identity security, network security or deception technology. * Experience implementing cryptographic data structures, signed records, PKI integrations or tamper\-evident audit systems. * Experience with Microsoft security ecosystems such as Defender for Endpoint, Microsoft Graph, Entra ID or Sentinel. * Experience building on\-prem enterprise software, appliances or products that run inside customer\-controlled environments. * Previous founding engineer or technical lead experience in an early\-stage company