Principle Platform Engineer - Backend Production Expert

What this person will build:

• A single-node on-prem control plane deployable into a customer environment.
• 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.
Backend services for zones, assets, phantoms, alerts, response state, contracts, audit events and evidence generation. 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.
  
  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., 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.