Senior Backend / Platform Engineer

About the role

Causaprima is hiring a Senior Backend / Platform Engineer in Madrid. You will own the platform its agents run on: an event-driven architecture, data pipelines, integrations with customer accounting systems, and the infrastructure that keeps everything reliable, auditable and fast.

Key responsibilities

• Build and maintain an append-only PostgreSQL event store with tamper-evident hash chaining, real-time event distribution, agent replay and recovery, and schema versioning.
• Set up cryptographic signature infrastructure: key management, signature verification on all agent events and approval chains for external actions.
• Implement a workflow constraint engine that verifies authorization before any external action (email, payment, API call).
• Manage PII vault and GDPR compliance: isolated, encrypted storage, right to erasure and data residency per region.
• Design multi-tenant data with row-level security and tenant isolation, and tenant-scoped LLM API keys.
• Configure attribute-based access control via Cerbos, with deterministic policy evaluation so LLMs never make auth decisions.
• Secure the Model Context Protocol endpoint with authentication, capability-based scoping per partner and rate limiting.
• Design PostgreSQL schemas, indexing strategies, performance tuning and read-replica topology.

Required profile

• 3+ years of experience with Python and/or TypeScript in production.
• 5+ years designing backend platforms for production systems.
• Strong systems design skills: thinking in boundaries, contracts, failure modes and scaling characteristics.
• Experience with policy-as-code authorization (Cerbos, OPA, Cedar or similar).
• Nice to have: production use of cryptographic primitives, event streaming platforms (Kurrent, Redpanda, Kafka), SOC 2 or GDPR compliance engineering, and a fintech or regulated-environment background.

Required skills

• Deep PostgreSQL knowledge: RLS, indexing trade-offs, event sourcing patterns, schema evolution.
• Application security architecture: encryption models, key management, auth patterns.
• Strong code review skills for security-sensitive AI-generated code.