Tech Lead / Solution Architect

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Tech Lead / Solution Architect - Backend, Workflow Engine, SSO, Observability, QA based in Spain. This is a senior technical leadership opportunity focused on designing and delivering the backend foundation of a new Legal OS MVP. You will own architecture decisions across backend services, workflow orchestration, security, observability, and quality engineering. The role combines hands-on engineering with solution architecture, requiring you to turn complex requirements into reliable, production-ready systems. You will design resilient workflows with strong guarantees around retries, idempotency, consistency, auditability, and failure recovery. You will also establish secure SSO and permissions models while building comprehensive observability and automated QA practices. The environment is highly autonomous, project-based, and focused on delivering a pragmatic MVP with a strong emphasis on reliability and security. This role is ideal for a senior backend engineer or architect who enjoys owning technical direction and building robust systems from the ground up. Accountabilities

• Own backend architecture and technical direction, translating product goals into scalable and maintainable production solutions.
• Define the architecture boundaries and minimal service contracts, including APIs and event-driven interfaces required for the MVP.
• Design the core data model, including Matter IDs, mapping rules, and idempotency keys to ensure reliable and consistent processing.
• Build and define the workflow layer with retry and backoff strategies, dead-letter handling, replay capabilities, deduplication, and resilient failure recovery.
• Establish security architecture covering SSO, role-based permissions, access controls, and secure secrets management.
• Implement comprehensive audit trails that clearly capture who performed an action, what occurred, when it happened, and why, supported by correlation IDs and distributed tracing.
• Design and implement observability practices covering structured logging, metrics, tracing, system health, and operational troubleshooting.
• Establish robust QA gates covering integration, end-to-end, and regression testing for critical workflows such as document delivery, deadlines, and audit functionality.
• Collaborate with relevant stakeholders to make pragmatic architectural decisions and ensure solutions are ready for production.
• Contribute hands-on code and technical implementation while maintaining a strong focus on reliability, security, maintainability, and operational excellence.

• Senior-level experience in backend engineering and solution architecture, with a proven track record of shipping production systems.
• Strong understanding of distributed systems and failure modes, including retries, idempotency, consistency, race conditions, deduplication, and recovery strategies.
• Hands-on experience designing and implementing backend services, ideally using Python and frameworks such as FastAPI.
• Strong knowledge of relational databases, particularly PostgreSQL.
• Experience with queues and event-driven architectures using technologies such as NATS, RabbitMQ, Kafka, or comparable platforms.
• Strong understanding of APIs and integrations with external platforms and services.
• Experience implementing OIDC, SSO, authentication, authorization, roles, permissions, and secrets management.
• Practical knowledge of observability and monitoring technologies such as OpenTelemetry, Prometheus, ELK, or similar platforms.
• Strong experience with integration, end-to-end, and regression testing, including integrating automated QA into CI pipelines.
• Familiarity with Docker and modern software delivery practices.
• Ability to independently make architecture decisions, define technical contracts, and translate ambiguous requirements into actionable solutions.
• Strong analytical and problem-solving skills, with a proactive approach to identifying reliability, security, and scalability risks.
• Excellent communication and collaboration skills, with the ability to explain technical decisions clearly to both technical and non-technical stakeholders.
• Comfortable working autonomously in a project-based environment and taking ownership from architecture through implementation and delivery.

• 100% remote working arrangement, with a preference for candidates working within European/CET time zones.
• Full-time or part-time engagement options.
• Freelance/project-based working arrangement.
• Opportunity to shape the architecture of a new Legal OS MVP from the ground up.
• High level of technical ownership and autonomy.
• Hands-on work across backend engineering, workflow automation, security, observability, and QA.
• Opportunity to build reliable, security-focused systems designed for real-world legal workflows.
• Start as soon as possible, with workload and engagement level agreed upon based on project needs.