Principal Engineer

We are looking for a Principal Engineer for a hybrid project, 2 days per week on-site, in Lisbon or Porto.

About the Role

You will enable product teams to deliver software more predictably, efficiently and safely by combining deep full-stack engineering expertise with practical leadership of an AI-enabled SDLC. The role operates across teams, builds reference implementations, solves complex cross-stack problems, strengthens engineering standards and helps Tech Leads adopt repeatable AI-assisted practices with appropriate human validation and governance.

You will act as an individual contributor with cross-team influence and no direct people-management responsibility, working closely with Tech Leads, Architects, Engineering Management, Product, Quality Engineering, Security, Data and Platform teams. You move between strategic direction and hands-on delivery depending on the problem and level of technical risk.

The ideal candidate influences through technical credibility, clear reasoning and collaboration. You remain hands-on and demonstrate proposed approaches in working code, balance engineering ambition with pragmatism, and communicate complex topics clearly to engineering, architecture, product and leadership audiences. You create leverage by enabling others and value security, transparency, traceability and accountability in the use of AI.

Main Responsibilities

Full-Stack Technical Leadership

• Define and drive the React Native technology roadmap, leading continuous improvement of the mobile app's performance, stability, security and release process.
  
• Provide expert guidance across frontend, mobile, backend, APIs, integrations, data persistence, cloud, CI/CD, observability and production operations.
  
• Lead technical discovery and engineering spikes for complex or high-risk initiatives.
  
• Build and maintain reference implementations that demonstrate approved patterns and accelerate adoption.
  
• Review designs and critical implementation decisions for scalability, maintainability, security, resilience and cost.
  
• Help teams diagnose complex production and cross-system issues when normal escalation paths are insufficient.
  

Engineering Excellence and Enablement

• Strengthen clean architecture, Domain-Driven Design, secure coding, automated testing, trunk-based development, CI/CD and infrastructure as code.
  
• Contribute to clear Definition of Ready and Definition of Done criteria, with focus on technical readiness, testability and operability.
  
• Create playbooks, templates, checklists and automation that make the preferred way of working easy to adopt.
  
• Coach Tech Leads and engineers through pairing, design sessions, code reviews, workshops and communities of practice.
  
• Promote pragmatic technical debt management, balancing delivery with long-term sustainability.
  

Architecture, Reliability and Security

• Implement architecture principles in working software and provide feedback to the Lead Architect.
  
• Champion API-first, event-driven and decoupled integration patterns when appropriate.
  
• Embed security by design, threat-aware engineering and privacy considerations into delivery.
  
• Advance application observability through structured logging, metrics, traces, alerting, service-level indicators and runbooks.
  
• Guide and help improve resilience, recoverability and operability of critical services.
  
• Support FinOps practices by guiding balanced cloud consumption and operational cost in design choices.
  

Requirements

Mandatory

• Proven experience as Principal Engineer, Staff Engineer, Senior Tech Lead or equivalent senior individual contributor.
  
• Strong frontend and mobile engineering expertise; production experience with React Native is a strong differentiator.
  
• Demonstrable full-stack experience from user experience and client applications through services, integrations, data and cloud operations.
  
• Experience influencing multiple teams without direct management authority.
  
• Delivery in complex enterprise environments with security, auditability, resilience and regulatory constraints.
  
• Evidence of introducing or scaling standards, reusable patterns or developer enablement capabilities.
  
• Frontend & Mobile: very strong — React, React Native, modern web architecture, accessibility and performance.
  
• Backend: expert in at least one stack — preferably .NET; Java or Node.js also relevant.
  
• APIs & Integration: strong — REST, OpenAPI, gateways, asynchronous messaging, Kafka.
  
• Cloud & Platform: strong — Microsoft Azure, containers, Kubernetes, serverless, infrastructure as code.
  
• Delivery Engineering: strong — Git, CI/CD, GitHub, Azure DevOps or Jira, SonarQube.
  
• Quality: strong — unit, integration, contract, end-to-end and performance testing.
  
• Operations: strong — observability, incident diagnosis, secure operations and resilience.
  

Mandatory AI-SDLC Experience (concrete examples required, not only tool familiarity)

• Hands-on use of AI coding assistants or agentic coding tools in real delivery (GitHub Copilot, Claude Code, Cursor or equivalent).
  
• Use of AI beyond code completion, including technical specification, tests, refactoring, review, documentation or incident analysis.
  
• Experience defining validation controls, review practices and guardrails for AI-generated outputs.
  
• Evidence of measurable change to delivery performance, quality, rework or developer productivity.
  
• Ability to distinguish safe, high-value AI use cases from activities requiring stronger human control.
  

Nice to Have

• Experience in financial services, payments, credit, banking or another regulated industry.
  
• Experience with customer-facing digital channels and high-volume transactional systems.
  
• Experience with platform engineering and internal developer platforms.
  
• Data: working to strong — relational and NoSQL stores, modelling, operational data and event streams.