Software Engineer III

About the role

Monzo is building a modern banking platform to simplify financial management for millions of users. We are seeking experienced backend engineers to join our cross-functional squads and contribute to our mission of improving financial lives. You will own the design and implementation of critical backend services that power core banking capabilities and directly impact the financial wellbeing of our members. This role requires you to take ownership of complex problems from initial discovery through to production deployment and ongoing optimization. You will work closely with cross-functional partners to translate business requirements into robust technical solutions. Your contributions will help shape the future of how millions of people interact with their money on a daily basis. You will be responsible for ensuring the reliability, scalability, and security of the systems that underpin our platform.

Key facts

What you'll do

• Investigate and resolve intricate technical challenges across our distributed infrastructure and user-facing products.
• Architect and implement new features using strongly-typed languages such as Go, Java, C, or Scala to ensure system resilience.
• Partner with product managers, designers, data analysts, and engineers to define and deliver high-quality banking features.
• Collaborate within your squad to break down ambiguous problems and identify the most effective technical approaches.
• Write clean, maintainable code that integrates seamlessly with our existing systems built on AWS, GCP, Kubernetes, Docker, and Envoy Proxy.
• Contribute to the evolution of our data and messaging infrastructure leveraging Cassandra and Kafka for high-throughput processing.
• Support the development and maintenance of internal tools and user interfaces using React to improve developer and customer experiences.
• Champion best practices for open source contribution and uphold rigorous standards for distributed systems design.
• Participate actively in the standard interview process to ensure the best team match based on skills and evolving business needs.
• Mentor and elevate the technical capabilities of your peers through code reviews and collaborative problem-solving.

Requirements

• You possess strong professional experience in backend development with a proven track record of delivering scalable systems.
• You demonstrate a product-oriented mindset focused on data-informed decision-making to drive technical priorities.
• You show a strong ability to navigate ambiguity and thrive in a fast-paced, team-based environment.
• You have hands-on experience with strongly-typed languages such as Go, Java, C, or Scala in production settings.
• You have a demonstrated interest in building resilient, distributed software that can withstand real-world demands.
• You are comfortable working with complex infrastructure including AWS, GCP, Kubernetes, Docker, and Envoy Proxy.
• You have practical experience managing and integrating with data stores like Cassandra and messaging systems such as Kafka.
• No formal degree or specific qualifications are required to succeed in this role.

Nice to have

• Experience contributing to or building open source projects that are used in production environments.
• Familiarity with security and fraud detection systems within financial services contexts.
• Knowledge of modern frontend frameworks beyond React for building internal dashboards and tools.
• Background in high-availability financial systems that process transactions at scale.
• Understanding of compliance and regulatory considerations in digital banking platforms.
• Experience with performance optimization and debugging in large-scale distributed architectures.
• Exposure to machine learning or data analytics platforms for deriving insights from financial data.

Practical notes

• The interview process lasts approximately 4 weeks and includes an initial call, a take-home task or pair programming session, and a final round covering system design and behavioral topics.
• We encourage applications from all backgrounds regardless of whether you meet every listed requirement.
• Compensation includes a base salary dependent on experience plus performance-based incentive awards.
• Benefits include a yearly learning budget of 1,200 Euro for training, books, and conferences.
• Flexible working hours are supported to accommodate different working styles and personal commitments.
• This position is based in Barcelona, Spain, with a hybrid work model requiring 3 days per week in the office.
• Employment is offered as a full-time engagement with opportunities for long-term career growth.
• Candidates must be eligible to work in Spain and comply with local employment regulations.
• Travel requirements are minimal, with occasional in-person collaboration as needed for team alignment.
• Visa sponsorship may be considered for qualified candidates depending on specific circumstances and role requirements.
• Applications are reviewed on a rolling basis, and deadlines are determined by the needs of the hiring team.