Senior Backend Engineer

About the role

This position centers on owning a defined backend service inside one collective. You will shape production services from initial concept through launch and ongoing operation. Day to day work involves pairing with cross functional squads to advance products and infrastructure. You will hold responsibility for decisions and outcomes while working within a regulated bank. The role balances fast delivery with rigorous safety and control.

Key facts

Location options include Cardiff, London, or Remote within the UK. The engagement level is Senior Engineer (L50). The compensation band is £105,000 to £135,000, accompanied by incentive awards and standard benefits.

What you'll do

Design payment and account services with squad partners to achieve reliability and clarity. Architect backend components that scale while respecting existing patterns and constraints. Partner with product and data teams to define solutions that satisfy compliance requirements and user needs. Improve operational robustness by strengthening monitoring, alerts, and deployment safety for backend services. Review code and designs to keep interfaces consistent and understandable over time. Ship changes safely using test driven workflows and staged rollouts, with clear rollback plans. Coordinate with platform and security teams to align on standards, tooling, and incident response. Support collectives with data, observability, and experiments that inform product and infrastructure decisions. Explore and prototype new capabilities that push the boundaries of what the banking platform can achieve. Challenge existing assumptions and propose alternative approaches to solve complex problems. Translate ambiguous requirements into concrete technical specifications with squad stakeholders. Mentor other engineers by sharing knowledge and elevating the quality of backend designs across teams.

Requirements

You regularly write server code and understand how requests flow through systems at scale. You grasp distributed systems concepts such as idempotency, consistency, and production failure modes. You communicate clearly in both writing and speaking, adjusting detail level for engineers and non engineers. You enjoy working across teams, aligning on priorities, and recording decisions for others to use. You are comfortable making decisions and taking ownership of the outcomes in a regulated environment. You collaborate effectively with stakeholders who may have different levels of technical expertise. You value clarity, simplicity, and maintainability in the code you produce and review. You are proactive in identifying risks and proposing mitigations before problems occur in production.

Nice to have

Hands on experience with regulated financial services and related compliance topics is valued.

Skills and tools

Programming languages: Java, Kotlin, or Python. Data stores and messaging: SQL, NoSQL, and Kafka. Platforms and practices: Linux, Docker, Kubernetes, and CI pipelines.

Practical notes

Please note that Monzo is a banking app which helps you manage your everyday money. Monzo offers personal accounts, business accounts, joint accounts, and accounts for 16 to 17 year olds. A free kids account is also available, along with credit products and savings tools. Customers can invest and plan for pensions while using features such as early pay access and financial education. The company focuses on solving problems and removing complexity from traditional banking.

Team and impact

Around 650 engineers work across Monzo to design and build the in house banking platform. The bank operates multiple self governing collectives, each with different product and infrastructure responsibilities. These include Core Banking, Business Banking, Wealth, Borrowing, Growth, Payments, Platform, Fincrime, Security, and Expansion. Many collectives work on machine learning and artificial intelligence to fight financial crime and build smarter financial tools.

Open source and knowledge sharing

Monzo contributes to open source software wherever possible. Engineers are encouraged to learn more through internal blogs and public repositories. The company provides career frameworks and resources to support ongoing development.

How we hire

Roles are filled by matching skills, experience, preferences, and business needs. Engineers from varied backgrounds are welcome as long as they enjoy learning new things. No formal degree qualifications are required for engineering positions. The interview process is standard across collectives, with final placement based on fit for the role.

About the company

They'll be your partner and guide throughout the interview process. Initial Call (1 hour) You'll meet with one of our Senior Engineering Managers or Engineering Directors. They'll ask you about your previous experience, in particular people leadership, product delivery and technical leadership.