Principal Backend Engineer

🚀 We’re on a mission to make money work for everyone.

We’re waving goodbye to the complicated and confusing ways of traditional banking.

After starting as a prepaid card, our product offering has grown a lot in the last 10 years in the UK. As well as personal and business bank accounts, we offer joint accounts, accounts for 16-17 year olds, a free kids account and credit cards in the UK, with more exciting things to come beyond. Our UK customers can also save, invest and combine their pensions with us.

With our hot coral cards and get-paid-early feature, combined with financial education on social media and our award winning customer service, we have a long history of creating magical moments for our customers!

We’re not about selling products - we want to solve problems and change lives through Monzo ❤️

📍London / UK Remote | 💰 This is a unique role, we're open to discussions on base salary + incentive awards tied to your performance + share options + benefits | Technology

Principal Engineer: L80 on our Engineering Progression Framework

About our Engineering Teams

We have around 600 engineers out of roughly 5,000 people in total - and we have big ambitions. There are many interesting challenges ahead, and we're happy for people to move between teams or to specialise, whatever you prefer. As an engineer here you'd be able to work directly with anyone across the company, and we run regular knowledge-sharing sessions so you’ll learn heaps about everything from how banks work to effective communication.

We contribute to open source software as much as possible. Our blog is a good place to learn even more about what we do.

Principal Engineer Responsibilities

A Principal Engineer at Monzo is a hands on engineering leadership (IC) position. As a Principal Engineer you’ll:

Partner with and guide Engineering and Product Leaders to shape the technical and product direction of Monzo, providing company-shaping leadership across collectives (100+ engineers) and driving alignment with company-wide priorities, owning problems that materially impact Monzo’s trajectory over the next 1-5 years.

Remain hands-on in both coding and architecture where it adds the most leverage, especially in complex, high-risk or novel areas.

Actively identifying high-leverage opportunities for Monzo and setting the direction of Engineering effort towards the most impactful outcomes.

Mobilise teams across Monzo around high-impact problems, creating clarity, alignment and momentum, injecting urgency, or slowing things down to ensure safety and long-term sustainability.

Lead and influence architectural direction for the most complex systems, driving consistency and reuse across domains, aligning local decisions with the broader system strategy.

Set and uphold a high bar for technical excellence across Monzo, identifying and driving improvements in quality, reliability and scalability, and fostering a culture where engineers hold each other to that standard.

Proactively mentor, sponsor and develop senior engineers and future leaders, multiplying your impact by enabling others to operate at a higher level.

What you’ll be using/ What you’ll be working on

We rely heavily on the following tools and technologies

Go to write our application code (there’s an excellent interactive Go tutorial here)

Cassandra for most persistent data storage

Kafka for our asynchronous message queue

Kubernetes and Docker to schedule and run our services

AWS for most of our production infrastructure and GCP for most of our data infrastructure.

React for internal Web dashboards

Feast for storing our features along a variety of tools to train and deploy models.

🤩We’d love to hear from you if…

You have a track record of leading complex, high-impact systems and driving technical direction across multiple teams, domains or business areas

You think in multi-year horizons to look around corners and build for the future, identifying opportunities before they p