---
title: 'Backend Engineer III at Referrals Only'
canonical: 'https://feeny.ai/job/backend-engineer-iii-referrals-only-cardiff-london-or-awnc2afx215n'
type: 'job'
last_seen: '2026-09-07'
---

# Backend Engineer III at Referrals Only

- **Company:** Referrals Only
- **Location:** Cardiff London OR, United Kingdom
- **Work type:** remote
- **Posted:** 2026-07-13
- **Last confirmed live:** 2026-09-07
- **Apply:** https://job-boards.greenhouse.io/monzoreferrals/jobs/8059751

## Job description

📍London or UK Remote | 💰 [Engineer III](https://monzo.com/documents/engineering-progression-framework-v4-1.pdf)

Compensation: £85,000 - £110,000 + Incentive Awards tied to your performance + [Benefits](https://monzo.com/careers/) | [Technology](https://monzo.com/blog/technology)

About our Engineering Teams:

We have around 650 engineers across Monzo who design and build our in-house banking platform. We have big ambitions for the future, and technology plays a big role in creating a bank our customers want, so engineers at Monzo collaborate across disciplines to solve interesting challenges throughout the company.

These range from the products our customers use everyday to underlying infrastructure, security, payments and finance, customer operations, financial crime, and data, to name just a few areas. As a bank, there is scope for impact across a huge number of opportunities.

## How we work 💻

Our main tech hub is in London, but our engineers live everywhere in the UK— from Brighton to the Western Isles. We value meeting in person but we don't have a mandated requirement on office attendance, even if you're nearby. We believe you'll do your best work if you are where you want to be. If you live outside of London and we ask you to come into the office, Monzo will support you with the costs ✨

Our offices are naturally social, especially Tuesdays, Wednesdays and Thursdays, which happen to line up with our twice-weekly Monzo lunches & treat Thursdays 🍽️

Teams also schedule time together often for work and play – in or around the office, or online.

Set up a work schedule that delivers impact and fits your life:

At Monzo, we value connections, flexibility, and wellbeing. We keep our meetings during core hours to stay connected and believe in maintaining work/life balance.

You’ll be empowered to manage your work in a way that suits you and your team, giving you the freedom for children drop-offs and pick-ups, walking your dog or adventurous cat, avoiding peak commuting times or gym slots, appointments, or supporting your family in an emergency 🕣✨

If you prefer to work part-time, we'll make this happen whenever we can - whether this is to help you meet other commitments or strike a great work-life balance.

Work the way that works for you with Monzo! 💼

You should apply if:

- you have strong experience working on the backend of a technology product
- you want to be involved in building a product that you (and the people you know) use every day
- you have a product mindset: you care about customer outcomes and you want to make data-informed decisions
- you’re comfortable working in a team that deals with ambiguity
- you’re interested in distributed systems and writing resilient software
- you have some experience with strongly-typed languages (Go, Java, C, Scala etc.).
- you think you’d enjoy the kind of work we’re doing

We're on the look out for L40 Engineers at the moment, you can read more in our [Engineering Progression Framework](https://monzo.com/documents/engineering-progression-framework-v4-1.pdf) you will be interviewed across the whole framework, so if you're not sure what level you're aiming for chat to your recruiter!

Not ticking every box? That’s totally okay! Studies show that women and people of colour might hesitate to apply unless they meet every single requirement. At Monzo, we’re dedicated to creating a diverse and welcoming team. If you’re passionate about this role and keen to learn and grow with us, we encourage you to apply— even if you don’t have everything thats listed just yet. Drop us your application, we’d love to hear from you!

What you’ll be working on:

We hire very technically agnostic so whilst we use the below technologies we do not expect prior knowledge, you will be fully supported in our organised onboarding to get up to speed in the below:

- [Go](http://golang.org/) to write our application code (there’s an excellent interactive Go tutorial [here](https://tour.golang.org/welcome/1))
- [Cassandra](http://cassandra.apache.org/) for most persistent data storage
- [Kafka](http://kafka.apache.org/) for our asynchronous message queue
- [Kubernetes](http://kubernetes.io/) and [Docker](https://www.docker.com/) to schedule and run our services
- [Envoy Proxy](https://www.envoyproxy.io/) for RPC
- [AWS](http://aws.amazon.com/) for most of our production infrastructure and[GCP](https://cloud.google.com/) for most of our data infrastructure
- React for our public web apps and internal tools
- We also have physical datacenters with actual cables to connect to various third parties

The Interview Process:

Our interview process involves three main stages:

- Initial Call
- Take home task or pair coding exercise
- Final interview: including a system design and a behavioural interview

Our average process takes around 4 weeks but we will always work around your availability.

One of our engineers has written a detailed blog on their experience through this process, for extra details, hints and tips please see [here](https://monzo.com/blog/2022/03/23/demystifying-the-backend-engineering-interview-process).

What’s in it for you:

💰 £85,000 - £110,000 base salary + Incentive Awards tied to your performance

✈️ We can help you relocate to the UK

✅ We can sponsor visas.

📍This role can be based in our London office, but we're open to distributed working within the UK (with ad hoc meetings in London).

⏰We offer flexible working hours and trust you to work enough hours to do your job well, at times that suit you and your team.

📚Learning budget of £1,000 a year for books, training courses and conferences

➕And much more, see our full list of benefits [here](https://monzo.com/careers/)

We're usually always hiring for Backend Engineers, so there's no closing date for this job.

#LI-Remote

## About Referrals Only

## Company Overview
- **One-liner**: Marqeta is the world’s first modern card issuing platform, providing open APIs that enable businesses to create, manage, and scale customized payment card programs.
- **Entity Type**: Public (Ticker: MQ on NASDAQ)
- **Headquarters**: Oakland, California, USA
- **Founded**: 2010
- **Founders**: Jason Gardner (Founder & Executive Chairman)

## Core Business
- **Primary industry**: Financial Technology (Fintech) — Modern Card Issuing & Payment Solutions
- **Target customers**: B2B; serves a wide range of industries including digital banking, on-demand delivery, buy now, pay later, expense management, retail, and workforce payments. Customers include Square, DoorDash, and other high-growth fintech and enterprise companies.
- **Mission or purpose statement**: To simplify payments and enable any company to deliver delightful payment experiences natively, powering more flexible, engaging, and innovative payment products.

## Products & Services
- **Modern Card Issuing Platform (SaaS/API)**: Fully open API platform that allows developers to launch new credit and debit card programs with speed, flexibility, and scale. Supports instant wage access, embedded finance, and custom card products.
- **Compliance & Risk Management (Service)**: Integrated fraud detection, spend control, and compliance tools to ensure high levels of security and uptime.
- **Global Expansion Capabilities (Platform)**: Certified to operate in over 40 countries across the US, Europe, and Asia, enabling businesses to scale globally.

## Market Standing
- **Valuation/Market Cap**: As a public company, market cap fluctuates. As of mid-2026, Marqeta is a publicly traded company valued in the multi-billion dollar range (exact figure varies with market conditions).
- **Key Metric**: Annual Revenue — $383 billion+ in total volume processed in 2025; 80x volume growth since 2017; 99.99% platform uptime in 2025.
- **Notable Investors/Partners**: Key customers include Square (Block), DoorDash, and other leading fintech and enterprise firms. Partners include issuing banks, networks (e.g., Visa, Mastercard), and card fulfillment providers.
- **Growth Signals**: Recognized as a CNBC Disruptor (top 50 in 2021 award); consistent expansion into new geographies (EU, UK, Asia); continued hiring across multiple departments and regions (US, Canada, UK).

## Competitive Advantages
- **First-mover & category leader**: Marqeta defined the modern card issuing category with its open API platform, giving it a decade-plus head start over competitors.
- **Scalability & reliability**: Proven track record of 99.99% uptime and handling massive transaction volumes (80x growth since 2017) — critical for enterprise customers.
- **Deep integration with major networks**: Pre-existing relationships with Visa, Mastercard, and issuing banks shorten time-to-market for customers.
- **Developer-first approach**: Open APIs and developer tools make it easy for engineering teams to build custom payment experiences quickly.

## Strategic Focus
- **Global expansion**: Continuing to expand its certified operations into new countries (currently 40+) to serve multinational customers.
- **Embedded finance & new use cases**: Driving adoption in instant wage access, embedded finance, and enterprise expense management.
- **AI & automation**: Investing in AI-powered fraud detection, risk management, and product automation (e.g., hiring for Principal Security Engineer, Product & AI; Lead Product Manager, Enterprise AI & Automation).
- **Platform stability & security**: Maintaining industry-leading uptime and security compliance as core differentiators.

## Why Work Here
- **Culture & values**: Marqeta emphasizes a culture of “Simplify and Innovate,” “Solve for the Customer,” “Do What’s Right,” “Make it Count,” and “Win as a Team.” Employee Resource Groups (ERGs) include BlackCard, HOLA, RepresentAsian, Desi, MQ-Proud, Vets@MQ, Women’s Group, Parents’ Group, and Marqetaglots.
- **Remote/hybrid policy**: Many roles are remote (US, Canada, UK), with some positions based in Oakland, CA or London, UK. The company supports flexible work arrangements.
- **Notable perks & engineering culture**: Fast-paced, purpose-driven environment; strong focus on developer experience and open APIs; opportunities to work on cutting-edge payment infrastructure at massive scale. The company invests heavily in early career talent and internal mobility.
- **Award-winning workplace**: Recognized as a top workplace (e.g., CNBC Disruptor) and offers a collaborative, inclusive environment.

## Sources
1. [Marqeta About Us](https://www.marqeta.com/company/about-us)
2. [Marqeta Careers Page](https://www.marqeta.com/company/careers)
3. [Marqeta Homepage](https://www.marqeta.com/)
4. [Greenhouse Job Board](http://job-boards.greenhouse.io/marqeta)
5. [MQ Referrals Job Board](https://job-boards.greenhouse.io/mqreferrals/jobs/7743043)

## Other roles at Referrals Only

- [Product Manager, Subscriptions](https://feeny.ai/job/product-manager-subscriptions-referrals-only-barcelona-0jkx6zdsjnj7) — Barcelona, Spain
- [Fraud Investigator, Overnight Team](https://feeny.ai/job/fraud-investigator-overnight-team-referrals-only-united-kingdom-weayv59k72r1) — United Kingdom
- [Lead Market Researcher](https://feeny.ai/job/lead-market-researcher-referrals-only-cardiff-london-or-83qyn2ncq2qk) — Cardiff London OR, United Kingdom
- [Chief of Staff, Group CFO](https://feeny.ai/job/chief-of-staff-group-cfo-referrals-only-london-fg8xem42f7fh) — London, United Kingdom
- [Senior Product Manager - Growth](https://feeny.ai/job/senior-product-manager-growth-referrals-only-london-x8w3pax4qj7r) — London, United Kingdom
- [Director of Product Design](https://feeny.ai/job/director-of-product-design-referrals-only-cardiff-london-or-8ca0hy3vyc09) — Cardiff London OR, United Kingdom
- [Staff Backend Engineer](https://feeny.ai/job/staff-backend-engineer-referrals-only-cardiff-london-or-6w1n8z0gktm9) — Cardiff London OR, United Kingdom
- [Senior Backend Engineer](https://feeny.ai/job/senior-backend-engineer-referrals-only-cardiff-london-or-0weyav3xnjw9) — Cardiff London OR, United Kingdom
- [Android Engineer](https://feeny.ai/job/android-engineer-referrals-only-cardiff-london-or-zgy3wbdg3pyh) — Cardiff London OR, United Kingdom
- [Special Projects Lead](https://feeny.ai/job/special-projects-lead-referrals-only-london-fy6jfn5pkbb1) — London, United Kingdom