Software Developer (Java)

LMAX Group; City of Westminster; On-site; GBP 80,000 - 100,000; Full time

Job summary

A leading financial technology firm is seeking a Junior Software Developer to join their team in London. You will work in a collaborative office environment, focusing on high-performance Java applications. The ideal candidate is passionate about software development and enjoys pair programming while striving for continuous learning and improvement. The company offers generous benefits, including 25 days of holiday and a wellness programme.

Benefits

25 days of holiday

Bonus

Pension contribution

Private medical, dental, and vision coverage

Life assurance

Critical illness cover

Wellness contribution programme

Learning and development programmes

Electric Vehicle Scheme

Cycle to Work Scheme

Season Ticket Loan

Qualifications

• Write performant, reliable, and well-tested code.
• Collaborate with small teams of developers and testers.

Responsibilities

• Work across the stack to solve a variety of problems.
• Engage in pair programming and knowledge sharing.

Skills

Passion for software development

Ability to work in a dynamic environment

Experience with pair programming

Tools

Core Java

MySQL

Kafka

JavaScript

Vue.js

Kubernetes

Python

JUnit

Job description

Junior Software Developer (Java)

Company: LMAX Group

Location: London, Greater London, United Kingdom

Date Posted: 2025-11-11T08:09:34Z

Valid Through: 2026-02-09T08:09:34Z

Employment Type: FULL_TIME

Salary: N/A-N/A N/A per N/A

Description

LMAX is renowned for its high-performance, ultra-low latency (we measure in microseconds) exchange written in core Java. We constantly push technology further than most, especially in our greenfield projects, driving the financial industry in new directions.

Developers are encouraged to constantly develop and learn new skills. Pair programming supports continual growth of knowledge and sharing of expertise, alongside regular team rotations ensuring everyone gains first‑hand knowledge on all areas of our codebase. Friday afternoons are set aside as personal development time where you can explore a different coding language, research bleeding edge technologies, or play around with one of our environments. There is also regularly scheduled time to improve developer experience and reduce technical debt - directed by developers.

Our continuous integration and testing culture allows us to have confidence in our builds and develop quickly. We have over 30,000 acceptance tests running every 25 mins in our CI, alongside extensive test suites (performance, compatibility, migration, resilience). Continuous Delivery was pioneered at LMAX one of the authors worked here while writing the book). Due to pair programming and testing we don't do pull requests, we push directly to our monorepo with a "revert first, ask questions later" attitude.

If you want to work with great developer practices like fast feedback across all aspects of your work, a cooperative culture, and only shipping things when they're ready, while being at the heart of a thriving exchange with opportunities to learn about the finance industry, then LMAX is for you!

What you should expect

• Collaborative office environment with constant pairing and plenty of social activities
• Work across the stack to solve a problem – you might be working with a performance critical component, integrating a new blockchain, or designing a greenfield cloud‑based system
• Regular opportunities to learn and develop yourself with internal tech talks, ability to travel to conferences, and dedicated time for your personal development

What you’ll be working with

• Backend: Distributed, event‑driven core Java (90% of the code‑base), MySQL, Kafka
• Frontend: JavaScript, Vue.js
• Deployment: Kubernetes, Nomad
• Data analytics: Python & Jupyter notebooks, Parquet, Docker
• Testing: JUnit, JMH, JCStress, Jenkins, Selenium, many in‑house tools…
• OS: Linux (Fedora for development, Rocky in production)

The LMAX way is to use the right tool for the job so this is just a flavour of what you’ll be working with, and isn’t a list of requirements!

Requirements

• Be passionate about software development. Bad code offends you!
• Work in a dynamic environment enabled by fast feedback; the heart of our ethos
• Pair programming in small teams of developers and testers (who also write code)
• Share knowledge and learn from like‑minded peers
• Work across a variety of teams covering a wide range of technologies
• Write performant, reliable, and well‑tested code – shipping only when it’s ready

Benefits

• 25 days of holiday
• Bonus
• Pension contribution
• Private medical, dental, and vision coverage
• Life assurance
• Critical illness cover
• Wellness contribution programme with access to ClassPass
• Plumm Platform
• Five volunteering days
• Give as You Earn initiative
• Learning and development programmes
• Electric Vehicle Scheme
• Cycle to Work Scheme
• Season Ticket Loan