Senior / Principal Kotlin Engineer
You will work primarily with Kotlin and modern engineering practices including TDD, clean code, and SOLID principles. You'll join small teams on greenfield rebuilds for leading financial institutions, replacing legacy systems with cloud-aligned solutions using Kotlin.
Free Tailor for ATS: 10/10 runs left
We are looking for several Kotlin developers, from experienced seniors to hands-on principal engineers, to join long-term greenfield projects with leading financial institutions in London.
You will be part of small, high-calibre engineering teams delivering strategic rebuilds and modernisation projects, replacing legacy systems with clean, cloud-aligned solutions built on Kotlin and modern engineering practices. These are not maintenance roles - they are about writing great code, solving challenging problems, and shaping architecture from the ground up.
You will be joining teams working on genuinely greenfield, strategic rebuilds with clear scope, autonomy, and modern tech stacks. There is little to no BAU work, and plenty of room to shape architecture, influence direction, and own your contributions end-to-end.
This is a great opportunity to deepen your Kotlin expertise, work alongside highly capable engineers, and gain exposure to large-scale systems and distributed architectures within major financial organisations with no prior banking experience required.
This is a collaborative, trust-based environment where developers have real autonomy, clear ownership, and meaningful technical input. There is a genuinely friendly culture in the team - people take pride in their craft and support each other to deliver excellent software.
Core Skills
Strong Kotlin skills, with depth in modern engineering practices (TDD, clean code, SOLID principles)
Demonstrated knowledge and hands-on experience in designing scalable, mission-critical systems
Strong understanding of system integration and end-to-end test design principles
Ability to work effectively in a collaborative, high-autonomy environment
Experience with greenfield builds and/or incremental legacy replacement
Strong problem-solving ability and architectural reasoning
Hands-on mindset 6 this is a coding role first and foremost
Nice To Have
Experience with large-scale data processing or distributed query systems (e.g. Spark, Beam, Flink, Trino, Presto, Hive, etc.), or the ability to quickly pick up similar tools
Exposure to financial services or enterprise-scale systems
Company Benefits
Private Pension
Private healthcare
Hybrid working
25 days holiday
Interview Process
1 - Interview with one of the Talent Acquisition Team
2 - All in One interview (tech test and Q+A) with a current JUXT employee
3 - Interview with the client (technical)