Software Engineer (FinTech)

G MASS; Greater London; On-site; GBP 80,000 - 100,000; Full time

Job summary

A global FinTech organization is seeking a Senior Software Engineer in Greater London. You will design and maintain scalable software within a collaborative, Agile team focusing on clean architecture and modern Java development. Ideal candidates will have commercial experience with distributed systems, and strong SQL proficiency, along with familiarity with cloud services. This role offers the chance to mentor junior engineers and make significant architectural contributions. Salary to be discussed and initial 6-month contract with potential for extension.

Qualifications

• Strong commercial experience in software engineering with expertise in modern Java.
• Experience in building enterprise-grade distributed systems.
• Hands-on experience with PostgreSQL, HBase, or Trino.

Responsibilities

• Design, develop and maintain scalable software components.
• Translate business requirements into robust solutions.
• Participate in Agile ceremonies and mentor junior engineers.

Skills

Java expertise

Software engineering practices

SQL proficiency

Distributed systems development

Tools

PostgreSQL

HBase

Trino

gRPC

Job description

G MASS is supporting a global FinTech organisation with the expansion of a core engineering team building enterprise-scale, AI-enabled data products. This role sits within a highly collaborative, Agile engineering environment focused on delivering scalable, cloud-native platforms used across the business.

You’ll work as part of a senior engineering group responsible for designing, building and maintaining high-performance software components within a distributed data ecosystem. The focus is on clean architecture, modern Java development and strong engineering practices.

Key responsibilities

• Design, develop and maintain scalable software and data-modelling components within a distributed platform
• Translate business and technical requirements into robust, well-designed solutions
• Apply best-practice software engineering standards including code reviews, TDD and CI/CD
• Troubleshoot and resolve complex software defects and performance issues
• Actively participate in Agile ceremonies including sprint planning, stand-ups, demos and retrospectives
• Mentor junior engineers through code reviews, pairing and knowledge sharing
• Contribute to architectural decisions to ensure scalability, reliability and security
• Produce and maintain clear technical documentation covering designs and workflows
• Engage with stakeholders to communicate progress, risks and solutions
• Continuously evaluate new tools, frameworks and approaches to improve engineering quality

Qualifications

• Strong commercial experience in software engineering, with deep expertise in Java (modern versions preferred)
• Experience building distributed, enterprise-grade systems
• Proficiency in SQL and experience working with relational and big-data technologies
• Hands-on experience with commonly used databases such as PostgreSQL, HBase or Trino
• Knowledge of gRPC patterns (unary, streaming and REST mapping)
• Solid understanding of OOP design patterns, TDD and enterprise system design
• Comfortable working in Linux environments using command-line tools
• Experience with version control and collaborative development workflows

Nice to have

• Experience with modern Java UI frameworks
• Exposure to Apache Spark, Kafka or Avro
• Cloud experience across AWS, Azure, GCP or Oracle Cloud
• Knowledge of Kubernetes and containerised environments
• Familiarity with DevOps practices and automation
• Experience with additional languages or runtimes (e.g. C#, .NET, Python, JavaScript, GraalVM)

Initial 6-month contract, with strong possibility of extension and/or permanency.

Salary to be discussed.