21 of 21 Legacy Code Jobs in London

kotlin developer for trading platforms

Location
Greater London, England, United Kingdom
outcomes. Задачи: Re-engineer core trading and post-trade systems into event-driven, cloud-native services on the JVM using Java and Kotlin; Modernize legacy components while maintaining the stability of a live, financially significant platform; Build new data and market-expansion platforms, alongside plumbing for cross-margining … stakeholders and upstream and downstream teams to build domain knowledge without relying on Business Analysts; Use AI-assisted and agentic development tools to accelerate legacy code analysis, test generation, prototyping, and refactoring. Требования: Expert-level Java expertise and production Kotlin experience, or a clear appetite to adopt Kotlin ...

Senior Fullstack Software Engineer

Location
Greater London, England, United Kingdom
operations – a mature, revenue-generating system that has evolved over years and continues to scale. If you enjoy owning real systems, thinking architecturally, improving legacy code thoughtfully rather than rewriting it, and being trusted to deliver without heavy supervision, this role will feel unusually well-matched. The role … calm, root‐cause mindset Incrementally improving system architecture using sound design principles (including modular design, DDD‐style thinking, and pragmatic architectural patterns) Reviewing code, raising standards constructively, and contributing to a disciplined engineering culture Leveraging modern tooling (including AI‐assisted development) to improve quality and velocity This ...

Senior Software Engineer

Location
City Of London, England, United Kingdom
untangling complex systems and modernising core infrastructure without breaking production. This is an exciting opportunity to modernise core C#/SQL systems! Extract legacy business logic, build clean services, and verify changes in shadow mode with zero downtime to revenue flows. Extract business rules scattered across C#, embedded JavaScript … rules assemblies. Build new services cleanly. with proper Dependency Injection (DI), robust authentication/authorization, structured logging, and full observability. Work fluently across both legacy .NET Framework 4.8 (ASP.NET MVC5, WebAPI 2, EF6) and modern .NET, as both will coexist for the whole transition period. Navigate across the multiple ...

Android Engineer

Hiring Organisation
ASOS
Location
London, UK
Employment Type
Full-time
Developer KeynotesKotlin & Jetpack Compose first approachOver 10M+ downloadsThe codebase uses modern Android Jetpack components, Kotlin Coroutines, Flow/StateFlow, and RxJava in legacy areasMake an impact on millions of customersNever ending chance of experimenting with latest tech, including KMM, Jetpack Compose and more! We have done some significant work … Android developerYou are extremely comfortable with KotlinYou know reactive programming techniquesYou can contribute to discussions on technical architecture and design You believe that all code is legacy code if it isn't unit/UI testedYou love agile/scrum and can work as part ...

AI-Native Software Engineer

Location
Greater London, England, United Kingdom
codebase gets easier for both humans and AI tooling to work in. Improve how the codebase is documented and structured so AI code assistants can be guided effectively, for example context files, architecture notes and structured inline documentation. Convert product specifications into precise engineering specifications, building in enough specificity … context that a code assistant can deliver efficiently and reliably, with minimal iteration, rather than being nudged repeatedly toward a solution. Use proofs of concept to prove out the right level of specification and methodology, so AI-assisted changes land reliably and with confidence. Deliver across a full SDLC ...

.Net Developer

Location
Greater London, England, United Kingdom
development team to maintain and update the bespoke ecommerce platform, taking a proactive approach in evolving the back-end technology stack and migrating legacy code across to an ASP.NET framework. Advocate integration of technologies and development methodologies to help drive the business forward and ensure a robust, scalable … Manager to maintain and update the bespoke Classic ASP ecommerce platform. Develop new features for a localized ASP.NET MVC 5 platform and contribute migrating legacy features over to this new platform. Write maintainable, scalable, fault-tolerant code, utilizing SOLID principles and OO design/architectural patterns, TDD, etc. ...

VP, Product & Engineering Coda & FP&A

Hiring Organisation
Unit4
Location
Greater London, United Kingdom
Employment Type
Full Time
slowing the pace of new development. Demonstrable hands-on experience applying AI to software engineering at team scale with measurable results (e.g. AI-driven code modernisation, test generation for legacy code or agentic development workflows) and an informed point of view on how AI will change both ...

VP, Product & Engineering Coda & FP&A

Location
Greater London, England, United Kingdom
slowing the pace of new development. Demonstrable hands-on experience applying AI to software engineering at team scale with measurable results (e.g. AI-driven code modernisation, test generation for legacy code or agentic development workflows) and an informed point of view on how AI will change both ...

Staff Engineer, Test Integration, Modelling and Simulation (R5601)

Location
Greater London, England, United Kingdom
Extensive experience in C++ using modern C++ (C++17/20) while possessing a solid understanding of older standards (C++98/03) for adapting to legacy code and systems seamlessly. Experience in Python. Programming experience in a Linux environment (Windows experience is a bonus). Expertise with Docker ...

Senior Front Office Developer - HFT

Hiring Organisation
Quant Capital
Location
London, UK
Employment Type
Full-time
Java, to successfully accomplish development tasks. Conduct thorough testing at the unit, functional, and integration levels to ensure software reliability and performance. Handle both legacy code and new development projects. Promote collaboration and synergy among traders, researchers, and software engineers. Qualifications: Experience in designing, developing, and supporting mission ...

Android Engineer - Inside Ir35

Hiring Organisation
Salt
Location
London, United Kingdom
Employment Type
Contract
Contract Rate
GBP Daily
Product, Design, QA and Engineering teams * Troubleshoot, debug and resolve technical issues * Contribute to performance optimisation and improving application quality * Work with existing and Legacy codebases where required * Write unit and integration tests * Design solutions to open-ended technical problems * Work effectively within a globally distributed engineering environment …/or CircleCI * CI/CD practices * JUnit and Espresso * Unit and integration testing * Experience debugging and optimising mobile applications * Comfortable working with Legacy code * Strong communication and collaboration skills Technologies Kotlin | Coroutines | Flow | Jetpack Compose | MVI | REST APIs | OkHttp | Dagger | Gradle | GitHub Actions | CircleCI | Espresso | JUnit | WireMock ...

Senior Software Development Engineer

Location
Greater London, England, United Kingdom
Hands on experience with Kotlin for server side, or/and React and Typescript for the frontend. Proven track record of refactoring and modernising legacy codebases and architectures, improving performance and maintainability while minimising risk and customer impact. Track record of integrating and optimizing AI/ML-enabled features ...

Senior Software Engineer, Quant trading - Python, RUST, C++

Hiring Organisation
Quant Capital
Location
London, UK
Employment Type
Full-time
Java, to successfully accomplish development tasks. Conduct thorough testing at the unit, functional, and integration levels to ensure software reliability and performance. Handle both legacy code and new development projects. Promote collaboration and synergy among traders, researchers, and software engineers. Qualifications: Experience in designing, developing, and supporting mission ...

Senior Software Engineer, Quant trading

Hiring Organisation
Quant Capital
Location
London, UK
Employment Type
Full-time
Java, to successfully accomplish development tasks. Conduct thorough testing at the unit, functional, and integration levels to ensure software reliability and performance. Handle both legacy code and new development projects. Promote collaboration and synergy among traders, researchers, and software engineers. Qualifications: Experience in designing, developing, and supporting mission ...

Senior Software Engineer, Quant trading - Python, Java, C++

Hiring Organisation
Quant Capital
Location
London, UK
Employment Type
Full-time
Java, to successfully accomplish development tasks. Conduct thorough testing at the unit, functional, and integration levels to ensure software reliability and performance. Handle both legacy code and new development projects. Promote collaboration and synergy among traders, researchers, and software engineers. Qualifications: Experience in designing, developing, and supporting mission ...

Global Banking & Markets - Software Engineer - Vice President - London London · United Kingdom [...]

Location
Greater London, England, United Kingdom
lean heavily into AI‐driven development. Using Goldman Sachs' AI tooling and agentic coding assistants, you will govern multiple AI agents, rapidly comprehend large legacy codebases, generate and assess production‐quality code, and accelerate every phase of the software development lifecycle. Your Impact Drive a strategic transformation : Work … centric, AI‐driven world, and define and deliver the requirements for CTL integration. Multiply your output with AI : Orchestrate AI coding agents (e.g., Claude Code, GitHub Copilot, Devin, Gemini Code Assist) across all stages of the SDLC while maintaining mastery, quality, and production fitness over all AI‐generated ...

Global Banking & Markets - Software Engineer - Vice President - London

Hiring Organisation
Goldman Sachs
Location
London, UK
Employment Type
Full-time
lean heavily into AI-driven development. Using Goldman Sachs' AI tooling and agentic coding assistants, you will govern multiple AI agents, rapidly comprehend large legacy codebases, generate and assess production-quality code, and accelerate every phase of the software development lifecycle. Your ImpactDrive a strategic transformation: Work alongside … centric, AI-driven world, and define and deliver the requirements for CTL integration. Multiply your output with AI: Orchestrate AI coding agents (e.g., Claude Code, GitHub Copilot, Devin, Gemini Code Assist) across all stages of the SDLC while maintaining mastery, quality, and production fitness over all AI-generated ...

Global Banking & Markets - Software Engineer - Associate - London

Location
City Of London, England, United Kingdom
willlean heavily into AI-driven development. Using Goldman Sachs' AI tooling and agentic coding assistants, you will govern multiple AI agents, rapidly comprehend large legacy codebases, generate and assess production-quality code, and accelerate every phase of the software development lifecycle. Your Impact Drive a strategic transformation : Work … centric, AI-driven world, and define and deliver the requirements for CTL integration. Multiply your output with AI : Orchestrate AI coding agents (e.g., Claude Code, GitHub Copilot, Devin, Gemini Code Assist) across all stages of the SDLC while maintaining mastery, quality, and production fitness over all AI-generated ...

Frontend Engineer II (React/TypeScript) – Hybrid London

Location
Greater London, England, United Kingdom
team in London. You will build high-quality front-end features with React and TypeScript, focusing on clarity, performance, and maintainability. You will refactor legacy code, fix issues across the stack, collaborate with product managers and designers, and provide code reviews while mentoring teammates to improve quality ...

Senior Fullstack Engineer — Platform Architect

Location
Greater London, England, United Kingdom
high-quality engineering on mature platforms. The ideal candidate will have 8-15 years of experience, strong Python skills, and comfort navigating complex legacy code. This position offers an opportunity to make architectural decisions and contribute to the company's operational growth, while working alongside senior decision-makers. #J ...

Senior iOS Engineer — Scale Apps, Swift & AI in Dev

Location
Greater London, England, United Kingdom
serving millions with events, news and app experiences. We seek an experienced iOS engineer to design major features, align iOS/Android APIs, modernise legacy code, and raise release quality through tests and monitoring. You will mentor teammates, collaborate with web/platform teams, and help steer ...