19 of 19 Permanent Legacy Code Jobs in London

to attract the best talent on the market. Having received huge investment, they are on a journey to truly disrupt the industry and are not held back by any legacy code or old customers. This means that they're able to build out state-of-the-art, Greenfield code which can focus on being the worlds most More ❯

lightly-coupled service architectures Expectations: Building systems with a constant focus on testing, reliability, scalability, and maintainability. Designing, modeling, and programming in a variety languages and technologies. Working on legacy code as well as green field development. Initiative driving projects to completion. Learning and promoting new technologies with a focus on best practices. Providing on-call support as More ❯

to ensure quality is baked in from the start, while championing best practices and modern QA approaches. We're a fast-moving TransitTech business with plenty of exciting challenges-legacy code, evolving architecture, and new features that need rigorous testing across web, iOS, and Android platforms. If you thrive in an environment where you can make a real More ❯

to ensure quality is baked in from the start, while championing best practices and modern QA approaches. We're a fast-moving TransitTech business with plenty of exciting challenges-legacy code, evolving architecture, and new features that need rigorous testing across web, iOS, and Android platforms. If you thrive in an environment where you can make a real More ❯

initiatives and tech debt. Prepare documentation on the status, operation, and maintenance of software. Clearly and regularly communicate with technical support colleagues and management. Development scheduling and deployment of code sets. Participate in peer-reviews of solution designs and code reviews. Work closely with all stakeholders to troubleshoot product and systems issues, exploring solutions and implementing long-term … fixes to prevent recurrences. Skills, Knowledge & Expertise We have a Microsoft stack, so C#/.NET, Angular and Azure experience is our highest priority from a technical perspective. Legacy code or experience working with large, complex codebases is preferred. ASP.NET/.NET CORE MVC, WPF. Experience of web-related technologies (HTML, XML, CSS, JSON, JavaScript, jQuery). MS More ❯

cashless payments. They're now hiring for a PHP Back-End Developer to join their remote-first team and contribute to a completely modernised Laravel-based platform with no legacy code. This is a great opportunity to work with cutting-edge tools, take ownership of clean, scalable features, and be supported in your professional growth with a tailored development … plan. Key Responsibilities: Write clean, reusable, test-driven code in PHP using Laravel (TDD, OOP best practices). Build and extend APIs, platform features, and 3rd-party integrations (e.g. payment gateways, marketing tools). Maintain platform performance and functionality through robust troubleshooting and optimisation. Collaborate with front-end, mobile, and back-end teams through daily stand-ups and monthly More ❯

for the bank. We are seeking a highly experienced Senior Java Lead Developer to modernize our core financial accounting systems. You will play a critical role in rewriting our legacy sub-ledger application to a modern Java-based architecture. This involves analyzing existing code, designing equivalent Java components, and ensuring a seamless transition while maintaining system functionality and … design, coding, testing, debugging, and implementation Analyze existing modules and shell scripts to design equivalent Java components Develop and implement high-performance, scalable, and secure Java applications to replace legacy code Write clean, well-documented, and testable Java code Collaborate with architects and other developers to define the migration strategy and ensure a smooth transition Work with … relational databases, primarily Sybase ASE and MS SQL, to adapt existing database schemas and queries to the new Java architecture Thoroughly test and validate the migrated Java code to ensure functional equivalence with the legacy system Troubleshoot and resolve technical issues during the migration process Participate in code reviews and contribute to improving development processes Allocate work More ❯

proactive and experienced Senior Android Developer to work across a portfolio of successful apps in a fun, talented team. The apps are fully native, primarily developed in Kotlin, with legacy Java code being phased out. The technologies run directly on the phone with limited server interactions. As a key member of the team, youll have a strong track … best practices. It is envisaged the role will evolve into a leadership position. Responsibilities: Build on exciting new technologies and integration with wearable devices Develop new features, improve existing code work on ambitious projects ranging from low-level algorithms to high-level system design; plus the occasional development of a prototype app Utilise the latest Android SDKs and frameworks … to implement scalable, maintainable and testable architectures Conduct code reviews and champion high-quality code by leveraging unit tests, continuous integration, and code quality tools Essential Skills and experience: 5+ years of high-level Android development experience, with a wider software engineering background (8+ years in total) Excellent Kotlin skills and comfortable with other languages e.g. Java More ❯

proactive and experienced Senior Android Developer to work across a portfolio of successful apps in a fun, talented team. The apps are fully native, primarily developed in Kotlin, with legacy Java code being phased out. The technologies run directly on the phone with limited server interactions. As a key member of the team, you’ll have a strong … best practices. It is envisaged the role will evolve into a leadership position. Responsibilities: Build on exciting new technologies and integration with wearable devices Develop new features, improve existing code - work on ambitious projects ranging from low-level algorithms to high-level system design; plus the occasional development of a prototype app Utilise the latest Android SDKs and frameworks … to implement scalable, maintainable and testable architectures Conduct code reviews and champion high-quality code by leveraging unit tests, continuous integration, and code quality tools Essential Skills and experience: 5+ years of high-level Android development experience, with a wider software engineering background (8+ years in total) Excellent Kotlin skills and comfortable with other languages e.g. Java More ❯

a focus on long-term stability and performance. Collaborate with cross-functional teams, including PO, PDEF, QA, DevOps, and product stakeholders, to define, design, and deliver new features. Refactor legacy code and participate in technical debt reduction. Write clean, scalable, and maintainable code with proper documentation. Participate in code reviews and mentor junior developers where applicable. More ❯

software systems supporting 24/7 global trading. Design and implement full-stack systems Predominately work across Java. Conduct comprehensive testing at unit, functional, and integration levels. Tackle both legacy code enhancements and greenfield development. Qualifications: Proven experience designing, developing, and maintaining mission-critical, high-performance applications. 5+ years of professional experience with Java Knowledge of network communication More ❯

of a cross-functional, agile team, you will shape the frontend roadmap, champion best practices, and foster a culture of engineering excellence. You'll lead the migration from a legacy monolith to a modern microfrontend and Backend-for-Frontend (BFF) ecosystem, leveraging React, Next.js, TypeScript, and advanced communication protocols such as GraphQL and gRPC. What You'll Own Lead … Backend teams to translate complex requirements into elegant, user-centric digital experiences. Advocate for CI/CD best practices, ensuring rapid and safe delivery of features with automated testing, code reviews, and observability. Influence technical strategy, tooling, and processes to continually raise the engineering bar and accelerate delivery velocity. Lead efforts in evaluating and integrating AI tools and automation … innovation. About You Extensive commercial experience building complex frontend applications with React and Next.js, with strong proficiency in TypeScript. Proven track record of architecting scalable frontend systems and migrating legacy codebases to modern frameworks. Deep understanding of accessibility standards (WCAG) and a passion for building inclusive user experiences. Experience working with GraphQL and gRPC APIs in production environments. Exceptional More ❯

function. Role & Responsibilities: Support the redesign of their data stack, including containerising workflows, migrating to cloud SQL, and introducing tools like Prefect. Maintain and optimise 60 Python pipelines, refactoring legacy code into modular components. Keep Power BI dashboards accurate and up to date, supporting evolving business needs. Help implement validation and anomaly detection within their pipelines to ensure … data integrity. Manage Git workflows and assist in setting up lightweight deployment pipelines. Maintain clear, up-to-date records of code, processes, and workflows. Occasionally assist the research desk with Python-based analysis and data visualisation. BSc in Computer Science or a related discipline Good working knowledge of SQL Comfortable using Git for version control Exposure to workflow orchestration More ❯

function. Role & Responsibilities: Support the redesign of their data stack, including containerising workflows, migrating to cloud SQL, and introducing tools like Prefect. Maintain and optimise ~60 Python pipelines, refactoring legacy code into modular components. Keep Power BI dashboards accurate and up to date, supporting evolving business needs. Help implement validation and anomaly detection within their pipelines to ensure … data integrity. Manage Git workflows and assist in setting up lightweight deployment pipelines. Maintain clear, up-to-date records of code, processes, and workflows. Occasionally assist the research desk with Python-based analysis and data visualisation. Skills & Experience: Essentials: BSc in Computer Science or a related discipline Solid Python programming skills Good working knowledge of SQL Comfortable using Git More ❯

end autonomous driving: ranging from initial data strategy, design, development, experimentation, evaluation, and deployment; Able to navigate ambiguities and address uncertainties arising from complex projects involving multiple teams and legacy codebases; Writes high-quality code while being rigorous with Machine Learning experimentation; Collaborate closely with stakeholders from multiple teams in different time zones to define interfaces and requirements More ❯

end autonomous driving: ranging from initial data strategy, design, development, experimentation, evaluation, and deployment; Able to navigate ambiguities and address uncertainties arising from complex projects involving multiple teams and legacy codebases; Writes high-quality code while being rigorous with Machine Learning experimentation; Collaborate closely with stakeholders from multiple teams in different time zones to define interfaces and requirements More ❯

live PnL attribution and feedback to researchers & traders. Hire and mentor the team that will scale this from “clever prototype” to “firm‐wide PnL driver”. Green‐field. No legacy code. You set the standards. The Opportunity All the levers, none of the red tape – direct line to the head of the HFT business, a chance to own the More ❯

live PnL attribution and feedback to researchers & traders. Hire and mentor the team that will scale this from “clever prototype” to “firm‐wide PnL driver”. Green‐field. No legacy code. You set the standards. The Opportunity All the levers, none of the red tape – direct line to the head of the HFT business, a chance to own the More ❯

Responsibilities: Lead technical design for the platform Line manage a team of 3 developers Balance 60/40 split between hands-on coding and managerial duties Oversee modernization of legacy code to .NET 9 Support ISO27001 implementation Experience: Extensive experience with .NET & C# Strong understanding of Azure services Experience implementing ISO27001 Salary: Up to £90,000 Location: London More ❯