26 to 50 of 85 Legacy Code Jobs in London

developer environment. Work closely with cross-functional teams to ensure effective delivery and knowledge sharing across the organisation. Support the growth of junior developers through guidance and mentorship. Perform code reviews to uphold high standards of code quality and reinforce best practices. Key Experience Required: Extensive hands-on experience with C++, including deep familiarity with commercial development environments. … continuous professional growth. Exposure to high-level languages; Python and C# experience is a plus. Familiarity with CI/CD workflows and tooling. Skilled in working with and modernizing legacy codebases. The Package: Basic annual salary up to £85,000 (dependant on experience) Occasional expensed travel for office and home working expenses. Cycle to work scheme. 25 days of More ❯

and support full stack software systems in multiple languages (Python, Java, Rust, Typescript). Collaborate widely with trading desks and supporting DRW business units. Work with both greenfield and legacy code, as well as assist trading desks with taking proof of concept ideas to production. Provide on-call support as needed. Qualifications: Have a minimum of 2+ years More ❯

options trading desks, designing and supporting full-stack systems in multiple languages (Python, Java, Rust, Typescript) Collaborating with trading desks and supporting business units Working with both greenfield and legacy code, assisting in taking proof of concept ideas to production Providing on-call support as needed Qualifications: Minimum of 2+ years' experience with Java or Python, or demonstrated More ❯

long-term development goals. Building systems with a constant focus on testing, reliability, scalability, and maintainability. Designing, modeling, and programming in a variety of 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 ❯

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 ❯

and deliver innovative and impactful solutions to our users. The Opportunity: As a Software Engineer on the Desktop team, this is your opportunity to help bring Rust into our legacy codebase, deliver impactful features, and improve performance for a global user base—all while working alongside a passionate team of experts. This role joins 13 talented front and back … flagship application, cherished by millions of users worldwide. As we work to modernize and enhance the product, this role plays a vital role in implementing new features and transitioning legacy code to Rust and C++. This role requires a solid background in back-end software development and proficiency in both languages. You will work closely within and across … effective work coordination across various virtual communication platforms such as email and video conferencing. What you’ll do: Maintain and improve the back-end codebase of the Thunderbird application. Code feature improvements across major areas, including the calendar and mail components. Implement and refactor mail protocols, converting legacy code to more efficient low-level languages such as More ❯

developer environment. Work closely with cross-functional teams to ensure effective delivery and knowledge sharing across the organisation. Support the growth of junior developers through guidance and mentorship. Perform code reviews to uphold high standards of code quality and reinforce best practices. Key Experience Required: Extensive hands-on experience with C++, including deep familiarity with commercial development environments. … continuous professional growth. Exposure to high-level languages; Python and C# experience is a plus. Familiarity with CI/CD workflows and tooling. Skilled in working with and modernizing legacy codebases. The Package: Basic annual salary up to £85,000 (dependant on experience) Remote working. Occasional expensed travel for office and home working expenses. Cycle to work scheme. Pension More ❯

developer environment. Work closely with cross-functional teams to ensure effective delivery and knowledge sharing across the organisation. Support the growth of junior developers through guidance and mentorship. Perform code reviews to uphold high standards of code quality and reinforce best practices. Key Experience Required: Extensive hands-on experience with C++, including deep familiarity with commercial development environments. … continuous professional growth. Exposure to high-level languages; Python and C# experience is a plus. Familiarity with CI/CD workflows and tooling. Skilled in working with and modernizing legacy codebases. The Package: Basic annual salary up to £85,000 (dependant on experience) Remote working. Occasional expensed travel for office and home working expenses. Cycle to work scheme. Pension More ❯

developer environment. Work closely with cross-functional teams to ensure effective delivery and knowledge sharing across the organisation. Support the growth of junior developers through guidance and mentorship. Perform code reviews to uphold high standards of code quality and reinforce best practices. Key Experience Required: Extensive hands-on experience with C++, including deep familiarity with commercial development environments. … continuous professional growth. Exposure to high-level languages; Python and C# experience is a plus. Familiarity with CI/CD workflows and tooling. Skilled in working with and modernizing legacy codebases. The Package: Basic annual salary up to £85,000 (dependant on experience) Remote working. Occasional expensed travel for office and home working expenses. Cycle to work scheme. Pension More ❯

developer environment. Work closely with cross-functional teams to ensure effective delivery and knowledge sharing across the organisation. Support the growth of junior developers through guidance and mentorship. Perform code reviews to uphold high standards of code quality and reinforce best practices. Key Experience Required: Extensive hands-on experience with C++, including deep familiarity with commercial development environments. … continuous professional growth. Exposure to high-level languages; Python and C# experience is a plus. Familiarity with CI/CD workflows and tooling. Skilled in working with and modernizing legacy codebases. The Package: Basic annual salary up to £85,000 (dependant on experience) Remote working. Occasional expensed travel for office and home working expenses. Cycle to work scheme. Pension 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 ❯

functions within the firm. MUST HAVE Building systems with a constant focus on reliability, scalability, and maintainability. Designing and programming in a variety of 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. Experience building and automating various … home options 1 day a week Highly competitive compensation plus annual discretionary bonus Working with a team of high-performing individuals, we all push each other forward Informal dress code and excellent work/life balance A fast-growing global firm with plenty of opportunities where you will have a significant impact Seniority level Seniority level Associate Employment type More ❯

effectively contribute to cloud-native applications. Proficiency in constructing and managing services, including establishing standard APIs, integrating monitoring and alerting services, and expert integration with external systems. Comfort with legacy code, allowing you to maintain it and propose improvements once familiar with our workflows to help reduce technical debt. A strong commitment to quality, expecting your code More ❯

functions within the firm. MUST HAVE Building systems with a constant focus on reliability, scalability, and maintainability. Designing and programming in a variety of 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. Experience building and automating various … home options 1 day a week Highly competitive compensation plus annual discretionary bonus Working with a team of high-performing individuals, we all push each other forward Informal dress code and excellent work/life balance A fast-growing global firm with plenty of opportunities where you will have a significant impact Apply for this job * indicates a required More ❯

of the energy grid. Design and deliver scalable front-end systems using React, TypeScript, and Next.js Work with large datasets and integrate secure APIs/microservices Modernise and refactor legacy codebases to enterprise standards Collaborate in a DevSecOps environment with strict CI/CD and compliance requirements Experience: Advanced React & TypeScript experience with strong programming fundamentals Skilled in managing More ❯

emphasis on object-oriented programming (OOP) principles to develop, maintain, and innovate scalable data products. Proficient in modern typed Python, committed to unit testing new features, and actively improving legacy codebases. Strong working knowledge of version control systems such as Git to enable collaborative, agile development workflows. Skilled in data validation, analysis, and visualization to interpret simulation results, with More ❯

as fast, hassle free processes to deliver an unbeatable customer experience. The role You love to build new things but also don't shy away from digging into a legacy codebase. You love to work in a complex problem domain that is implemented with simple software systems. You have an interest or experience in Functional Programming, microservices and/ More ❯

our core financial accounting systems. You will play a critical role in migrating existing C++ modules and shell scripts 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 performance. This role is based at our London office, interfacing with global technology and business … teams. Responsibilities: Analyze existing C++ modules and shell scripts and 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 C++ system. Troubleshoot and resolve technical issues during the migration process. Participate in code reviews and contribute to improving development processes. Qualifications: Hands-on experience in Java More ❯

proactive and require minimal supervision or mentoring to complete tasks Review specifications produced by architects and formal methods specialists Contribute to the design of algorithms Write clean, straightforward, efficient code that satisfies previously agreed acceptance criteria and specifications Commit often and submit small pull requests frequently Cover your code with unit, property and integration tests when applicable Review … the pull requests of your team mates Fix bugs in your own code and in legacy code from others Be available for emergency fixing of severity 1 issues on deployed products Integrate software components and third-party libraries Verify and deploy programs and systems Troubleshoot, debug and upgrade existing software Write documentation for the code Write … technical user manuals Be knowledgeable of distributed and concurrent computation Be knowledgeable of the basics of cryptography Write idiomatic code that satisfies the acceptance criteria of a given task Write tests (unit tests, property tests) that provide sufficient and non-superfluous efficient code coverage. Document code and APIs concisely and unambiguously Break down tasks into sub-tasks More ❯

proactive and require minimal supervision or mentoring to complete tasks Review specifications produced by architects and formal methods specialists Contribute to the design of algorithms Write clean, straightforward, efficient code that satisfies previously agreed acceptance criteria and specifications Commit often and submit small pull requests frequently Cover your code with unit, property and integration tests when applicable Review … the pull requests of your team mates Fix bugs in your own code and in legacy code from others Be available for emergency fixing of severity 1 issues on deployed products Integrate software components and third-party libraries Verify and deploy programs and systems Troubleshoot, debug and upgrade existing software Write documentation for the code Write … technical user manuals Be knowledgeable of distributed and concurrent computation Be knowledgeable of the basics of cryptography Write idiomatic code that satisfies the acceptance criteria of a given task Write tests (unit tests, property tests) that provide sufficient and non-superfluous efficient code coverage. Document code and APIs concisely and unambiguously Break down tasks into sub-tasks More ❯

with a flexible schedule. Modern tech stack : TypeScript, Vue.js, React, Node.js, Vite, Docker, CI/CD, and more. Supportive culture : Collaborative, engineering-led environment with a strong focus on code quality and security. Be a founding engineer : We're transitioning from third-party vendors to an in-house teamyoull be one of our first engineering hires. Your Day-to … Day Build full-stack features with Vue.js/React and Node.js Migrate services to Node.js v22 and TypeScript Refactor legacy code to use modern frameworks and tooling (Vite, esbuild) Design and maintain shared component libraries Enhance system performance, test coverage, and reliability Collaborate with DevOps on CI/CD and containerisation Mentor junior engineers and document best practices 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 ❯

closely with both Software and Hardware teams to deliver high-quality, efficient solutions. KEY RESPONSIBILITIES: Design, implement, and optimize the Routing Algorithm (RA) in C, ensuring adherence to existing code standards and minimizing system impact. Collaborate with multidisciplinary teams, including Software and Hardware engineers, to ensure the successful integration of RA within the payload software framework. Analyze and understand … C for developing complex algorithms in real-time systems. Operating Systems: Strong experience with Linux environments. Testing: Hands-on experience with unit testing, design validation, and test execution. Flight Code Development: Familiarity with the unique requirements and constraints of flight software for satellite systems. Design and Implementation: Proven ability to design, implement, and optimize solutions in high-performance environments. … Experience with legacy codebases, with an emphasis on impact analysis and optimization. Strong understanding of software-hardware interactions in embedded systems. Excellent problem-solving skills and a detail-oriented mindset. PREFERRED QUALIFICATIONS: Bachelor’s or Master’s degree in Computer Science, Engineering, or a related field. Familiarity with satellite communication protocols and systems. Experience in Agile development environments. BENEFITS More ❯

and advancement of complex software • Stay abreast of the latest developments in C++ and related technologies, contributing to a progressive developer experience • Mentor and coach junior team members • Conduct code reviews, embedding quality and promoting best practices • Collaborate closely with other teams to ensure smooth delivery and knowledge distribution • Promote a balance between business value, technological improvements, and near … and communication skills • Industry experience with multi-threading and complex memory management • Keen interest in continuous improvement and personal development • Experience with CI/CD pipelines • Adept in managing legacy code bases • Experience with higher level languages - specifically Python and C# would be beneficial • Comfortable working across technology domains and software stacks • Strong knowledge of Linux and Windows More ❯

coupled service architectures. Responsibilities Building systems with a constant focus on testing, reliability, scalability, and maintainability. Designing, modeling, and programming in a variety of 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 ❯