1 to 25 of 29 Legacy Code Jobs in London

Lead Application Architect

Location
Greater London, England, United Kingdom
designs, and the development team, who deliver them. You will turn HLDs into well‐documented, implementable designs (Low-Level Design) and make sure the code that results is consistent, secure and maintainable. About Bestway Bestway Group is a diversified multinational family owned business with annualised turnover in excess … communities through its operations across the UK, Pakistan and the Middle East Responsibilities Application & low-level design: Own component-level (C4 Level 3) and code-level (C4 Level 4) design and LLDs for our applications. Translate Solution Architects’ HLDs into clear implementation designs, and make sure the team understands ...

Lead Application Architect

Hiring Organisation
BESTWAY WHOLESALE LIMITED
Location
North West London, London, United Kingdom
Employment Type
Permanent
designs, and the development team, who deliver them. You will turn HLDs into well-documented, implementable designs (Low-Level Design) and make sure the code that results is consistent, secure and maintainable. About Bestway Bestway Group is a diversified multinational family owned business with annualised turnover in excess … communities through its operations across the UK, Pakistan and the Middle East Responsibilities: Application & low-level design: Own component-level (C4 Level 3) and code-level (C4 Level 4) design and LLDs for our applications. Translate Solution Architects HLDs into clear implementation designs, and make sure the team understands ...

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 ...

iOS Engineer (Contractor)

Hiring Organisation
EPAM Systems Ltd
Location
London, United Kingdom
Employment Type
Contract
Contract Rate
GBP Annual
Mobile applications that serve tens of millions of cardholders worldwide demand a relentless focus on user experience and code quality. As an iOS Engineer, working in a hybrid mode in London, you will sit at the intersection of scale and creativity, where ambiguity is part of the challenge … work matters because every feature you help shape reaches users around the world. Responsibilities Build and maintain iOS applications and write and delete code as needed Use build tools such as Tuist, xcodebuild, GitHub Actions and Circle CI and apply continuous integration patterns Find and fix bugs and apply ...

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 ...

Senior Software Engineer (.NET/C#)

Location
Greater London, England, United Kingdom
stack features across .NET 8 services and React front ends Lead large projects from design to rollout with one or two other engineers Modernise legacy code, building in automated tests and observability Partner with product, engineering and client support, and join our on-call rotation Mentor engineers through … code review and pairing, and help us hire WHAT YOU'LL BRING: 4–8 years of professional software development experience Strong C#/.NET backend skills, including in large, established codebases Experience with React, TypeScript and SQL Daily, hands-on use of AI coding assistants A record of delivering ...

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 ...

Platform Engineer (Kubernetes on-premises)

Location
Greater London, England, United Kingdom
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. … 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 Maven ...

FPGA Engineer / Senior FPGA Engineer - Power Supplies

Hiring Organisation
DIAMOND LIGHT SOURCE LIMITED
Location
London, England, United Kingdom
FPGA Engineer or Senor FPGA Engineer level, depending on the strength of your skills, experience and qualifications. Key Responsibilities: Develop, maintain, and debug HDL code for Xilinx FPGAs in Vivado, implementing full-cycle firmware for Diamond magnet power supplies, including feedback control, filtering, and interlock handling using state machines. … with hardware engineers and the Control Group to optimise performance, resolve issues, and develop reliable Ethernet-based control interfaces. Review, refactor, and document HDL code in line with Diamond standards, ensuring proper version control and maintainability. Contribute to electronic circuit design, simulation (SPICE, MATLAB), PCB design, and prototype testing ...

Senior Software Engineer, Unified Platform - Trade Management and Trade & Order Processing

Location
Greater London, England, United Kingdom
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. ...

Senior Software Development Engineer

Hiring Organisation
Expedia
Location
London, UK
Employment Type
Full-time
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 ...

Staff Product Engineer

Hiring Organisation
Consortia
Location
London, England, United Kingdom
product outcomes, designing, building and scaling services from first principles with the autonomy to make technical decisions stick.With a low-meeting culture, zero legacy code and colleagues who are all staff-level engineers with 7+ years’ experience, this is a place for experienced engineers who want to think … secure, performant and scalable services in PHP (Laravel/Symfony) and JavaScript, treating non-functional requirements as first-class problems. Write clean, well-tested code using patterns like DDD and CQRS, keeping the codebase modern through proactive refactoring and avoiding unnecessary technical debt. Collaborate with DevOps engineers to ensure ...

Unified Platform - Business Experience - Software Engineer

Location
Greater London, England, United Kingdom
medium-sized applications that business people use in their day-to-day work. What you will do in this role Primarily work on legacy code, and sometimes work on green-field development. Lead small projects to completion. Hands on with business users, sometimes collaborating with them to improve … Strong verbal and written communication skills. Fluency in one or both of Python and C#. Ability to work with AI coding assistants (e.g. Claude Code) to accelerate software development. Bachelor's degree in Computer Science or Software Engineering (or equivalent). 6+ years of Software Engineering experience. For more ...

Unified Platform - Business Experience - Software Engineer

Hiring Organisation
DRW
Location
London, UK
Employment Type
Full-time
small- to medium-sized applications that business people use in their day-to-day work. What you will do in this rolePrimarily work on legacy code, and sometimes work on green-field development. Lead small projects to completion. Hands on with business users, sometimes collaborating with them … solutions. Strong verbal and written communication skills. Fluency in one or both of Python and C#.Ability to work with AI coding assistants (e.g. Claude Code) to accelerate software development. Bachelor's degree in Computer Science or Software Engineering (or equivalent).6+ years of Software Engineering experience. For more information ...

Senior Android Engineer

Location
Greater London, England, United Kingdom
encouraged to help others grow – you will pass on your expertise to other developers, whilst continuing to grow yourself Sometimes deciding what code to write is as hard as writing the code itself. As an engineer you'll be involved in product decisions as well as technical ones. … more of modern Android development tools, including Jetpack Compose, Coroutines/Flow, MVVM, Webviews, other Jetpack libraries, and modular app architectures. You test your code and promote a culture of testing. Demonstrate experience with some of JVM unit testing, instrumented testing, and UI regression testing You are comfortable working ...

Software Engineer - Business Experience Platform (Python/C#)

Location
Greater London, England, United Kingdom
London is seeking a Software Engineer for the Unified Platform - Business Experience team. You will maintain legacy code and contribute to green-field development to empower business users with DRW technology. The role requires 6+ years of software engineering, fluency in Python and/or C# ...

Senior Software Engineer – Payments Platform (C#/.NET)

Location
Greater London, England, United Kingdom
join the Treasury Payments team. You will design and deliver full-stack features across .NET 8 services and React front ends, modernising a large legacy codebase with automated tests and observability. Daily collaboration with product, engineering and client support is expected, including on-call rotation. You will own critical ...

FX Risk Lead Java Developer + AI (VP)

Location
Greater London, England, United Kingdom
work today. You’ll have hands‐on access to Citi’s internal GenAI ecosystem: from GitHub Copilot and Devin.AI for agentic code generation, to Citi Squad for automated code reviews, to Stylus Workspaces — Citi’s in‐house GenAI platform powered by top‐tier LLMs including Gemini, OpenAI, Claude … decisions — from system design and architectural choices to setting engineering standards across the team Translate complex business requirements into robust, high‐quality code — working closely with quantitative analysts, traders, and business stakeholders Craft high‐quality, scalable software in an agile environment, leveraging AI‐powered coding tools to accelerate delivery ...

Senior .NET Engineer – On-site in Central London

Location
Greater London, England, United Kingdom
solutions. You will work with cross-functional teams to translate user needs into robust backend services. The role focuses on API development, modernization of legacy code, and strong database design with SQL. UK-based applicants with full right to work are required. #J-18808-Ljbffr ...

Business Experience Software Engineer | Python/C#

Location
Greater London, England, United Kingdom
seeking a Software Engineer for the Unified Platform - Business Experience team in London. You will contribute to legacy code, take ownership of small projects and collaborate with business users to improve tooling. Fluency in Python or C#, strong communication, and 6+ years in software engineering are required; Bachelor ...

Impactful iOS Engineer – Hybrid (London)

Location
Greater London, England, United Kingdom
globally distributed team. You should have a degree or equivalent experience, solid UIKit/MVVM knowledge, REST APIs, and familiarity with Objective-C legacy code. Join a fast-paced, small-team setting with global impact. #J-18808-Ljbffr ...

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 PHP Backend Architect & Tech Lead - Fintech

Location
Greater London, England, United Kingdom
architecture decisions, and mentor engineers across product teams. You will optimize databases, APIs, and processing workflows, participate in incident response, and drive modernisation of legacy code without business disruption. Strong knowledge of PHP 8+, Yii2, PostgreSQL and CI/CD required. #J-18808-Ljbffr ...

Senior Unity Developer (6 months FTC) ITV Careers

Location
Greater London, England, United Kingdom
role We are looking for a senior unity developer to join our ranks at Metavision Studios to develop, and maintain live-ops of our legacy projects. In doing so, you’d play a core part in our mission to expand and build on the success … Interactive Media portfolio. This is a high impact role, where you’d be accountable for how Metavision Studios steps into the more legacy mobile & console spaces. Sat within our wider UGC team at Metavision, you’d be part of the foundation of mobile expansion working with our Studio ...