12 senior software engineer jobs found in London

Senior Software Engineer - Outside IR35 - Contract (Energy) About the role We are looking for a Senior Software Engineer (ideally with some Data Engineering experience) to join our client team in the energy trading sector. End date is not certain, but likely to be December 2026 or early Q1 2027. We are looking for experience in the following technologies: Microsoft Azure ecosystem Understanding of networking & security options in Microsoft Azure Infrastructure-as-code (preferably Bicep) Python Experience in the below would also be beneficial: Azure DevOps (pipelines) SQL We generally spend 2 days per week on-site with the client in central London (Monday & Thursday). £500-600 per day outside IR35 Start date: 10/08/2026 End date: December 2026 or early Q1 2027 About Softwire Softwire is a leading UK technology and strategy consultancy. From enterprise to government, we help visionary organisations turn...

Java Developer / Software Engineer - Design & Build Fintech Product / Banking - Spring Boot, Claude/Codex also essential. *YOU MUST HAVE BEEN INVOLVED IN DESIGN, ARCHITECTURE AND BUILD OF ANY FINTECH PRODUCT* for e.g. Current Account OR SAVINGS OR ISA's OR Fixed Term Deposits, Lending, Mortgages etc. £600-£650/DAY OUTSIDE IR35 PAY. Our Fintech Challenger Bank client based in Central London seeks a dynamic, eager to learn and technically astute Java Software Engineer who has extensive experience in Designing & Building a Payment Product *NOT PAYMENT PLATFORM* so the ideal candidate will come from for e.g. a Challenger Bank or Fintech Payment Product Company. STRONG skills in Java, Spring Boot, AI (Claude or Codex), working in a Fintech Payment domain. YOU WILL NOT BE CONSIDERED IF YOU DO NOT HAVE FINTECH & DESIGN & BUILD PAYMENT PRODUCT EXPERIENCE WITH JAVA, SPRING & STRONG AI! Our client is hiring a hands-on SENIOR Software Engineer / Java...

Software Engineer/AI Engineer Fintech & Payments Domain. £600-£650/day LTD CO OUTSIDE IR35 PAY 1-2 days onsite London. Our Fintech Financial Service/Banking & Payment Service Client based in Central London seeks a proactive, hands-on Senior Software Engineer & AI Engineer with Claude or Codex & Java Development skills, with a particular importance to solid expertise in Claude or Codex AI Tooling, Agentic AI, Java Development using Spring Boot within a Fintech Payment Domain setting. YOU WILL NOT BE CONSIDERED IF YOU DO NOT HAVE FINTECH & PAYMENTS & JAVA & STRONG AI! The ideal candidate MUST HAVE previous experience working in a startup/scaleup Fintech Financial Services environment. Any ISA product implementation/integration experience is an advantage but not essential. AI skills in Codex, Claude is highly sought as my client is looking for someone who is an AI Enthusiast. Our client is hiring a hands-on Software Engineer/Java Developer to support...

Senior/Lead Software Engineer (Java) | Outside IR35 | Hybrid (2 Days Onsite in central London) A large retailer urgently seeks an experienced Senior Software Engineer with extensive Java expertise to take a lead role in the design,development and support of scalable, cloud-native Back End applications. Working within an Agile, DevOps environment, you'll help build high-performance microservices, APIs and event-driven solutions powering a next-generation fulfilment platform used at significant scale. This is an exciting greenfield programme, working alongside engineers, operations and product teams to deliver software that supports critical business operations. Essential Experience Extensive commercial experience developing enterprise applications with Java and Spring Boot Proven track record designing and delivering high-throughput, distributed microservices at scale Strong experience building event-driven architectures using Kafka Expertise with PostgreSQL and...

Senior Software Engineer (C++) - Contract Join a globally recognised technology business supporting one of the world 's leading online gaming platforms. This is an opportunity to work on a large-scale, business-critical C++ platform, helping modernise legacy systems while supporting a major cloud migration programme. Role Overview Location: Remote, must be based in UK Package: £600 - £650pd Outside IR35 Duration: 3 months (Sept - Dec) Industry: Technology / iGaming What You'll Be Doing Develop high-quality C++ within a large, established production codebase. Play a key role in migrating core platform capabilities from Windows to Linux as part of a wider modernisation programme. Refactor and modernise legacy components while maintaining stability and existing functionality. Build and enhance high-performance, low-latency, server-side systems supporting a live platform. Integrate platform services with AWS where required as...

Senior Mobile Engineer Tech: Kotlin / Swift / Flutter / BLE / NFC Location: Hybrid (Angel, London – 2 - 4 days per month in office) Contract: Outside IR35 (client is exempt) Duration: 8–12 weeks Start: ASAP Rate: £400 - £525 per day The Opportunity: We're partnering with an innovative IoT technology business looking for a Senior Mobile Engineer to lead the build of a brand-new mobile activation app and SDK. This is a greenfield project, replacing a legacy application with a lightweight solution focused on BLE, NFC and background scanning for enterprise customers. You'll own the project from architecture through to delivery, working directly with the Head of Software in a fast-moving, engineering-led environment. What You'll Do: Build a new mobile app and SDK from scratch Develop BLE background scanning and NFC activation Work on both native iOS and native Android and use Flutter for some basic UI screens. Deliver production-ready...

Azure | Databricks | SQL | Outside IR35 | Hybrid THE COMPANY We 're partnering with a global mining organisation that is investing heavily in the evolution of its enterprise data platform. Following significant growth and a wider transformation programme, they 're looking to bring in an experienced Senior Data Engineer to strengthen the technical capability of the team and support the delivery of several high-profile data initiatives. This is a business that places real value on engineering best practice and is looking for someone who can provide immediate technical expertise, influence engineering standards through delivery and help solve complex data engineering challenges across the organisation. THE ROLE This is a hands-on Senior Data Engineering contract where you 'll operate as a senior individual contributor within a highly collaborative team. Rather than leading people, you 'll lead technically, owning complex engineering problems, partnering with...

Senior Infrastructure Engineer - Central London £550 - £600 p/d (outside IR35) 3 month initial contract A leading engineering business is seeking a Senior Infrastructure Engineer to join their team. They are a well-established business about to enter a period of considerable operational change, including merger and acquisition activity, making it an exciting time to join and be part of their journey. Reporting into the Infrastructure Manager, you will oversee core infrastructure and networking. You'll work closely with managed service providers to ensure seamless operations and business continuity, whilst taking a lead on regular site set-ups and supporting infrastructure integration across newly acquired entities. Key Responsibilities: Lead and manage office and site networks, aligning with business strategy Act as an escalation point for the Service Desk Team Set up and configure Local Area Networks (LANs), including hardware deployment and support Coordinate with...

🚨 Active DV Cleared Full Stack Engineers 🚨 I'm working with a leading UK defence client on a major AI programme and am looking to speak with experienced DV Cleared Full Stack Engineers for a long-term contract opportunity. The Role 12-month contract Outside IR35 £500–£600 per day London (4 days onsite) You'll be joining a multidisciplinary engineering team delivering secure, mission-critical software on one of the UK's most exciting defence programmes. We're keen to hear from engineers with experience in areas such as: Python Java React MongoDB AI / Machine Learning Kubernetes VMware AWS or Azure Essential: Active UK DV Clearance Happy to work onsite in London four days per week If you're looking for your next contract within the defence sector, I'd be happy to tell you more.

AI SOFTWARE ENGINEER - DV CLEARED BRAND NEW OUTSIDE IR35 CONTRACT OPPORTUNITY AVAILABLE WITH A LEADING NATIONAL SECURITY CONSULTANCY FOR AN AI SOFTWARE ENGINEER Contract opportunity for an AI Software Engineer Outside IR35 Day rate up to £650 Hybrid role - London Must hold active UKSV DV clearance To apply please email or call WHO WE ARE? We are working with a specialist consultancy delivering cutting-edge AI and software solutions into the UK National Security and Defence sector. Due to continued growth and the expansion of several mission-critical programmes, we are looking for an experienced AI Software Engineer to join a high-performing engineering team in London. WHAT WILL THE AI SOFTWARE ENGINEER BE DOING? You will be designing and building AI-enabled software systems that support complex operational environments. The role will involve developing scalable backend services, integrating machine learning models into production...

Role: Programme Test Lead Rate: £500 p/d Outside IR35 Location: Fully remote Duration: 2 months We are seeking an experienced Programme Test Lead to oversee testing activities across a complex portfolio of technology initiatives. You will be responsible for defining and delivering programme-level test strategies, managing testing risks, coordinating multiple delivery teams, and ensuring high-quality releases across the software delivery lifecycle. Working closely with technology, product, and business stakeholders, you will play a critical role in ensuring delivery excellence and business confidence. Key Responsibilitie sDefine and implement the overall testing strategy, standards, and best practices .Lead, mentor, and develop a team of QA Engineers and Test Leads .Oversee test planning, estimation, execution, and reporting across multiple projects .Ensure appropriate test coverage through functional, regression, integration, performance, and automation...

Senior Full Stack Developer AI-Assisted Development Outside IR35 Contract / Central London Avanti Recruitment is working with a growing technology business looking for a Senior Full Stack Developer to help build a suite of modern web applications that are central to its future technology strategy. You 'll be working across React, TypeScript and Node.js, taking ownership of features from concept through to production in a fast-paced, collaborative engineering team. We 're looking for engineers who already use AI coding tools such as Claude Code, Cursor, GitHub Copilot or Codex as part of their everyday development workflow. This isn 't an AI engineering role, it 's about using AI to build great software more effectively. Requirements: Strong commercial experience with React, TypeScript and Node.js Experience building modern web applications or SaaS products Product-focused mindset with strong problem-solving skills Comfortable using...