32 senior software engineer jobs found in London, greater london

Senior Software Engineer - Pricing & Availability (Node/React/.Net) We're supporting a high-traffic global travel and E-commerce platform in its search for a Senior Software Engineer to strengthen its pricing and availability systems. This is a hands-on contract role focused on improving the performance, reliability and scalability of a complex transactional platform processing millions of customer searches across multiple international markets. What you'll be working on: Building and improving pricing, quote-caching and availability services Designing resilient APIs and integration patterns Tackling latency, performance and infrastructure cost challenges Managing the trade-off between pricing freshness and cache efficiency Improving observability through monitoring, tracing and meaningful metrics Working alongside teams responsible for third-party integrations and booking systems Using AI coding tools as part of your day-to-day engineering workflow What...

Senior Software Engineer - Pricing & Availability (Node/React/.Net) We're supporting a high-traffic global travel and e-commerce platform in its search for a Senior Software Engineer to strengthen its pricing and availability systems. This is a hands-on contract role focused on improving the performance, reliability and scalability of a complex transactional platform processing millions of customer searches across multiple international markets. What you'll be working on: • Building and improving pricing, quote-caching and availability services • Designing resilient APIs and integration patterns • Tackling latency, performance and infrastructure cost challenges • Managing the trade-off between pricing freshness and cache efficiency • Improving observability through monitoring, tracing and meaningful metrics • Working alongside teams responsible for third-party integrations and booking systems • Using AI coding tools as...

Senior Software Engineer - Pricing & Availability (Node/React/.Net) We're supporting a high-traffic global travel and E-commerce platform in its search for a Senior Software Engineer to strengthen its pricing and availability systems. This is a hands-on contract role focused on improving the performance, reliability and scalability of a complex transactional platform processing millions of customer searches across multiple international markets. What you'll be working on: Building and improving pricing, quote-caching and availability services Designing resilient APIs and integration patterns Tackling latency, performance and infrastructure cost challenges Managing the trade-off between pricing freshness and cache efficiency Improving observability through monitoring, tracing and meaningful metrics Working alongside teams responsible for third-party integrations and booking systems Using AI coding tools as part of your day-to-day engineering workflow What...

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...

ERP Integration Architect (Senior Software Engineer - Enterprise Integrations) - Contract - Outside Location: Remote (Europe) Contract: Full-time (40 hours per week) - Outside IR35 - Fully Remote About the Role: We're looking for an experienced ERP Integration Architect to join a global engineering team delivering enterprise integration solutions for large-scale customers click apply for full job details

ERP Integration Architect (Senior Software Engineer - Enterprise Integrations) - Contract - Outside Location: Remote (Europe) Contract: Full-time (40 hours per week) - Outside IR35 - Fully Remote About the Role: We're looking for an experienced ERP Integration Architect to join a global engineering team delivering enterprise integration solutions for large-scale customers. Whilst the title is ERP Integration Architect , this is a highly hands-on engineering role . We're looking for someone who enjoys designing and building integrations, developing APIs and solving complex technical challenges rather than producing high-level architecture alone. You'll be responsible for integrating ServiceNow, ERP platforms and other enterprise applications using a combination of integration technologies and bespoke software development. This role is ideal for someone who is equally comfortable using enterprise integration platforms and writing custom integration code when...

Principal Software Developer, AI Integration, C#, £550 day rate, Outside IR35, Reading, COR7630 We're looking for an experienced Principal Software Developer to join a long-term contract with an initial 3-month term and a strong likelihood of extension up to 18 months. This role is based in Reading, with three days per week onsite, and offers a day rate of up to £550 , outside IR35. As a Principal Software Developer, you'll play a key role in driving the adoption of AI within a software engineering team. Working closely with developers, you'll help integrate AI-powered tools and agentic technologies into the development lifecycle, improving productivity and modernising engineering practices. What's required of the Principal Software Developer? Strong commercial experience developing software with C# and .NET Experience leading or supporting the adoption of AI within a software development team Knowledge of AI-assisted development tools, such as Claude, GitHub Agents,...

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...

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 backend 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...

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 / 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 backend 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...

Senior Geospatial Engineer | Outside IR35 | Remote SR2 are looking for a Senior Geospatial Engineer to support the development of scalable spatial data solutions for a cloud-based, data-driven platform. You'll join a cross-functional team, taking ownership of the pipelines and services used to ingest, process, validate, store and publish complex geospatial datasets. The Role You'll design and build robust geospatial workflows capable of handling data at scale. The role combines geospatial engineering, software development and cloud delivery, with the opportunity to influence technical standards, architecture and engineering best practice. Key responsibilities will include: Building pipelines for the ingestion, transformation, validation and publication of spatial data Developing scalable geospatial services and processing workflows Working with traditional and cloud-native spatial formats Consuming and publishing data through REST and OGC APIs Optimising spatial...

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...

At Mindera, we craft software with people we love. We're looking for a Principal Java Engineer with strong Retail experience who can join our crew! Please note: This is a six month contract that sits outside IR35. You will be required to work in Paddington 3 days a week. What does the role involve? Lead technical deep dives and knowledge sharing in the teams, anticipating challenges and proposing solutions Start influencing product and business decisions Hands-on Software Development: Write high-quality Java code using frameworks such as Spring Boot or Micronaut Build robust services that support secure, high-volume payment transactions Develop integrations with acquiring banks, payment gateways, and fraud detection tools Cloud & DevOps Practices: Build and support cloud-native systems on the cloud (preferably Azure) using Terraform and Kubernetes Manage CI/CD pipelines using GitHub Actions and ensure smooth delivery to production Own...

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...

Senior / Lead Software Engineer (Java) - o/s IR35 - Hybrid (2 dpw in office) A large retailer urgently seeks an experienced Senior Software Development Engineer to take a lead role in the design, development and support of scalable, cloud-native Java applications Working in an Agile, DevOps environment, you'll build microservices, APIs and event-driven solutions while collaborating with engineers, data scientists and operations teams to deliver high-quality software. The role is outside IR35 and requires 2 days per week in the office. Responsibilities include: Design and develop scalable Java applications and microservices Build and maintain cloud-native solutions using Azure Improve system performance, reliability and scalability Develop APIs and event-driven services with Kafka Mentor engineers and promote engineering best practices Support software throughout its full lifecycle in a CI/CD environment Essential Experience Experience of designing and...

🚀 Senior Front-End Engineer – Investment Banking | Contract Upto £800 p/d (Outside IR35) | London / Hybrid (1 Day/Week in Office) We are partnering with a global investment bank to hire a Senior Front-End Engineer to join a flagship team delivering a next-generation, single-page application (SPA) platform for high-performance derivatives trading. This is a high-profile role on a mission-critical, front-office system with exceptional technical standards. You’ll work at the cutting edge of financial technology, contributing to a modern, reactive web platform used across trading desks. This is not your typical enterprise UI – it’s fast, data-intensive, and built to scale with real-time demands in a trading environment. 💼 The Opportunity Collaborate with elite engineers on a SPA used across the investment bank for derivatives trading. Build elegant, high-performance UIs with real-time data updates and functional programming paradigms. Shape a front-end...