85 senior software engineer jobs found

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...

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,...

Senior Embedded Software Developer - Aerospace - Outside IR35 Contract, Hybrid (Gloucestershire) £depending on experience / expectations Aerospace, Embedded, ARM, Firmware, Software Leading aerospace company are seeking Senior Embedded Software Developer to support expanding project in controls and bare-metal engineering within cutting edge aerospace technologies. Experience: Circa 10+ years in the software development life cycle, including at least 5 years within aerospace (DO-178B/C) or another safety-critical domain. Skills Proficiency in embedded C, bare-metal programming with microcontrollers, and familiarity with MISRA C standards. Knowledge of software architecture, requirement analysis, requirement flow-down, and detail design. Solid understanding of software testing methods. Desirable Skills Knowledge of CAN, UART, SPI eand other communication protocols, Working knowledge of ARM microcontrollers, and ability to read basic electronic schematics. Experience...

Senior Software Test Engineer/Test Lead - Outside IR35 Contract: 12 months We are seeking an experienced Senior Software Test Engineer/Test Lead to support the delivery of major and maintenance software releases. This is a hands-on role involving test strategy, requirements analysis, manual and automated testing, system integration, defect management, and quality reporting. You will work closely with software, hardware, and firmware engineers within a cross-functional Agile environment. Key Responsibilities Define test strategies, test plans, and test coverage. Analyse requirements and design, execute, and maintain test cases. Lead system, regression, and hardware-software integration testing. Develop and maintain automated test scripts using C# and Ranorex . Use Azure DevOps for test management, work tracking, defect logging, reporting, and traceability. Test software integrated with physical hardware, devices, and firmware. Manage defects,...

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...

Contract AI Engineer (Claude Code Specialist) Greater Manchester (2-3 days onsite per week) Outside IR35 3 - 6 months (with view to extend) Competitive Market Rate (dependent on experience) ASAP The Role We are seeking an experienced Contract AI Engineer (Claude Code Specialist) to lead the integration and optimisation of Anthropic's Claude Code ecosystem into our development workflows. You will build, fine-tune, and deploy agentic AI coding assistants to accelerate our software delivery. Key Responsibilities Requirements Local to or able to commute to Greater Manchester 2-3 days a week. Experience with automated testing and continuous integration tools. Strong programming skills (Python, TypeScript, or Go preferred). Deep understanding of LLM architectures, prompt engineering, and context management. Direct hands-on experience deploying and configuring Claude Code or similar agentic coding tools. Proven track record as an AI Engineer or...

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...

Greetings from Response Informatics We are currently hiring a Dot net Developer for an exciting client engagement. Role: Dot net Developer Location: Taunton, UK (3 days' travel per month) Positions: Contract (Outside IR35) Clearance: Active SC Clearance Mandatory Please ensure: CV is a maximum of 3 pages Font size: 11 We are seeking an experienced Senior Software Engineer to design, develop, and maintain click apply for full job details

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...

Role: QA Test Engineer Location: Fully Remote (UK Based) Type: Contract (Outside IR35) Duration: Initial 6 months Security Clearance: SC Clearance preferred, or eligible to obtain SC Clearance About the Role We are seeking two highly experienced Senior QA Engineers to play a pivotal role in a major new programme delivering complex, data-intensive systems . This is an opportunity to take ownership of quality across the full software life cycle, ensuring robust testing, data validation, and formal acceptance processes are Embedded from the outset. The successful candidate will work within a highly autonomous engineering team, helping to define quality standards, test strategies, and automated frameworks while validating large-scale data processing and streaming solutions. This role goes beyond traditional software testing and requires an individual who can take ownership of quality assurance, challenge assumptions, and build the evidence needed to support...

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...