48 software engineer jobs found in London

Project is integration multiple 3rd party services into a financial services platform. Looking for front end (React Native) or Back end (.net) experience (Or both) Start date ASAP Duration 3 months (Likely to extend) 2 days / week in person working (London) Joining a cross functional team of 12 Immediate Interviews     The best bit about Red Badger is, of course, the team. We are really proud of our people; we support and learn a lot from each other; we work really hard but have fun doing it. We are a diverse group made up of 22 different nationalities, speaking 17 different languages.     Our 3 founders, Dave, Cain and Stu, who have considerable tech and consultancy experience and still own 100% of the company. We've been consistently profitable and have grown responsibly from the beginning.     We are based at Old Street in the heart of "tech city" and get thoroughly stuck in with the...

Full Stack Software Engineer (AI/ML Platform) Location: London (Hybrid/On-site as needed) Rate: Up to £650 per day Contract: Outside IR35 Positions: 2 roles available SR2 are working with a fast-growing AI scale-up in London that's building next-generation machine learning platforms used at serious scale. They're looking for two experienced Full Stack Software Engineers to help design, build, and scale production-grade AI-driven systems. What you'll be working on Building high-performance, user-facing applications using React and TypeScript Designing and developing scalable Python backends powering ML-driven products Integrating machine learning models into real-world production systems Working on data pipelines, inference services, and model-serving APIs Improving system performance, reliability, and scalability in a fast-moving environment Shipping features quickly while maintaining clean, testable, production-quality code Core tech stack Frontend React...

Principal Software Engineer (React & Java) – Contract Rate: Up to £700/day (Outside IR35) Location: UK Remote / Hybrid (Public Sector) Duration: Initial 6 months Clearance: SC eligible (active not required) Notice: Under 1 month preferred We’re working with a consultancy delivering a large-scale cloud transformation and modernisation programme across a public sector application portfolio. The focus is on modernising legacy systems, enabling cloud-native services, and laying the groundwork for AI and generative capabilities , all within AWS. They’re looking for a Principal-level Software Engineer who can operate as a hands-on technical leader. The Role Lead a small team of contractors (2+ already in place) Drive technical direction across React and Java-based services Hands-on delivery (approx. 80% engineering / 20% leadership ) Own design decisions, code quality, and best practices Contribute to modernisation strategy and cloud-native...

Principal Software Engineer (React & Java) - Contract Rate: Up to £700/day (Outside IR35) Location: UK Remote/Hybrid (Public Sector) Duration: Initial 6 months Clearance: SC eligible (active not required) Notice: Under 1 month preferred We're working with a consultancy delivering a large-scale cloud transformation and modernisation programme across a public sector application portfolio. The focus is on modernising Legacy systems, enabling cloud-native services, and laying the groundwork for AI and generative capabilities , all within AWS. They're looking for a Principal-level Software Engineer who can operate as a hands-on technical leader. The Role Lead a small team of contractors (2+ already in place) Drive technical direction across React and Java-based services Hands-on delivery (approx. 80% engineering/20% leadership ) Own design decisions, code quality, and best practices Contribute to modernisation strategy and cloud-native...

AI Software Engineer - Contract (SC Cleared) Location: London (Hybrid Working) Contract: Outside IR35 Clearance: Active SC Clearance required Email : Phone : Overview We are seeking an experienced AI Software Engineer to join a high-impact programme based in London , working on cutting-edge AI and LLM-driven solutions. This is an outside IR35 contract offering hybrid working , ideal for contractors with strong experience building production-grade AI systems in cloud environments. You will play a key role in designing, developing, and deploying AI-powered applications using modern frameworks and cloud-native technologies. Key Responsibilities Design and develop AI-driven applications using LLMs and agent-based architectures Build and integrate workflows using LangChain and/or LangGraph Develop robust backend services using Python Contribute to frontend or full-stack...

CONTRACT SENIOR SOFTWARE ENGINEER - eDV CLEARED NEW CONTRACT JOB OPPORTUNITY AVAILABLE WITHIN A LEADING NATIONAL SECURITY COMPANY FOR A SENIOR SOFTWARE ENGINEER WITH eDV CLEARANCE Contract job opportunity for a Senior Software Engineer Globally leading defence / cyber security company £500 - £750 per day (inside and outside IR35 roles available) London based organisation in an easily accessible location Contract Senior Software Engineer To apply please call or email WHO WE ARE? We are recruiting multiple contract Senior Software Engineers to work with various clients in London ranging from R &D companies, Multi-National Consultancies to SME 's and product based companies. Due to the nature of the work these clients do, you must hold enhanced DV Security Clearance. WHAT WILL THE SENIOR SOFTWARE ENGINEER BE DOING? As a Senior Software Engineer, you will work with an experienced agile team to design and deliver...

Job Title: Contract Embedded Engineer Location: Outskirts of Basildon (two days per week required on-site) Rate: up to £57pphr (outside of IR35) Duration: 6 months+ Overview: As part of the embedded engineering team, you will help develop next-generation embedded automation solutions. The role involves designing, developing, and maintaining Linux platforms on ARM-based microprocessors for reliable operation in harsh environments. You will collaborate with cross-functional teams to define specifications, deliver the product, and support its release. Knowledge needed:- 7+ years of Advanced C++- object-oriented (OOP) concepts- Experience with cross-compiling, GDB, JTAG.- Microprocessor and microcontroller architectures like Cortex-A series, ARM series, and other general-purpose microcontrollers.- Multi-threaded applications and IPC.- Good experience with Linux-Scripting languages like Shell script/Python.-Experience with communication protocols such as CAN, I2C, SPI, Serial/TCP IP....

Overview: Expleo is a trusted partner for end-to-end, integrated engineering, quality services and management consulting for digital transformation. We help businesses harness unrelenting technological change to successfully deliver innovations that will help them gain a competitive advantage and improve the everyday lives of people around the globe. The Electronics & Embedded Systems (EES) business unit has world class experts in the provision of real-time embedded systems, specialising in safety critical control systems. To continue to grow the business we are now looking for an experienced Software Engineer (C++) to join our growing team. We are a key supplier to a number of the largest defence suppliers in the UK. Opportunities are on both Permanent and Contractor (Insider & Outside IR35) working basis, typically with 3 days onsite in Stevenage, though you must be prepared for travel to client location. Responsibilities: EE requirements content, and...

Expleo is a trusted partner for end-to-end, integrated engineering, quality services and management consulting for digital transformation.  We help businesses harness unrelenting technological change to successfully deliver innovations that will help them gain a competitive advantage and improve the everyday lives of people around the globe. The Electronics & Embedded Systems (EES) business unit has world class experts in the provision of real-time embedded systems, specialising in safety critical control systems. To continue to grow the business we are now looking for an experienced Software Engineer (C++) to join our growing team. We are a key supplier to a number of the largest defence suppliers in the UK. Opportunities are on both Permanent and Contractor (Insider & Outside IR35) working basis, typically with 3 days onsite in Stevenage, though you must be prepared for travel to client location. Responsibilities EE requirements content, and...

Full job description Overview: Expleo is a trusted partner for end-to-end, integrated engineering, quality services and management consulting for digital transformation. We help businesses harness unrelenting technological change to successfully deliver innovations that will help them gain a competitive advantage and improve the everyday lives of people around the globe.   The Electronics & Embedded Systems (EES) business unit has world class experts in the provision of real-time embedded systems, specialising in safety critical control systems. To continue to grow the business we are now looking for an experienced Software Engineer (C++) to join our growing team.   We are a key supplier to a number of the largest defence suppliers in the UK. Opportunities are on both Permanent and Contractor (Insider & Outside IR35) working basis, typically with 3 days onsite in Stevenage, though you must be prepared for travel to client location....

Outside IR35 Backend Software Engineer - MOD/Defence Project, Farnborough, Hybrid, £500-550 per day Contract opportunity for a Back End software engineer for a programme involving LLM. This is for a defence consultancy and security clearance (SC) would be needed prior to engagement. Due to the nature of the role, 1-3 days per week in Farnborough is needed. Key skills required Backed development experience (Mid-senior level) Python Data Pipeline Creation and Management API Creation and Integration Database Creation and Integration Working with JSON If you have worked in a security cleared environment, have the active relevant Security Clearance and skilled with Back End development - please apply.

Embedded Software Engineer Cambridge | Outside IR35 | £550 per day | Onsite / Hybrid This is a specialist contract for an embedded engineer who knows how to work in regulated, safety-critical environments . You’ll support the development and certification of embedded software aligned to DO-178 standards, contributing to systems where assurance, traceability and correctness are as important as the code itself. The business operates in a low-ego, technically rigorous environment and values engineers who can balance compliance with pragmatic delivery. What you’ll be doing Developing and verifying embedded software in line with DO-178 (B or C) Producing certification-ready artefacts and documentation Working closely with systems, verification and quality teams Supporting audits, reviews and certification activities What you’ll bring Proven experience delivering software under DO-178 Strong embedded C/C++ background Comfortable with...

X2 Senior Backend Engineer (Node) – 6-Month Contract (Extension Likely) - £600-£700 a day - OUTSIDE IR35 FRESH has partnered with a global online media and technology company that builds communities and products reaching 100's millions people annually across iGaming, Sports Betting, and Finance. What You’ll Be Doing Take technical ownership of core platforms (NextGen & MDM), the engines powering websites Lead on design, architecture, and best practice while mentoring other engineers Collaborate with Engineering, Delivery, and Product to deliver scalable, high-quality solutions Own and expand in-house HubSpot platform (30% focus), leading its maintenance, integration, and ongoing evolution Key skills you’ll bring: Strong experience with NodeJS/TypeScript Proficiency in SQL Solid experience with AWS Ability to effectively lead and collaborate with engineering teams Interested in hearing more, hit the apply button and I'll be in contact!...

Java Developer Contract – 6 Months Outside IR35 Hybrid - 1 day per month in London office We’re looking for an experienced Java Developers to join a fast-paced engineering team on an initial 6-month contract (Outside IR35). You’ll be contributing to the development and enhancement of scalable backend systems in a collaborative, delivery-focused environment. Responsibilities Design, develop, and maintain high-quality Java applications Build and improve backend services and APIs Write clean, testable, and efficient code Collaborate with engineers, QA, and stakeholders to deliver features Participate in code reviews and technical discussions Requirements Strong commercial experience with Java Solid understanding of object-oriented design principles Experience building backend systems and APIs Familiar with unit testing and best coding practices Comfortable working in an agile development environment Ideal for a contractor who...

Java Developer Contract – 6 Months Outside IR35 Hybrid - 1 day per month in London office We’re looking for an experienced Java Developers to join a fast-paced engineering team on an initial 6-month contract (Outside IR35). You’ll be contributing to the development and enhancement of scalable backend systems in a collaborative, delivery-focused environment. Responsibilities Design, develop, and maintain high-quality Java applications Build and improve backend services and APIs Write clean, testable, and efficient code Collaborate with engineers, QA, and stakeholders to deliver features Participate in code reviews and technical discussions Requirements Strong commercial experience with Java Solid understanding of object-oriented design principles Experience building backend systems and APIs Familiar with unit testing and best coding practices Comfortable working in an agile development environment Ideal for a contractor who...

C#.NET EOS Developer (ETRM) Contract: 6 months initial (extension likely) Location: London Rate: Competitive, Outside IR35 Overview A Global energy trading organisation seeking an experienced C#.NET Developer to support and enhance EOS-focused ETRM platforms across power, gas and environmental markets. The role sits within a specialist trading technology team delivering system enhancements, integrations and ongoing optimisation in an agile environment. Responsibilities Develop and enhance EOS trading and risk applications using C#.NET (WinForms, WCF). Translate EOS trading requirements into technical solutions in collaboration with BAs and delivery leads. Design and optimise SQL Server databases supporting trading and operational workflows. Maintain code quality through testing, standards and peer review. Manage CI/CD pipelines and deployments via Azure DevOps. Support legacy and vendor/inherited codebases. Deliver against agile sprint commitments....

London, UK (Hybrid – 3 days per week on-site) Contract (£500–650 outside IR35) & Perm available (£100-120k + 10% Bonus + Equity) About the Role Join a fast-growing AI SaaS company in London as a Fullstack Python Engineer, building large-scale, data-driven systems that power intelligent automation and next-generation learning products. You’ll work on high-performance backend services, APIs, and working with frontend teams using TypeScript, Node, React and AWS, collaborating closely with data, product, and DevOps teams in a highly technical, engineering-led environment. Key Responsibilities Develop and scale backend systems and APIs using Python / Typescript Design distributed, high-throughput services and event-driven components Collaborate across teams to deploy, monitor, and optimise microservices Contribute to an engineering culture focused on performance, quality, and automation Requirements Proven experience with Python (5+ years in...

C++ Software Engineer (Contract) – £300–£400/day – Outside IR35 You'll be working for a Fintech company as an experienced C++ Software Engineer. Joining the development team on a 9‑month contract (OUTSIDE IR35) . This role focuses entirely on modern C++ engineering within a high‑performance Linux environment. You’ll work across core C++ components, toolsets, and performance‑critical systems, collaborating with senior engineers to enhance and maintain a sophisticated technical product suite. The work is varied, technical, and ideal for someone who enjoys solving low‑level and high‑performance coding challenges. This position does not require prior experience in financial services or trading systems, but if you have it, then great. If not, we are happy for you to learn this on the job. Role Responsibilities Develop modern, production‑grade C++ features and components Work with multi‑threaded, high‑performance systems Contribute to design discussions, code...

Contract Embedded Software Engineer London | Outside IR35 | £550 per day | Hybrid This contract sits within a highly capable engineering SME working on advanced, safety-critical embedded systems. The work is discreet by nature and requires engineers who are comfortable operating in environments where technical depth, pace and trust matter. You'll be joining a small, experienced team delivering embedded software that interacts directly with real hardware. The focus is on robust, production-quality code, not prototypes that never leave the lab. What you'll be doing Developing embedded software in C/C++ Working close to hardware, supporting bring-up and integration Debugging and fault-finding at system level Collaborating directly with experienced engineers across disciplines Contributing to systems where reliability and performance are non-negotiable What you'll bring Strong background in embedded software engineering Comfortable working across the full...

C++ Software Engineer – Low‑Latency Trading Contract - OUTSIDE IR35 Rate - Dependent on skills London - Hybrid working 50% in office. You'll be joining a high‑performance trading technology firm. Helping to building ultra‑low‑latency systems powering global electronic markets. Working alongside world‑class engineers solving complex challenges across C++, Linux, networking, and hardware‑accelerated trading pipelines. What You'll Do Build and optimise high‑performance, low‑latency C++ applications Develop real‑time systems interacting directly with global exchanges Work closely with FPGA, network, and infrastructure teams Improve latency, throughput, and reliability across mission‑critical systems Contribute to performance tuning, profiling, and code reviews Skills required Exceptional modern C++ (C++17/20) development experience Strong Linux systems knowledge and debugging skills Experience in low‑latency, multithreaded or high‑performance environments...