19 senior backend developer jobs found in London, greater london

Who Are We? Xcelirate develops technologically-advanced platforms which are accessed by thousands of users every minute! We are proud to offer a workplace where the sharpest developers come together to strategically plan and swiftly execute practices which see us maintain our existing market dominance and attain global expansion. We owe our success to our customers who have seen us grow across a decade, and our talented team who have made that growth possible!   What are we looking for? You're a Principal-Level Engineer first. The tech lead title is almost incidental. It just means you're the person the team orbits around, because that's what happens naturally when you're the one who understands the system most deeply and keeps the clearest head under pressure. The 10% that's people management fits inside your engineering work, not alongside it. You hire, you steer, you unblock, but you do it the way a strong engineer does everything: with good...

About us Founded in 2019 and part of Y Combinator's 2020 cohort, Photoroom is the leading visual solution for e-commerce. We've raised Series B funding and reached 300+ million users worldwide, processing over 5 billion images annually and serving both small businesses and major enterprises like Amazon, DoorDash, and Decathlon through our mobile app, web platform, and API. We're a remote-friendly team of 100+ passionate builders giving e-commerce businesses superpowers to create visuals that help them grow, making the hardest parts of selling online disappear. We focus on craft, innovation, and collaboration, creating exceptional impact for e-commerce businesses worldwide. Python Engineer – Public API (Contract) Day rate: Negotiable Duration: 6 months Location: Remote. We can hire people already based in selected countries only: France, Germany, Ireland, Italy, Portugal, Spain, UK   About the Role You will design,...

Who Are We? Xcelirate develops technologically-advanced platforms which are accessed by thousands of users every minute! We are proud to offer a workplace where the sharpest developers come together to strategically plan and swiftly execute practices which see us maintain our existing market dominance and attain global expansion. We owe our success to our customers who have seen us grow across a decade, and our talented team who have made that growth possible!   What are we looking for? You're a Principal-Level Engineer first. The tech lead title is almost incidental. It just means you're the person the team orbits around, because that's what happens naturally when you're the one who understands the system most deeply and keeps the clearest head under pressure. The 10% that's people management fits inside your engineering work, not alongside it. You hire, you steer, you unblock, but you do it the way a strong engineer does everything: with good...

About us Founded in 2019 and part of Y Combinator's 2020 cohort, Photoroom is the leading visual solution for e-commerce. We've raised Series B funding and reached 300+ million users worldwide, processing over 5 billion images annually and serving both small businesses and major enterprises like Amazon, DoorDash, and Decathlon through our mobile app, web platform, and API. We're a remote-friendly team of 100+ passionate builders giving e-commerce businesses superpowers to create visuals that help them grow, making the hardest parts of selling online disappear. We focus on craft, innovation, and collaboration, creating exceptional impact for e-commerce businesses worldwide. Python Engineer – Public API (Contract) Day rate: Negotiable Duration: 6 months Location: Remote. We can hire people already based in selected countries only: France, Germany, Ireland, Italy, Portugal, Spain, UK   About the Role You will design,...

Who Are We? Xcelirate develops technologically-advanced platforms which are accessed by thousands of users every minute! We are proud to offer a workplace where the sharpest developers come together to strategically plan and swiftly execute practices which see us maintain our existing market dominance and attain global expansion. We owe our success to our customers who have seen us grow across a decade, and our talented team who have made that growth possible!   What are we looking for? You're a Principal-Level Engineer first. The tech lead title is almost incidental. It just means you're the person the team orbits around, because that's what happens naturally when you're the one who understands the system most deeply and keeps the clearest head under pressure. The 10% that's people management fits inside your engineering work, not alongside it. You hire, you steer, you unblock, but you do it the way a strong engineer does everything: with good...

About us Founded in 2019 and part of Y Combinator's 2020 cohort, Photoroom is the leading visual solution for e-commerce. We've raised Series B funding and reached 300+ million users worldwide, processing over 5 billion images annually and serving both small businesses and major enterprises like Amazon, DoorDash, and Decathlon through our mobile app, web platform, and API. We're a remote-friendly team of 100+ passionate builders giving e-commerce businesses superpowers to create visuals that help them grow, making the hardest parts of selling online disappear. We focus on craft, innovation, and collaboration, creating exceptional impact for e-commerce businesses worldwide. Python Engineer – Public API (Contract) Day rate: Negotiable Duration: 6 months Location: Remote. We can hire people already based in selected countries only: France, Germany, Ireland, Italy, Portugal, Spain, UK   About the Role You will design, build, and...

Straive is a global leader in enterprise-grade data analytics and AI solutions, committed to empowering businesses across various industries with cutting-edge technology and expert insights. Backed by EQT, a top private equity firm, we are uniquely positioned to drive innovation through significant investments and an entrepreneurial spirit.   Our core focus is on delivering advanced Data Analytics & AI Solutions. By combining sophisticated technology with subject matter expertise, we deliver material impact on our clients' topline and streamline their operations. We specialize in providing tailored solutions across financial services, CPG, legal, pharma, life sciences, retail and logistics, helping them build robust data analytics and AI capabilities.   With a client base spanning 30 countries, Straive's strategically located teams operate from eight countries and is headquartered in Singapore. This global presence enables us to offer localized...

Methods is looking for a Back End Developer specialising in Java Spring Boot and GCP(Google Cloud Platform) to join our team within the private Sector Business unit. Rate: £490 inside IR35 Duration: 6 month initially Location: Hybrid; 3days/w in London office   Requirements:   Architectural Rebuild: Play a role in migrating and rebuilding our core architecture in Java Spring Boot to align with a composable, cloud-native landscape. Connector Development: Design and optimize technical connectors for a diverse mix of global channels, including generalist marketplaces, social commerce (eg, TikTok Shop), and quick-commerce (eg, Glovo, Deliveroo). Catalog Publication Flow: Refocus efforts on rebuilding the catalog publication flow, addressing technical complexities such as category mapping, product variant synchronization, and asynchronous marketplace APIs. Business Logic Migration: Collaborate on transferring complex Legacy...

Must have skills: Demonstrable experience with Solidity. Strong understanding of blockchain security practices and potential vulnerabilities. Proficiency in Hardhat and Foundry. Experience with Solidity security testing tools like Slither, Mythril, Echidna Practical experience with scripting languages like Javascript or Typescript. Ability to craft unit, integration, fork, and invariant tests, ensuring code longevity. Demonstrable aptitude for best development practices, data structures, algorithms, and methodologies. Bachelor's degree in Computer Science, Engineering, or a related STEM discipline. Excellent debugging and troubleshooting skills. Strong written and verbal communication skills. Self-motivated with the ability to work in a fast-paced, evolving environment. Proficient communication skills in English. Development background in sectors such as banking, finance, or trading, paired with a comprehensive grasp of financial...

SC Clearance is an essential requirement for this role, as a minimum you must be willing & eligible to undergo checks. Please note, due to the exceptional requirements of this position (short-term nature of this role and speed at which we require a postholder in situ) preference may be given to candidates who meet all of the essential criteria and hold active SC clearance.    The Ministry of Justice (MoJ) priorities include improving public safety and reducing reoffending by reforming prisons, probation and youth justice, and building a justice system which makes access to justice swifter and more certain for all citizens whatever their background. Project professionals in the MoJ help to improve the government's ability to protect the public and reduce reoffending, and to provide a more effective, transparent and responsive criminal justice system for victims and the public.   As a  Lead Developer , your main responsibilities will be:...

Senior QA Engineer - Mobile Applications Location: London, UK Working Mode: 3 days a week on site, London   Description We're looking for a Senior Quality Engineer - Mobile Applications to join our team in London, UK, in a hybrid working model. In this role, you will ensure the quality of mobile products that serve millions of global users. You will work in a fast-paced environment as part of a collaborative engineering team focused on delivering high-quality, intuitive mobile applications. This position combines strong technical testing skills with a creative mindset and an interest in emerging technologies, including AI-driven testing practices.   Responsibilities Design, develop, and maintain automation test strategies and scripts for iOS and Android applications using Espresso (Android) and XCUITest (iOS) Collaborate with product, design, and development teams to define testing requirements and strategies Execute functional,...

Join Secure Code Warrior to create a safer digital landscape by assisting companies to secure their software through developer-led practices!   Secure Code Warrior’s mission is to establish new standards for coding that transform the ways software is created. We do this by providing the world’s leading agile learning platform that delivers the most effective secure coding solution for developers to learn, apply, and retain software security principles. More than 600 enterprises trust Secure Code Warrior to implement agile learning security programs, build safer software, and create a culture of developer-driven security. We are a venture-backed company with offices in Australia, the United States, Belgium, Iceland, and the United Kingdom.   Secure Code Warrior is seeking a Senior Engineer to take long-term ownership of our core system-level product suite across Windows and macOS. In this contract role, you will be the architectural...

Must have skills: Demonstrable experience with Solidity. Strong understanding of blockchain security practices and potential vulnerabilities. Proficiency in Hardhat and Foundry. Experience with Solidity security testing tools like Slither, Mythril, Echidna Practical experience with scripting languages like Javascript or Typescript. Ability to craft unit, integration, fork, and invariant tests, ensuring code longevity. Demonstrable aptitude for best development practices, data structures, algorithms, and methodologies. Bachelor's degree in Computer Science, Engineering, or a related STEM discipline. Excellent debugging and troubleshooting skills. Strong written and verbal communication skills. Self-motivated with the ability to work in a fast-paced, evolving environment. Proficient communication skills in English. Development background in sectors such as banking, finance, or trading, paired with a comprehensive grasp of financial...

Novatus is a Series B scale-up RegTech SaaS provider and boutique advisory practice, enabling financial services firms to solve complex challenges and redefine what’s possible through expert-led technology and consulting. Across both our technology and consulting services, Novatus delivers practical solutions to some of the most complex regulatory, data and operational challenges in financial services.   Our SaaS platform, En>ACT ( short for Ensuring Accurate, Complete and Timely reporting ), is a market-leading solution for regulatory transaction reporting and reconciliation, providing real-time, independent oversight of transaction reporting across all global regulatory regimes. En>ACT is the only real-time assurance solution that tests 100% of transactions and 100% of fields, replacing sample-based reviews and static PDF reports delivered months after the event with live, actionable insights. This helps firms remediate quickly, reduce risk, and meet...

We are seeking a passionate Software Engineering Manager who will provide technical expertise and operate with excellence. Being creative, curious, and confident, you will be an integral part of our empowered, self-managing, multi-disciplinary engineering teams - designing, building, releasing, and maintaining products. You will play a key role in driving our ambition to create a best-in-class software engineering team, environment, and culture. This is an initial 6 month contract (outside IR35) that requires you to work on client site 3 days a week in London, Paddington. Your key accountabilities will include: • Team Management: Build, mentor, and manage a high-performing software engineering team. Foster a culture of collaboration, innovation, and continuous improvement within the team. Facilitate communication and collaboration among team members. Ensure budgets, people and resource allocation, and workload, balance across projects. • Agile Delivery: Oversee...

Join Secure Code Warrior to create a safer digital landscape by assisting companies to secure their software through developer-led practices!   Secure Code Warrior’s mission is to establish new standards for coding that transform the ways software is created. We do this by providing the world’s leading agile learning platform that delivers the most effective secure coding solution for developers to learn, apply, and retain software security principles. More than 600 enterprises trust Secure Code Warrior to implement agile learning security programs, build safer software, and create a culture of developer-driven security. We are a venture-backed company with offices in Australia, the United States, Belgium, Iceland, and the United Kingdom.   Secure Code Warrior is seeking a Senior Engineer to take long-term ownership of our core system-level product suite across Windows and macOS. In this contract role, you will be the architectural...

Must have skills: Demonstrable experience with Solidity. Strong understanding of blockchain security practices and potential vulnerabilities. Proficiency in Hardhat and Foundry. Experience with Solidity security testing tools like Slither, Mythril, Echidna Practical experience with scripting languages like Javascript or Typescript. Ability to craft unit, integration, fork, and invariant tests, ensuring code longevity. Demonstrable aptitude for best development practices, data structures, algorithms, and methodologies. Bachelor's degree in Computer Science, Engineering, or a related STEM discipline. Excellent debugging and troubleshooting skills. Strong written and verbal communication skills. Self-motivated with the ability to work in a fast-paced, evolving environment. Proficient communication skills in English. Development background in sectors such as banking, finance, or trading, paired with a comprehensive grasp of financial...

Role Summary   Wagglyn is seeking an experienced OMS / Trading Systems Engineer – Contractor to work with the existing engineering team on the design and implementation of the order management and execution control layer underpinning our low-latency FX trading platform.   This is a hands-on engineering role focused on building the core trading state and execution orchestration layer for a systematic FX trading platform operating across multiple brokers, venues, accounts, and execution routes.   The OMS layer acts as the canonical source of truth for trading state, execution workflow, position attribution, and operational controls across the platform.   You will work closely with the CTO and engineering team to design deterministic, production-ready systems capable of operating reliably under real market conditions.   This role is not suited to generic backend developers or UI-focused engineers.  ...

Contract - Full Stack Developer (React, Java, Spring) Job description Job Title: Full Stack Developer (Java, Spring, React) - contract Location: London Hybrid. Travel to the London office on 3 days a week Duration: 11 months Contract Start Date: ASAP *note client onboarding takes 6 weeks from offer Day Rate: Competitive (Inside IR35) Deloitte Working with the Deloitte Associate (Contractor) Programme means we can offer you the opportunity to work on a variation of industry and client related projects. Our aim is to retain the best talent and so when your project end date nears our team of Talent Community Advisors will be working with you to look at alternative projects within the firm that suit your experience should you wish to continue with Deloitte. The Role We are looking for an experienced Full Stack Developers to work in the Technology and Transformation Team at Deloitte. You will work with one of our global financial services clients. This position...