25 senior backend engineer jobs found

Why voize? Because we’re more than just a job! At voize, we believe the greatest gift to frontline workers is time - time to care, connect, and be present. Today, that time is lost to admin work that pulls nurses away from what matters most: people .   Your Mission As a Freelance Senior Backend Engineer for our German Market squad , you’ll ensure that data flows smoothly between our products and our partners' software solutions. You'll build and maintain the integrations that connect the voize with senior care and hospital software platforms. We are open for you to be based remotely across Germany, France or the UK.   Your Daily Business – No two days are alike Shape the future of our integrations – Develop interfaces that seamlessly connect voize with systems in the care and medical sector Build future-proof solutions – Develop a scalable API, set industry standards, and work closely with...

As a Freelance Senior Backend Engineer for our German Market squad , you’ll ensure that data flows smoothly between our products and our partners' software solutions. You'll build and maintain the integrations that connect the voize with senior care and hospital software platforms. We are open for you to be based remotely across Germany, France or the UK.   Your Daily Business – No two days are alike Shape the future of our integrations – Develop interfaces that seamlessly connect voize with systems in the care and medical sector Build future-proof solutions – Develop a scalable API, set industry standards, and work closely with partners and clients Take end-to-end ownership – From the idea and implementation to the ongoing development of our integrations Architecture with foresight – Design thoughtful data models and sustainable solutions for complex systems Work with impact...

Texas Sports Academy is a K-12 school designed for serious student-athletes who want both elite academics and high-level athletic development. Students learn twice as fast as traditional schools in just 2 hours a day, using the same 2-Hour Learning model as Alpha School. We are an AI-first school where AI is woven into how students learn, how the team works, and how we build and scale everything we do. That frees up their entire afternoon for serious training, where they work alongside former pro and D1 athletes coaching them at the highest standard.   We are hiring a Senior Backend Scalability Engineer on a part-time consulting contract to audit our backend systems and make the changes required to keep them fast and reliable as we scale. You will look at our services, databases, APIs, and data flows, find the bottlenecks and design flaws that will break us at the next scale step, and ship the code changes needed to fix them. You will also write clean, direct audits of...

We're looking for an experienced Backend Engineer to design and build robust, scalable microservices. You'll work across the full Back End stack - from API design through to production-grade integration testing - using modern Java and Spring technologies. Requirements Strong hands-on experience with Java 17+ and Spring Boot 3 Proven experience building and maintaining microservices architectures Practical experience with Kafka (producers, consumers, event-driven patterns) Strong understanding of REST API design best practices Proficiency with Gradle for build management Familiarity with MapStruct and Feign Working knowledge of domain-driven design (DDD) patterns An integration-testing mindset - comfortable testing services in realistic, end-to-end scenarios, not just isolated units Job responsibilities Design, build, and maintain Back End microservices using Java 17+ and Spring Boot 3 Design and implement clean, well-documented REST APIs Build...

We're looking for an experienced Backend Engineer to design and build robust, scalable microservices. You'll work across the full Back End stack - from API design through to production-grade integration testing - using modern Java and Spring technologies. Requirements Strong hands-on experience with Java 17+ and Spring Boot 3 Proven experience building and maintaining microservices architectures Practical experience with Kafka (producers, consumers, event-driven patterns) Strong understanding of REST API design best practices Proficiency with Gradle for build management Familiarity with MapStruct and Feign Working knowledge of domain-driven design (DDD) patterns An integration-testing mindset - comfortable testing services in realistic, end-to-end scenarios, not just isolated units Job responsibilities Design, build, and maintain Back End microservices using Java 17+ and Spring Boot 3 Design and implement clean, well-documented REST APIs Build...

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...

Location: London 1-2 days a week. Department: Engineering Employment Type: Contract Contract Length: 6 months (with potential for extension) About YLD: Our goal is to help our clients keep moving forward. We work with them to build the skills and capabilities they need to stay ahead of the competition, and we know our success only happens when they succeed. We’re a team of curious, talented people, and we’re committed to making YLD a place where great people want to work, grow, and stay. We’re a remote-first consultancy specialising in software engineering, product design, and data. Our teams are based across London, Lisbon, and Porto, and we create digital solutions that continue to deliver value long after our work is done. About the role: As a Senior Software Engineer at YLD, you’ll be part of a client team building innovative products. We’re looking for someone curious, passionate, driven, and...

Full job description Joining a new project Ideally have worked on Financial Services Projects before (Payments would be great) Fullstack Experience Tech Stack - Kotlin Backend, JS/TS React Frontend Start date ASAP Duration 6 months (Likely to extend) 2/3 days / week in person working (London) 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...

What if your expertise in Rust could directly shape the infrastructure behind the world's most advanced AI systems? We're looking for a Senior Rust Engineer to design and build high-performance data pipelines, annotation tooling, and evaluation systems that power cutting-edge AI research and production workflows. This is a fully remote contract role working alongside leading AI labs on real, high-impact engineering challenges — not toy projects. If you live and breathe Rust and care deeply about performance, safety, and correctness, this is the work you've been waiting for. Organization : Alignerr Type : Hourly Contract Location : Remote Commitment : 20–40 hours/week What You'll Do Design, build, and optimize high-performance systems in Rust supporting large-scale AI data pipelines and evaluation workflows Develop full-stack tooling and backend services for data annotation , validation, and quality control at scale Identify and...

Location: London (once a month) Department: Engineering Employment Type: Contract - Outside IR35 Contract Length: 6 months (with potential for extension)   About YLD: Our goal is to help our clients keep moving forward. We work with them to build the skills and capabilities they need to stay ahead of the competition, and we know our success only happens when they succeed. We’re a team of curious, talented people, and we’re committed to making YLD a place where great people want to work, grow, and stay. We’re a remote-first consultancy specialising in software engineering, product design, and data. Our teams are based across London, Lisbon, and Porto, and we create digital solutions that continue to deliver value long after our work is done.   About the role: As a Senior Software Engineer at YLD, you’ll be part of a client team building innovative products. We’re looking for someone curious,...

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...

Full job description Joining a new project Ideally have worked on Financial Services Projects before (Payments would be great) Fullstack Experience Tech Stack - Kotlin Backend, JS/TS React Frontend Start date ASAP Duration 6 months (Likely to extend) 2/3 days / week in person working (London) 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 job description Location: London 1-2 days a week. Department: Engineering Employment Type: Contract Contract Length: 6 months (with potential for extension) About YLD: Our goal is to help our clients keep moving forward. We work with them to build the skills and capabilities they need to stay ahead of the competition, and we know our success only happens when they succeed. We’re a team of curious, talented people, and we’re committed to making YLD a place where great people want to work, grow, and stay. We’re a remote-first consultancy specialising in software engineering, product design, and data. Our teams are based across London, Lisbon, and Porto, and we create digital solutions that continue to deliver value long after our work is done. About the role: As a Senior Software Engineer at YLD, you’ll be part of a client team building innovative products. We’re looking for someone curious,...

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...

Joining a new project Ideally have worked on Financial Services Projects before (Payments would be great) Fullstack Experience Tech Stack - Kotlin Backend, JS/TS React Frontend Start date ASAP Duration 6 months (Likely to extend) 2/3 days / week in person working (London) 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 brilliant community around us. We run...

Location: London 1-2 days a week. Department: Engineering Employment Type: Contract Contract Length: 6 months (with potential for extension) About YLD: Our goal is to help our clients keep moving forward. We work with them to build the skills and capabilities they need to stay ahead of the competition, and we know our success only happens when they succeed. We’re a team of curious, talented people, and we’re committed to making YLD a place where great people want to work, grow, and stay. We’re a remote-first consultancy specialising in software engineering, product design, and data. Our teams are based across London, Lisbon, and Porto, and we create digital solutions that continue to deliver value long after our work is done. About the role: As a Senior Software Engineer at YLD, you’ll be part of a client team building innovative products. We’re looking for someone curious, passionate, driven, and...

Full job description Mindera are currently looking for an experienced Tech Lead to operate within a Platform Enablement team in the retail sector. This will be a small team that looks after capabilities that are shared across products and channels. For this role, previous experience with CRMs is essential, ideally Clavio but not limited to. Requirements Strong software engineering expertise – deep backend development experience, building scalable APIs and microservices; broader experience with technologies such as Node.js, TypeScript or React is beneficial. Architecture & system design – proven ability to design and evaluate scalable services and integrations, applying appropriate architecture patterns while balancing product goals, security, reliability and long-term system health. Cloud, DevOps & Infrastructure as Code – hands-on experience building and operating cloud-native solutions in AWS, using modern CI/CD...

Are you a coding expert fluent in Python eager to shape the future of AI? Large‑scale language models are evolving from clever chatbots into powerful engines of scientific discovery. With high‑quality training data, tomorrow's AI can democratize world‑class education, keep pace with cutting‑edge research, and streamline software development for engineers everywhere. That training data begins with you—we need your expertise to help power the next generation of AI. We're looking for Python coding specialists who live and breathe algorithms, data structures, software architecture, frontend and backend development, cloud infrastructure, and systems programming—and who can do so fluently using Python. You'll challenge advanced language models on topics like asynchronous programming, RESTful API integration, memory management, object-oriented design, secure coding practices, and debugging distributed systems—documenting every failure mode so we can harden model...

Salary £400 - £425 Outside IR35 City London Province Greater London Country United Kingdom Postal Code E14 Job Description About Scrumconnect Consulting Scrumconnect Consulting is a multi-award-winning digital consultancy, recognised for delivering impactful technology solutions across UK government departments. Our work has positively influenced the lives of over 40 million UK citizens. With a strong commitment to user-centred design and agile delivery, we continue to build innovative digital services that truly make a difference. Role Purpose We are looking for an experienced Backend Developer to design, build, and maintain scalable, secure server-side services and APIs, while contributing to the adoption of Agentic AI capabilities within our engineering platform. The role sits at SFIA Level 4 : the individual works under general direction, uses discretion in resolving problems, plans and monitors their own...

Bounteous is a global AI Services firm where agentic engineering and human experience converge to deliver transformative business outcomes for the enterprise. We help organizations design, build, and scale AI-driven products, platforms, and processes. With more than 5,000 team members worldwide, Bounteous delivers AI that sticks, powering adoption and outcomes that move organizations from experimentation to true transformation. Bounteous is backed by New Mountain Capital, a New York-based growth-oriented investment firm that emphasizes business building. CyberArk Architect 3+ months rolling contract Newbury, UK About The Role We are seeking a CyberArk Architect to lead solution design for a large-scale, TSA-regulated Privileged Access Management (PAM) migration and merger consolidation programme. This is a hands-on architecture role spanning vault migration design, identity federation, and application onboarding strategy for an estate spanning thousands of accounts and...