10 senior backend developer jobs found

Systems Programmer — AI Data Pipelines About The Role What if your mastery of Rust could directly shape the infrastructure powering the world's most advanced AI systems? We're looking for a senior Rust engineer to design and build the high-performance data pipelines, annotation tooling, and evaluation systems that leading AI labs depend on to train and improve their models. This is a fully remote contract role working on real production systems — not toy projects. You'll be embedded alongside world-class data, research, and engineering teams, solving hard systems problems that have a direct impact on the trajectory of AI development. 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...

Backend Developer — AI Data Services About The Role What if your C# expertise could directly shape the infrastructure powering the next generation of AI? We're looking for a Senior C# Full-Stack Engineer to build and optimize the data pipelines, annotation tooling, and evaluation systems that leading AI labs depend on to train and improve their models. This is a fully remote contract role with meaningful, high-impact work — the kind where your code doesn't just sit in a backlog, it actively influences how AI systems learn and behave at scale. Organization: Alignerr Type: Hourly Contract Location: Remote Commitment: 20–40 hours/week What You'll Do Design, build, and optimize high-performance C# systems supporting AI data pipelines and evaluation workflows Develop full-stack tooling and backend services for large-scale data annotation, validation, and quality control Improve reliability, performance, and safety across...

Job Description: Project Overview We are seeking a highly skilled and certified AWS Cloud Security & Frontend Engineer to conduct an intensive and comprehensive security assessment, infrastructure mapping, functional review and technical documentation of our platform. The target delivery window is 1–2 weeks. We are looking for an all-round Full-Stack Developer to work with us 5 days a week to also cover all aspects of our websites, including frontend and backend development, AWS infrastructure, deployment, maintenance, troubleshooting, security and SEO. The role requires someone who can take ownership of our web platforms and manage their ongoing development and performance. The business operates on Amazon Web Services (AWS) infrastructure, with Next.js cloud-based web applications, integrated Machine Learning APIs and a MySQL backend database. Scope of Work & Key Deliverables Application & Frontend Security Assessment: Evaluate Next.js...

Fully remote, outside IR35 contract role until 31/05/2027 - up to £750 per day Reapit - Who are we? Reapit is the original end-to-end business technology provider for estate agencies of all sizes. We've been helping sales and lettings agents build relationships and grow their businesses for more than 25 years. Our technology empowers property professionals across Europe, the Middle East, Australia, and New Zealand to work with buyers, sellers, tenants, and landlords to deliver a dream home experience. Worldwide, over 100,000 agents across more than 15,000 branches use Reapit to run their businesses, manage properties, collect rent, engage clients, and provide outstanding customer service every time. What you'll be doing Reporting to the Director of Engineering, you'll operate as a highly senior, technically hands-on Back End engineer, Embedded into a squad and owning delivery of substantive, cloud-native services end-to-end. Ad-hoc client...

Senior AWS DevSecOps & Next.js Consultant – Security & Infrastructure Audit Project Overview We are seeking a highly skilled and certified AWS Cloud Security & Frontend Engineer to conduct an intensive and comprehensive security assessment, infrastructure mapping, functional review and technical documentation of our platform. The business operates on Amazon Web Services (AWS) infrastructure, with Next.js cloud-based web applications , integrated Machine Learning APIs and a MySQL backend database . The target delivery window is 1–2 weeks . Scope of Work & Key Deliverables Application & Frontend Security Assessment: Evaluate Next.js codebases, Server-Side Rendering (SSR) security, API routes and frontend security controls against recognised industry standards, including OWASP Top 10 and CIS Benchmarks . AWS Infrastructure & Database Audit: Conduct a comprehensive security assessment of our AWS environment,...

About Voodoo Voodoo is a consumer tech company founded in Paris in 2013, with one mission: entertain the world. Today we are 1,000 people, generating $1b+ in annual revenue, profitably. Our games and apps have passed 7 billion downloads and reach 200 million+ active users every month, making Voodoo the #3 mobile publisher worldwide in downloads, after Google and Meta. We were backed by Goldman Sachs, Tencent and GBL along the way. This position can be fully remote within CET +/-2h. Team Our Gaming team is made up of hybrid-casual, casual, and mid-core experts. Our 'Core' games team supports internal and external studios worldwide in creating, developing, and launching new hit games, whilst our 'Live' games team focuses on delivering higher engagement on our existing and successful games. Joining our Live games team means collaborating with gaming industry experts on globally renowned, enduring games while embracing exciting new entrepreneurial ventures. With...

About Voodoo Voodoo is a consumer tech company founded in Paris in 2013, with one mission: entertain the world. Today we are 1,000 people, generating $1b+ in annual revenue, profitably. Our games and apps have passed 7 billion downloads and reach 200 million+ active users every month, making Voodoo the #3 mobile publisher worldwide in downloads, after Google and Meta. We were backed by Goldman Sachs, Tencent and GBL along the way. This position can be fully remote within CET +/-2h. Team Our Gaming team is made up of hybrid-casual, casual, and mid-core experts. Our 'Core' games team supports internal and external studios worldwide in creating, developing, and launching new hit games, whilst our 'Live' games team focuses on delivering higher engagement on our existing and successful games. Joining our Live games team means collaborating with gaming industry experts on globally renowned, enduring games while embracing exciting new entrepreneurial ventures. With...

About The Role What if the code you write could directly shape how the next generation of AI understands and generates software? We're looking for Software Engineers in London to build, evaluate, and improve AI-generated code — helping train AI systems to think like real developers. You'll write solutions, review AI outputs, and provide the expert-level feedback that makes AI coding assistants smarter, safer, and more reliable. This is hands-on engineering work at the frontier of AI development — not theoretical, not bureaucratic, and not boring. This is a fully remote, flexible contract role. If you can write clean code and explain your reasoning, we want to hear from you. Organization: Alignerr Type: Hourly Contract Location: Remote Commitment: 10–40 hours/week What You'll Do Write, debug, and optimize code across a range of languages, frameworks, and problem domains Review and evaluate AI-generated code for correctness,...

About Voodoo Voodoo is a consumer tech company founded in Paris in 2013, with one mission: entertain the world. Today we are 1,000 people, generating $1b+ in annual revenue, profitably. Our games and apps have passed 7 billion downloads and reach 200 million+ active users every month, making Voodoo the #3 mobile publisher worldwide in downloads, after Google and Meta. We were backed by Goldman Sachs, Tencent and GBL along the way. This position can be fully remote within CET +/-2h. Team Our Gaming team is made up of hybrid-casual, casual, and mid-core experts. Our 'Core' games team supports internal and external studios worldwide in creating, developing, and launching new hit games, whilst our 'Live' games team focuses on delivering higher engagement on our existing and successful games. Joining our Live games team means collaborating with gaming industry experts on globally renowned, enduring games while embracing exciting new entrepreneurial ventures....

Android Developer (Contract, Outside IR35) Contract status: Outside IR35 Start date: 2nd November Contract length: To the end of December 2026, with extension possible Location: Remote first London days: Once or twice a month Who you'll be doing it for You'll join the mobile platform team on a UK government app, working on the app and the services that support it. The team builds and maintains the common parts of the app, such as login. It also brings in key features built by other teams, and manages app releases. You're engaged through hedgehog lab, a digital product consultancy and certified B Corp, also Great Place to Work certified. For 20 years we've helped public and private sector organisations through digital transformation. What you'll be doing You'll build and improve the common parts of the Android app, such as login, in Kotlin with Jetpack Compose. You'll also work on how features built by other teams fit into the app. When your...