1,026 to 1,050 of 1,324 ECMAScript Jobs in London

Python Developer - Python, Django, REST API's, AWS, JavaScript OB are partnered with a Global Financial Services company, who are looking to add a highly skilled Python Developer to their team. In this role, you'll be working their Python backend systems, developing new features and collaborating with different teams, to ensure product goals are met. Python Developer - Python, Django … REST API's, AWS, JavaScript Key Skills and Experience: Strong knowledge of Python Experience with Python frameworks (Django preferred) PostgreSQL REST API'S Docker Cloud experience (AWS preferred) Knowledge of Frontend Technologies (JavaScript, HTML, CSS) This is a hybrid role with 2-3 days a week required in a London based office Base salary of £75k-£90k depending on skills … and experience To be considered, you must be UK based Python Developer - Python, Django, REST API's, AWS, JavaScript More ❯

Python Developer - Python, Django, REST API's, AWS, JavaScript OB are partnered with a Global Financial Services company, who are looking to add a highly skilled Python Developer to their team. In this role, you'll be working their Python backend systems, developing new features and collaborating with different teams, to ensure product goals are met. Python Developer - Python, Django … REST API's, AWS, JavaScript Key Skills and Experience: Strong knowledge of Python Experience with Python frameworks (Django preferred) PostgreSQL REST API'S Docker Cloud experience (AWS preferred) Knowledge of Frontend Technologies (JavaScript, HTML, CSS) This is a hybrid role with 2-3 days a week required in a London based office Base salary of £75k-£90k depending on skills … and experience To be considered, you must be UK based Python Developer - Python, Django, REST API's, AWS, JavaScript More ❯

Principal JavaScript Performance Engineer (with C++/Java/C# exposure) Location: London (Hybrid – 2 days WFH) Salary: £150,000 - £200,000 (Permanent)pension, private healthcare, gym membership, 25 days + 8 BH holiday allowance, tech/hardware budget. A high-growth software company is building the gold standard in UI frameworks and data-intensive visualisation technology . With millions … complexity that ordinary web development never touches. What you’ll do Design and optimise a high-performance UI framework used globally in real-time applications. Push the limits of JavaScript, TypeScript, and the browser runtime to handle millions of data points smoothly. Solve deep algorithmic and architectural challenges in rendering, scalability, and memory efficiency. Own features end-to-end: design … code, test, release, and iterate. Contribute to a product used by developers and enterprises worldwide. What you’ll bring Mastery of vanilla JavaScript and TypeScript , with additional exposure to C++, Java, or C# . Strong knowledge of data structures, algorithms, and performance optimisation . Experience with frameworks like React, Angular, or Vue , and a deep understanding of DOM internals and More ❯

Principal JavaScript Performance Engineer (with C++/Java/C# exposure) Location: London (Hybrid – 2 days WFH) Salary: £150,000 - £200,000 (Permanent)pension, private healthcare, gym membership, 25 days + 8 BH holiday allowance, tech/hardware budget. A high-growth software company is building the gold standard in UI frameworks and data-intensive visualisation technology . With millions … complexity that ordinary web development never touches. What you’ll do Design and optimise a high-performance UI framework used globally in real-time applications. Push the limits of JavaScript, TypeScript, and the browser runtime to handle millions of data points smoothly. Solve deep algorithmic and architectural challenges in rendering, scalability, and memory efficiency. Own features end-to-end: design … code, test, release, and iterate. Contribute to a product used by developers and enterprises worldwide. What you’ll bring Mastery of vanilla JavaScript and TypeScript , with additional exposure to C++, Java, or C# . Strong knowledge of data structures, algorithms, and performance optimisation . Experience with frameworks like React, Angular, or Vue , and a deep understanding of DOM internals and More ❯

Principal JavaScript Performance Engineer (with C++/Java/C# exposure) Location: London (Hybrid – 2 days WFH) Salary: £150,000 - £200,000 (Permanent)pension, private healthcare, gym membership, 25 days + 8 BH holiday allowance, tech/hardware budget. A high-growth software company is building the gold standard in UI frameworks and data-intensive visualisation technology . With millions … complexity that ordinary web development never touches. What you’ll do Design and optimise a high-performance UI framework used globally in real-time applications. Push the limits of JavaScript, TypeScript, and the browser runtime to handle millions of data points smoothly. Solve deep algorithmic and architectural challenges in rendering, scalability, and memory efficiency. Own features end-to-end: design … code, test, release, and iterate. Contribute to a product used by developers and enterprises worldwide. What you’ll bring Mastery of vanilla JavaScript and TypeScript , with additional exposure to C++, Java, or C# . Strong knowledge of data structures, algorithms, and performance optimisation . Experience with frameworks like React, Angular, or Vue , and a deep understanding of DOM internals and More ❯

Principal JavaScript Performance Engineer (with C++/Java/C# exposure) Location: London (Hybrid – 2 days WFH) Salary: £150,000 - £200,000 (Permanent)pension, private healthcare, gym membership, 25 days + 8 BH holiday allowance, tech/hardware budget. A high-growth software company is building the gold standard in UI frameworks and data-intensive visualisation technology . With millions … complexity that ordinary web development never touches. What you’ll do Design and optimise a high-performance UI framework used globally in real-time applications. Push the limits of JavaScript, TypeScript, and the browser runtime to handle millions of data points smoothly. Solve deep algorithmic and architectural challenges in rendering, scalability, and memory efficiency. Own features end-to-end: design … code, test, release, and iterate. Contribute to a product used by developers and enterprises worldwide. What you’ll bring Mastery of vanilla JavaScript and TypeScript , with additional exposure to C++, Java, or C# . Strong knowledge of data structures, algorithms, and performance optimisation . Experience with frameworks like React, Angular, or Vue , and a deep understanding of DOM internals and More ❯

power a global interactive learning platform. Expect a mix of new feature development, performance optimisation, and experimentation with new ideas. End-to-end development in C#/.NET/JavaScript Collaborate directly with product, design and research teams Build and improve interactive web templates and tools Optimise performance for millions of global users Work remotely as part of a UK … based team that’s expanding steadily Tech Stack C#, .NET (Core and 8), ASP.NET MVC, JavaScript, SQL Server, HTML5, CSS, Azure, Canvas API, WebAudio API What You’ll Need Strong commercial experience in C# and JavaScript Solid understanding of modern web development and best practices A proactive, problem-solving mindset Confident communicator who can collaborate remotely Nice to have: Azure More ❯

power a global interactive learning platform. Expect a mix of new feature development, performance optimisation, and experimentation with new ideas. End-to-end development in C#/.NET/JavaScript Collaborate directly with product, design and research teams Build and improve interactive web templates and tools Optimise performance for millions of global users Work remotely as part of a UK … based team that’s expanding steadily Tech Stack C#, .NET (Core and 8), ASP.NET MVC, JavaScript, SQL Server, HTML5, CSS, Azure, Canvas API, WebAudio API What You’ll Need Strong commercial experience in C# and JavaScript Solid understanding of modern web development and best practices A proactive, problem-solving mindset Confident communicator who can collaborate remotely Nice to have: Azure More ❯

API development & integration Proficient using Latest Visual Studio, Visual Code, Source Control System such as Azure DevOps, Git, SourceTree and develop build and release pipelines Proficient in SharePoint (SPFx), JavaScript framework (React and/or Angular), Power Apps (Canvas App) and Power Automate Proficiency in programming languages such as C#, JavaScript, or PowerShell for customization and integration purposes Azure development More ❯

API development & integration Proficient using Latest Visual Studio, Visual Code, Source Control System such as Azure DevOps, Git, SourceTree and develop build and release pipelines Proficient in SharePoint (SPFx), JavaScript framework (React and/or Angular), Power Apps (Canvas App) and Power Automate Proficiency in programming languages such as C#, JavaScript, or PowerShell for customization and integration purposes Azure development More ❯

We're looking for a Senior-level Software Engineer with strong JavaScript/TypeScript skills and experience across modern web stacks. You'll be instrumental in our transition away from Drupal as we modernise and scale our platform. Tech Stack: At least 4 years commercial experience with JavaScript or TypeScript and Node Exposure of Laravel and/or Python (Django More ❯

We're looking for a Senior-level Software Engineer with strong JavaScript/TypeScript skills and experience across modern web stacks. You'll be instrumental in our transition away from Drupal as we modernise and scale our platform. Tech Stack: At least 4 years commercial experience with JavaScript or TypeScript and Node Exposure of Laravel and/or Python (Django More ❯

clinicians, scientists, and product teams. Requirements: Degree in Computer Science, Data Science, Engineering, or related field. 3+ years of backend software engineering experience. Proficient in Python and/or JavaScript (Node.js). Experience with CI/CD tools (e.g. GitHub Actions, Azure Pipelines). Familiar with Docker and microservices architecture. Solid understanding of RESTful APIs. Bonus: Experience with AI/… ML tools like Hugging Face, LangChain, or PyTorch. Tech Stack: Python/JavaScript (Node.js) Docker/Kubernetes Azure/GitHub Actions RESTful APIs/Microservices Hugging Face, LangChain, PyTorch Unfortunately, no sponsorship is available at this time. More ❯

clinicians, scientists, and product teams. Requirements: Degree in Computer Science, Data Science, Engineering, or related field. 3+ years of backend software engineering experience. Proficient in Python and/or JavaScript (Node.js). Experience with CI/CD tools (e.g. GitHub Actions, Azure Pipelines). Familiar with Docker and microservices architecture. Solid understanding of RESTful APIs. Bonus: Experience with AI/… ML tools like Hugging Face, LangChain, or PyTorch. Tech Stack: Python/JavaScript (Node.js) Docker/Kubernetes Azure/GitHub Actions RESTful APIs/Microservices Hugging Face, LangChain, PyTorch Unfortunately, no sponsorship is available at this time. More ❯

Software Engineer – NodeJS TypeScript Salary: Up to £100'000– plus bonus NodeJS, React, JavaScript, TypeScript, React Framework, NextJS, Azure, Kubernetes, Docker, Digital Investments. SQL, Harrington Starr has partnered with an innovative Digital Investment & Crypto Currency house that specialise in developing unique software systems for Crypto Trading, Risk Management and Data Systems are now in the market for a NodeJS Software … for Crypto Trading and Risk Management within the organisation. This is a Greenfield project and we are looking for a Hands on Software Engineer where you will utilise the JavaScript ecosystem. This organisation are developing cutting edge web-systems, which are being used globally and are offering the opportunity for you to play a pivotal role within the full software More ❯

Software Engineer – NodeJS TypeScript Salary: Up to £100'000– plus bonus NodeJS, React, JavaScript, TypeScript, React Framework, NextJS, Azure, Kubernetes, Docker, Digital Investments. SQL, Harrington Starr has partnered with an innovative Digital Investment & Crypto Currency house that specialise in developing unique software systems for Crypto Trading, Risk Management and Data Systems are now in the market for a NodeJS Software … for Crypto Trading and Risk Management within the organisation. This is a Greenfield project and we are looking for a Hands on Software Engineer where you will utilise the JavaScript ecosystem. This organisation are developing cutting edge web-systems, which are being used globally and are offering the opportunity for you to play a pivotal role within the full software More ❯

backends and APIs that keep everything running smoothly. The role: Develop new features and enhancements for our web-based ERP system Get hands-on with both Front End (React, JavaScript/ES6) and Back End (Java 8+, Spring Boot, PostgreSQL) Collaborate with a talented team in an agile , fast-moving environment Write clean, tested, and maintainable code Help shape our … your ideas and curiosity To apply you will need some or all of the following skills and experience: Solid Java skills (ideally Java 8+) Strong understanding of web development (JavaScript ES6, React or similar) Familiarity with Spring Boot , JPA/Hibernate , and PostgreSQL Comfortable working with APIs and version control (Git) It would also be an advantage if you have More ❯

deliver high-performance applications used by major sports clients. Key Responsibilities Develop and extend multiple React/Next.js web applications Implement new UI components with Tailwind CSS and modern JavaScript Integrate REST APIs and real-time data feeds Debug, refactor, and optimise across frontend and backend systems Manage build pipelines and deployments within AWS Collaborate with internal teams to deliver … reliable and engaging user experiences Skills & Experience Essential: 3+ years’ commercial experience in React/Next.js development Strong TypeScript and modern JavaScript (ES6+) skills Experience with Tailwind CSS or similar frameworks Familiarity with WebSockets and real-time data integration Working knowledge of Node.js or Go Experience managing AWS environments, deployments, and pipelines Desirable: Experience in sports data, gaming, or live More ❯

exploration with incredible savings. They are currently looking for a Senior Engineering Manager to lead their existing team (circa 15), made up of passionate and like-minded Full stack JavaScript Engineers. As the Senior Engineering Manager you'll play a pivotal role in driving innovation, leading and ensuring the scalability of their product. You will play a key part in … level, whilst remaining close to the code and has a passion for this! What we expect from the Senior Engineering Manager: • 10+ years experience in software engineering - All things JavaScript, TypeScript + Java • 3+ years experience as an engineering manager - proven people/technical leadership experience. • Proven experience in system architecture design, including scalable, reliable and performant solutions. • Experience scaling More ❯

exploration with incredible savings. They are currently looking for a Senior Engineering Manager to lead their existing team (circa 15), made up of passionate and like-minded Full stack JavaScript Engineers. As the Senior Engineering Manager you'll play a pivotal role in driving innovation, leading and ensuring the scalability of their product. You will play a key part in … level, whilst remaining close to the code and has a passion for this! What we expect from the Senior Engineering Manager: • 10+ years experience in software engineering - All things JavaScript, TypeScript + Java • 3+ years experience as an engineering manager - proven people/technical leadership experience. • Proven experience in system architecture design, including scalable, reliable and performant solutions. • Experience scaling More ❯

exploration with incredible savings. They are currently looking for a Senior Engineering Manager to lead their existing team (circa 15), made up of passionate and like-minded Full stack JavaScript Engineers. As the Senior Engineering Manager you'll play a pivotal role in driving innovation, leading and ensuring the scalability of their product. You will play a key part in … level, whilst remaining close to the code and has a passion for this! What we expect from the Senior Engineering Manager: • 10+ years experience in software engineering - All things JavaScript, TypeScript + Java • 3+ years experience as an engineering manager - proven people/technical leadership experience. • Proven experience in system architecture design, including scalable, reliable and performant solutions. • Experience scaling More ❯

exploration with incredible savings. They are currently looking for a Senior Engineering Manager to lead their existing team (circa 15), made up of passionate and like-minded Full stack JavaScript Engineers. As the Senior Engineering Manager you'll play a pivotal role in driving innovation, leading and ensuring the scalability of their product. You will play a key part in … level, whilst remaining close to the code and has a passion for this! What we expect from the Senior Engineering Manager: • 10+ years experience in software engineering - All things JavaScript, TypeScript + Java • 3+ years experience as an engineering manager - proven people/technical leadership experience. • Proven experience in system architecture design, including scalable, reliable and performant solutions. • Experience scaling More ❯

facing and internal problems that drive value. Champion security, observability, and reliability best practices. Mentor teammates and help cultivate a healthy, innovative engineering culture. Tech Stack: Core: TypeScript/JavaScript (server-side) Cloud & Infra: AWS (cloud-based architectures), Docker, CI/CD; IaC such as Terraform or CloudFormation Quality & Ops: Security and observability tooling/best practices Bonus exposure: React … on the front end (nice to have) What we’re looking for We value skill and impact over strict year counts. You should have: Strong TypeScript/JavaScript fundamentals and experience building high-traffic server-side web applications. Solid understanding of cloud-based application architecture (preferably AWS). Hands-on experience with Docker and CI/CD tooling. Practical grasp More ❯

facing and internal problems that drive value. Champion security, observability, and reliability best practices. Mentor teammates and help cultivate a healthy, innovative engineering culture. Tech Stack: Core: TypeScript/JavaScript (server-side) Cloud & Infra: AWS (cloud-based architectures), Docker, CI/CD; IaC such as Terraform or CloudFormation Quality & Ops: Security and observability tooling/best practices Bonus exposure: React … on the front end (nice to have) What we’re looking for We value skill and impact over strict year counts. You should have: Strong TypeScript/JavaScript fundamentals and experience building high-traffic server-side web applications. Solid understanding of cloud-based application architecture (preferably AWS). Hands-on experience with Docker and CI/CD tooling. Practical grasp More ❯

facing and internal problems that drive value. Champion security, observability, and reliability best practices. Mentor teammates and help cultivate a healthy, innovative engineering culture. Tech Stack: Core: TypeScript/JavaScript (server-side) Cloud & Infra: AWS (cloud-based architectures), Docker, CI/CD; IaC such as Terraform or CloudFormation Quality & Ops: Security and observability tooling/best practices Bonus exposure: React … on the front end (nice to have) What we’re looking for We value skill and impact over strict year counts. You should have: Strong TypeScript/JavaScript fundamentals and experience building high-traffic server-side web applications. Solid understanding of cloud-based application architecture (preferably AWS). Hands-on experience with Docker and CI/CD tooling. Practical grasp More ❯