Role Description We're looking for Mid-Level and Senior Front-end Engineers to join a fully remote team. This opportunity is open to candidates based in the European Union. You'll work on modern, large-scale web applications using a cutting-edge frontend ecosystem and micro-frontend architecture. As part of a collaborative engineering team, you'll help build scalable, high-performance solutions while contributing to the evolution of modern development practices and user experiences. What You Will Be Doing - Develop and maintain modern frontend applications using React 19 and TypeScript (strict mode). - Build scalable micro-frontends using Module Federation. - Implement routing with TanStack Router. - Collaborate within a Turbo monorepo powered by Node.js 24 and pnpm workspaces. - Build and maintain reusable UI components using Tailwind CSS, a shared Design System, and Storybook. - Create type-safe APIs and validation using Zod. - Write unit and integration tests with Vitest. - Develop end-to-end, accessibility, and visual regression tests using Playwright. - Contribute to backend utilities and platform services with Fastify when needed. - Ensure code quality using Biome for linting and formatting. - Support application observability through OpenTelemetry and Prometheus. Qualifications - Mid-level or Senior experience as a Front-end Engineer. - Strong proficiency in TypeScript, including strict mode. - Solid commercial experience with React. - Experience building scalable frontend applications and component-based architectures. - Familiarity with modern build tools such as Rsbuild/Rspack or similar bundlers. - Experience with testing frameworks such as Vitest and Playwright. - Understanding of modern CSS practices and experience with Tailwind CSS. - Experience working with Git and collaborative development workflows. - Strong problem-solving and communication skills. - EU citizenship or legal authorization to work remotely within the European Union. Requirements - Experience with Module Federation and micro-frontend architectures (nice to have). - Experience with Fastify (nice to have). - Familiarity with Storybook, Zod, OpenTelemetry, and Prometheus (nice to have). - Experience working in monorepos using Turbo and pnpm workspaces (nice to have). Benefits - Salary ranges (for employees in Lithuania only): from 4500 € gross (it is flexible and depends on your experience). - Personalized benefits packages that cater to your unique passions. - Top Talent Collaboration: Join award-winning teams from different countries. - Diverse, Challenging Projects: Break free from the ordinary with dynamic, stimulating work. - Epic Team Events: Join us for summer and winter parties and online events. - Learning & Development Opportunities: That new tech certificate is just around the corner. - Special Celebrations: We love a good shindig for birthdays and project milestones.

Our Purpose Mastercard powers economies and empowers people in 200+ countries and territories worldwide. Together with our customers, we're helping build a sustainable economy where everyone can prosper. We support a wide range of digital payments choices, making transactions secure, simple, smart and accessible. Our technology and innovation, partnerships and networks combine to deliver a unique set of products and services that help people, businesses and governments realize their greatest potential. Title and Summary Lead Software Engineer Overview Be part of the Operations & Technology Fraud Products team developing new capabilities for MasterCard's Decision Management Platform, which serves as the core for multiple business solutions to combat fraud and validate cardholder identity. Our patented Java-based platform processes billions of transactions per month in tens of milliseconds using a multi-tiered, message-oriented approach for high performance and availability.• Would you like to develop industry leading solutions for fighting fraud?• Are you motivated by speeding business solutions to market?• Do you want to innovate, using cutting edge technologies on challenging business problems? Role This role involves working with a team of talented developers to develop high performance, high volume solutions. You will be responsible for:• Lead day to day systems development and maintenance activities of the team to meet service level agreements (SLAs) and create solutions with high level of innovation, cost effectiveness, high quality and faster time to market.• Accountable for full systems development life cycle including creating high quality requirements documents, use-cases, design and other technical artifacts including but not limited to detailed test strategy/test design, performance benchmarking, release rollout and deployment plans, contingency/back-out plans, feasibility study, cost and time analysis and detailed estimates.• Collaborate with Architects, fellow Leads, Developers, Business Analysts & Product Owners in Dublin & other Mastercard locations.• Develop high-quality, secure, scalable and maintainable Java-based software solutions. • Apply best practices for automated testing, automated code quality, automated delivery & automated monitoring.• Mentor the senior & junior engineers on your team through sound technical advice, UML documentation & code reviews.• Assist with troubleshooting production incidents & channel learnings back into the development stream to mitigate future customer impact.• Participate in PoCs (Proof of Concept) and help the Department with selection of Vendor Solutions, Technologies, Methodologies and Frameworks.• Collaborate with vendor resources for support of products.• Conduct brownbag sessions on new and upcoming technologies, methodologies and application appropriate frameworks.• Actively look for opportunities to enhance standards and improve process efficiency.• Perform Quality Inspections and Walkthroughs throughout the SDLC including Requirements Review, Design Review, Code Review and Security Review to ensure compliance with Mastercard and PCI standards.• Work as part of a co-located Agile SCRUM team. All About You• Must be high-energy, detail-oriented, proactive and have the ability to function under pressure in an independent environment. • Must provide the necessary skills to have a high degree of initiative and self-motivation to drive results. • Possesses strong communication skills -- both verbal and written - and strong relationship, collaborative skills and organizational skills. • Willingness and ability to learn and take on challenging opportunities and to work as a member of matrix based diverse and geographically distributed project team.• Deep knowledge of software development processes including agile processes and test driven development.• Experience with the design and development of complex, multi-tier software solutions.• Essential Skills required:• A wide breadth and depth of technical experience using Java/JEE• Strong Linux and shell scripting• Oracle & PL/SQL and advanced SQL scripting• Extreme Performance or NoSQL Data Storage such as GemFire Object Grid, Terracotta, or Cassandra• Spring Framework (including Spring Boot)• J2EE Web Application/Web Services (e.g. with JBoss and/or Apache Tomcat)• Web Services - REST/XML/JSON• Desirable Skills:• Messaging - MQ and JMS• Business rules execution systems (e.g. IBM Operational Decision Manager (ODM - formerly ILOG) or JBoss Drools)• Experience integrating vendor and open source products into an overall system• Experience working with containerised environments, such as Kubernetes/OpenShift/CloudFoundry• Experience with integration frameworks such as Apache Camel/Spring Integration• Experience with monitoring service performance Experience with visual design tools (Visio, Confluence Gliffy, etc.) Corporate Security Responsibility All activities involving access to Mastercard assets, information, and networks comes with an inherent risk to the organization and, therefore, it is expected that every person working for, or on behalf of, Mastercard is responsible for information security and must: - Abide by Mastercard's security policies and practices; - Ensure the confidentiality and integrity of the information being accessed; - Report any suspected information security violation or breach, and - Complete all periodic mandatory security trainings in accordance with Mastercard's guidelines.

Job Description At Citadel, our engineers work in small teams to turn the best ideas into high-performing and resilient technology. With short development cycles, work rapidly goes into production. As an engineer, you can create system architectures, develop platforms and build web frameworks. You'll have access to state-of-the-art tools and apply innovative techniques including distributed computing, natural language processing, machine learning and more. As an intern, you'll get to challenge the impossible in technology through a summer program that will allow you to collaborate and connect with senior team members. In addition, you'll get the opportunity to network and socialize with peers throughout the internship. Your Objectives: - Create technological tools that bring trading strategies to life - Develop high-performance, large data research platforms - Work in small teams to build the future of finance Your Skills & Talents: - Bachelor's, master's or PhD in computer science, computer engineering or related fields - Exceptional programming and design skills - Strong analytical skills and familiarity with probability and statistics - Ability to communicate effectively in a collaborative, complex and highly technical team environment - Intellectual curiosity and passion for solving challenging problems using technology Opportunities may be available from time to time in any location in which the business is based for suitable candidates. If you are interested in a career with Citadel, please share your details and we will contact you if there is a vacancy available. We collect and use personal data in accordance with our Privacy Policy. We retain data on prospective candidates and may consider suitability for alternative opportunities at Citadel. For more information, see our Privacy Policy. About Citadel Citadel is one of the world's leading alternative investment managers. We manage capital on behalf of many of the world's preeminent private, public and nonprofit institutions. We seek the highest and best use of investor capital in order to deliver market leading results and contribute to broader economic growth. For over 30 years, Citadel has cultivated a culture of learning and collaboration among some of the most talented and accomplished investment professionals, researchers and engineers in the world. Our colleagues are empowered to test their ideas and develop commercial solutions that accelerate their growth and drive real impact.

Role Description Join the team as Twilio’s next Senior Software Engineer. This position will be part of a team of talented engineers within our Commerce Platform Team, who build services and products that operate at a massive scale. This platform is central to Twilio's core business as it is responsible for managing the billing lifecycle and payment experience for our customers, while also acting as a gateway for discovering and selling our products. Billing is going through a transformational journey, and we are introducing new and exciting capabilities. The engineer in this role will be part of a team that focuses on the control plane, billing experience and account lifecycle management. The successful candidate will design, build, and operate core billing platform services that help transition our platform and our customers to the next generation architecture. These services work for all Twilio customers, regardless of their scale and billing complexity. The ideal candidate will build high-quality, innovative and fully performing software that complies with high levels of coding standards and technical design. This is to build and integrate services that continuously improve our ability to provide products to customers while simultaneously delivering industry leading availability. We do this by leveraging technologies that include AWS cloud infrastructure and APIs, Apache Kafka, Rest APIs (OpenAPI compliance), while also building our own services. Responsibilities - Improve your knowledge of highly available and scalable distributed systems and use this knowledge to build new features into our platform. - Design, implement, and operate both new features on our current services as well as new services that will be built from scratch. - Leverage your excellent communication and written skills to articulate the "why" of the solution you are proposing, and have a good understanding of your team’s priorities and the customer impact. - Troubleshoot and fix operational issues and have the opportunity to improve the troubleshooting procedures and tools. - Execute full software development life cycle (SDLC). - Develop flowcharts and documentation to identify solutions. - Write well-designed, testable code. - Document and maintain software functionality. - Troubleshoot, debug and upgrade existing systems. Qualifications - 5+ years of work experience building highly scalable products. - 5+ years of programming experience in object-oriented language (Java or similar) with clean code practices. - Expert knowledge in Object-Oriented Programming with a successful track record. - Experience contributing to architecture and design (architecture, design patterns, reliability and scaling) of new and current systems. - Experience working closely with our Product team to understand requirements and help to define technical work for the team. - Experience working with stakeholders at all levels - be able to dive into the nuts-and-bolts of how things work as needed. - Experience with relational and non-relational databases. - Experience delivering high levels of observability and proficiency in improving early warning systems, for example: has worked with Grafana/DataDog/Prometheus. - Collaborating with internal/external teams/engineers and fostering an inclusive environment, where all points of view are welcomed and encouraged. - Own and lead multiple domains of the platform (microservices, REST APIs, infrastructure) from inception to deployment and maintenance, while making best in class technical decisions that impact the success of the company. - Familiarity in Cloud Solutions, AWS, Kubernetes/EKS, CI/CD pipelines, Testing & Automation. - Self driven - you take complete ownership of your tasks and champion efforts to get your tasks to completion. - Clear written and spoken communication skills. - Degree in Computer Science or a related field, or equivalent work experience. Requirements - Experience with on-call support for mission-critical customer systems. - Experience optimizing and debugging complex SQL queries. - Experience working on customer-facing applications. - Good debugging skills on production systems. - Proficient in Linux and containerization with Kubernetes. - Nice to have skills: gRPC, Python, Typescript, React, Apache Kafka. Location This role will be remote, and based in Ireland. Travel We prioritize connection and opportunities to build relationships with our customers and each other. For this role, you may be required to travel occasionally to participate in project or team in-person meetings. Benefits - Competitive pay. - Generous time off. - Ample parental and wellness leave. - Healthcare. - A retirement savings program. - And much more. Offerings vary by location.