Job Summary: Develop and maintain REST APIs, Windows Services, and Workers, implementing solutions based on SOLID design principles and scalable architectures to ensure code quality and efficiency. Key Highlights: 1. A leading company in secure payments and identification solutions 2. Daily innovation for over six decades 3. Operations in ID & Digital Government, Banking & Payments, and Secure Mobility Valid is a Powerhouse delivering Secure Payments, Identification Solutions, and Connectivity. We are one of the world’s largest producers of financial cards and the fifth-largest global supplier of SIM cards. For over six decades, we have innovated daily to empower each individual’s authenticity and simplify the lives of millions of people. **Responsibilities and Duties** **Responsibilities:** * Develop and maintain REST APIs, Windows Services, and Workers using **.NET 8.0** and .NET Framework 4.8. * Implement solutions based on SOLID design principles and scalable architectures. * Work with relational and NoSQL databases, ensuring integration and query optimization. * Develop interfaces using **React JS, JavaScript**, HTML5, and CSS3, ensuring a seamless user experience. * Integrate and implement authentication using OAuth, OpenID, and JWT. * Collaborate on development using GIT version control and messaging systems such as RabbitMQ or PubSub. * Ensure code quality and efficiency by applying best development practices. **Requirements and Qualifications** **Requirements:** * Solid experience with C#, .NET 8.0, and .NET Framework 4.8. * Advanced knowledge of JavaScript, HTML5, CSS3, and React JS. * Proficiency in developing REST APIs, Windows Services, and Workers. * Expertise in relational and NoSQL databases. * Knowledge of ORMs and messaging systems (RabbitMQ, PubSub). * Experience with OAuth, OpenID, and JWT. * Strong understanding of object-oriented programming principles and SOLID patterns. * Experience with GIT for version control. **Preferred Qualifications:** * Knowledge of software design patterns. * Experience with Docker and CI/CD pipelines. **But what exactly is Valid?** We are an integrator of secure identification solutions for people, journeys, and transactions—both physical and digital. Our solutions serve three major ecosystems: ID & Digital Government, Banking & Payments, and Secure Mobility. We are the leader in civil identification in Brazil, one of the world’s top producers of financial cards, and the fifth-largest global supplier of SIM cards for the mobile market. For over six decades, we have innovated daily to empower each individual’s authenticity and simplify the lives of millions of people. **We Are Driven by Big Challenges** We are not afraid to fail in pursuit of the best solutions to simplify life for our customers—and for our customers’ customers. Whenever a solution is complex, high-volume, and involves sensitive data, you can be certain Valid is behind it. Did you know Valid is already part of your daily life in this way? **Learn More About Our Operations** **Physical, digital, and “figital” identification documents for Brazilians go through Valid** We issue over 250 million documents—including the **RG** (Brazilian ID card) and the **CNH** (Brazilian driver’s license)—which are evolving into digital applications that, alongside their physical versions, are in the hands of thousands of Brazilian citizens. **The connectivity of millions of people worldwide goes through Valid** Nearly one billion mobile devices are connected to the internet via **SIM Cards** and **eSIMs** produced and orchestrated by Valid. **Transactions originating from multiple locations and devices go through Valid** Every day, more than 700 million transactions, payments, and inquiries are processed through Valid’s security solutions for credit cards, invoices, and statements.