Summary: Sinch is seeking a Software Engineer to develop and maintain their Node.js SDK and contribute to SDK generation tooling, focusing on developer experience and API consumption. Highlights: 1. Key role in how Sinch APIs are consumed across multiple programming languages 2. Primary developer for a modern, user-friendly TypeScript SDK 3. Core contributor to SDK generation tooling for various languages **About Sinch** Sinch is pioneering the way the world communicates. More than 150,000 businesses — including Google, Uber, PayPal, Visa, Tinder, and many others — rely on Sinch’s Customer Communications Cloud to power engaging customer experiences through mobile messaging, voice, and email. Whether you need to verify users or craft omnichannel campaigns, Sinch makes it easy. Our AI\-infused Super Network, APIs, and applications ensure you can connect with your customers reliably and securely, at every step of their journey. At Sinch we “Dream Big”, “Win Together”, “Keep it simple”, and “Make it Happen”. These values are our foundation! **About the role** As a Software Engineer in our **Developer Experience (DX)** organization, you will play a key role in how Sinch APIs are consumed across multiple programming languages. Your primary focus will be the **development and maintenance of Sinch’s Node.js SDK** , one of our most widely used SDKs. Through this work, you will gain deep familiarity with Sinch APIs, products, and developer expectations. In addition, you will be a core contributor to our **SDK generation tooling** , which is used to generate Java, Node.js, Python, and .NET SDKs from OpenAPI specifications. In this role, you will help scale SDK development across languages by implementing shared generation logic, templates, and conventions that other members in the SDK team rely on. This is a developer\-facing platform role with strong impact across the entire DX organization. This role is open to candidates based in **Spain** , from our offices in **Madrid** . **What you will do** As a Software Engineer, you will: * Be the primary developer on the SDK/library you are responsible for, through the whole development cycle: design, develop, and maintain a **modern, user\-friendly TypeScript SDK** . * Work closely with your Developer Experience colleagues on SDK features and overall SDK consistency. * Ensure the SDK is **well\-documented, easy to use, and follows best practices** for TypeScript and Node.js development. * Write clean, efficient, and maintainable **TypeScript** code, with a strong focus on developer experience. * Implement robust error handling, logging, and testing to ensure reliability. * Optimize SDK performance and usability, gathering feedback from internal and external developers. * Work with the documentation team to keep all documentation easy to read, test, and enriched with relevant examples. * Stay up to date with the latest **Node.js, TypeScript, and ecosystem** features and industry trends. **Requirements** * 5\+ years of professional experience in **TypeScript and Node.js development** . * Strong understanding of **REST API design and consumption** . * Experience with **npm package creation, versioning, and maintenance** . * Knowledge of **CI/CD pipelines** and release workflows. * Familiarity with asynchronous programming patterns in JavaScript/TypeScript. * Comfort working in a role where **developer experience,** usability and API design quality are key success metrics. Fluent English, both written and spoken. * **Nice to have** * Experience in **SDK or library development** is a strong plus. * Familiarity with modern TypeScript features and tooling. * Knowledge of **OpenAPI specifications** and API schema\-driven development. * Knowledge of **Python** or **.NET** is an added value (to review other SDKs code). * Knowledge of **Java** and interest in expanding your skills in this area is very welcome. * Excellent problem\-solving skills and attention to detail. * Ability to communicate clearly in both **user documentation and code** . **Our Hiring Process** We are committed to ensuring a recruitment process that is fair, objective, consistent, and inclusive. Our approach includes structured, competency\-based interviews designed to evaluate your skills, experience, and qualifications relevant to the role. At times, we may include a data\-driven assessment to enhance our hiring success and identify candidates likely to excel. We believe in a two\-way process and encourage you to ask questions throughout the journey. If this role isn't what you're looking for, please explore the other opportunities listed on our career page: https://www.sinch.com/careers/ . No matter who you are, we hope you find an exciting path forward \- hopefully with us! **Please send your CV in English language.**