Do you enjoy building scalable backend systems that power seamless digital experiences? Do you thrive in integration-heavy environments where performance, data flow, and reliability matter? Do you like working behind the scenes to ensure platforms talk to each other efficiently and securely? As a C# / .NET Developer, you will play a key role in expanding and supporting a client's middleware layer that integrates Shopify and other systems. You may also contribute to a mobile app backend running in a Platform-as-a-Service (PaaS) environment, as the existing provider transitions off the account. This role requires strong backend engineering skills, experience with APIs and integrations, and the ability to work independently in a fast-paced environment. Responsibilities • Design, develop, and maintain middleware applications using C# and .NET. • Build and maintain integrations between Shopify and external systems. • Use GraphQL to query and manipulate data from Shopify APIs. • Enhance and support existing middleware services currently in production. • Collaborate with cross-functional teams to define, design, and implement scalable solutions. • Support and potentially transition ownership of a mobile app backend (PaaS-based). • Optimize application performance, scalability, and reliability. • Troubleshoot and resolve complex backend and integration issues. • Write clean, maintainable, and well-documented code. • Participate in code reviews and follow engineering best practices. Requirements • Experience: Minimum of 4-5 years of hands-on experience with C# and .NET development. • Backend Development: Strong experience building APIs, services, and middleware architectures. • Shopify (Preferred): Experience working with Shopify APIs. Direct Shopify development experience is ideal. • GraphQL: Solid experience using GraphQL to query and manipulate data (Shopify GraphQL Admin API experience is a plus). • Cloud / PaaS: Experience working in cloud-based or PaaS environments. • Integration Experience: Proven experience integrating third-party systems and APIs. • Problem-Solving: Strong analytical and troubleshooting skills with the ability to resolve complex backend issues. • Communication: Strong written and verbal communication skills. Ability to work effectively with client stakeholders and distributed teams. • Collaboration: Experience working in an agile development environment. Remote Work • This position qualifies for remote work anywhere in the United States.