Yes, C9 provides ongoing support and maintenance services for ReactJS projects. After the initial development phase, C9's team of ReactJS experts can continue to monitor, maintain, and update the application as needed. This includes addressing any bugs or issues, implementing new features or functionality, and ensuring the application remains up-to-date with the latest ReactJS technologies and security patches. C9 can tailor the support and maintenance plan to the client's specific needs and requirements, ensuring the continued success and performance of the ReactJS application.