PDF Reactor is a component for web applications converting HTML to PDF.
PDFreactor is a printing component for web applications. It is typically used for server-side conversion of HTML to PDF, ranging from dynamic data-driven documents (reports, invoices, forms, data sheets) for electronic distribution to complex and high-quality PDFs (catalogs, marketing collateral, technical documentation, journals) for print and electronic publishing.
More details can be found on the official website and in the official manual (PDF) (HTML).