open-pdf-sign - Sign PDF files digitally from CLI or your webserver
PDFCrowd - Pdfcrowd is a Web/HTML to PDF online service. Convert HTML to PDF online in the browser or in your PHP, Python, Ruby, .NET, Java apps via the REST API.
TinyWow - TinyWow provides free online conversion, pdf, and other handy tools to help you solve problems of all types.
DocRaptor - As the only API powered by the Prince HTML-to-PDF engine, DocRaptor provides the best support for complex PDFs with powerful support for headers, page breaks, page numbers, flexbox, watermarks, accessible PDFs, and much more
Wondershare PDFelement - All-in-one PDF editor
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request