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.
Apache PDFBox - The Apache PDFBox™ library is an open source Java tool for working with PDF documents.
PDFSwitch - Convert any HTML document or URL to PDF with a single API request.
PortableSigner - PortableSigner is a signing (with X.509 certificates) program for PDF files.
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
DocHub - Edit, send & sign PDFs online for free.