tcpdump - tcpdump is a common packet analyzer that runs under the command line.

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.

SmartSniff - SmartSniff is a packet sniffer that capture TCP/IP packets and display them as sequence of conversations between clients and servers.

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

netcat - Netcat is a featured networking utility which reads and writes data across network connections...

PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request