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.
Inkly - send real printed cards with your own handwriting inside
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
NanaGram - Text your photos and we'll mail 4x6 prints to your Nana.
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
Skip The Stamps - Snap or upload a pic to send a physical postcard in minutes