Punchbowl - A party planning and greeting card website
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
Whoozin.com - Free RSVP Online | Track RSVP’s and Sell Tickets for your events and recurring meetings.
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
JustRSVP.me - Online Invitations and response tracking for weddings, baby showers, birthdays, parties, and other...
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.