PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
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
Tcpdf - TCPDF: Open Source PHP Class for generating PDF documents
CloudConvert - convert anything to anything - more than 200 different audio, video, document, ebook, archive, image, spreadsheet and presentation formats supported.
HTML PDF API - Easily generate PDF documents from HTML code with our powerful API
wkhtmltopdf - wkhtmltopdf is an open source (LGPL) command line tools to render HTML into PDF and various image...