HTML PDF API - Easily generate PDF documents from HTML code with our powerful API
pdflayer - Free, powerful HTML to PDF API supporting both URL and raw HTML conversion. Unlimited document size, lightning-fast and compatible PHP, Python, Ruby, etc.
Tcpdf - TCPDF: Open Source PHP Class for generating PDF documents
HTML2PDF.fr - HTML2PDF is a HTML to PDF converter that allows the conversion of valid HTML 4.
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
PDF-LIB - Create and modify PDF documents in any JavaScript environment