html2pdf.app - HTML to PDF conversion 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.
Usetiful - Fight user churn with great user onboarding. Interactive product tours and smart tips significantly improve your user retention.
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request