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.
Cyclr - Powerful SaaS integration toolkit for SaaS developers - create, amplify, manage and publish native integrations from within your app with Cyclr's flexible Embedded iPaaS.
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request