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.
HTMLEmail.io - Responsive HTML email templates for startups & developers
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
Startup Emails - Responsive HTML email templates for startups
Tcpdf - TCPDF: Open Source PHP Class for generating PDF documents
Stripo - Stripo is an all-in-one email design platform. We enable our clients to build emails of any complexity, including interactive AMP emails, really fast and easy.