PDFCrowd - Pdfcrowd is a Web/HTML to PDF online service. Convert HTML to PDF online in the browser or in your PHP, Python, Ruby, .NET, Java apps via the REST API.
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
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.
Document Cyborg - Easily save a web page as a document (PDF, WORD, EPUB, ODT, RTF or Text)
Api2Pdf - PDF Generation API, powered by AWS Lambda. HTML to PDF | URL to PDF | Office Doc to PDF | Merge PDFs . Supports wkhtmltopdf, Headless Chrome, and LibreOffice. No rate limits and no file size limits.