To follow on with this, I've used https://pdfcrowd.com/ too. - Source: Reddit / about 2 months ago
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
Document Cyborg - Easily save a web page as a document (PDF, WORD, EPUB, ODT, RTF or Text)
Tcpdf - TCPDF: Open Source PHP Class for generating PDF documents
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.
DocRaptor - Forget tedious coding or server management: Our simple API that makes it easy to convert HTML to PDF, XLS and Excel files.
PDF my URL - PDFmyURL turns any webpage or even complete website into PDF. Use our rest API in PHP, .NET, Ruby, Perl or any other programming language. Or convert webpages or even full websites directly in the browser!