PDF Joiner - This online tool allows you to join several PDF documents into a single file, free of charge.
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
PDFChef Merge PDF - PDFChef Merge PDF is an online tool that allows you to merge multiple PDf files into one quickly and securely.
HTML PDF API - Easily generate PDF documents from HTML code with our powerful API
PDFill - Open, View, Edit, Save and Print PDF Documents without Adobe Acrobat
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.