PDFMate Free PDF Merger - PDFMate Free PDF Merger works as a PDF Joiner, PDF combiner, PDF breaker, image to PDF converter and PDF encryptor. With PDF Merger, you can batch merging pdf files, combining specified pages or converting scanned image file to create new PDF file.
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
PDF Joiner - This online tool allows you to join several PDF documents into a single file, free of charge.
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
DocuPUB - DocuPUB is an online file converter, file merger, file compressor, and file resizing tool.
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.