Anvil PDF Filling API - The easiest way to programmatically populate any PDF
PDFify - PDF creation with text recognition and scanner support. Features email and webpage import to PDF.
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
KDAN Mobile PDF Reader - PDF Reader is the one app you can rely on when you need a portable solution to work with PDFs.
PlutoPDF - A URL to PDF converter wrapped behind a simple API.
Jotform PDF Editor - Automatically create polished, designed documents