Jotform PDF Editor - Automatically create polished, designed documents
Anvil PDF Filling API - The easiest way to programmatically populate any PDF
PlatoForms - Convert PDFs to forms and let people fill them easily.
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
PlutoPDF - A URL to PDF converter wrapped behind a simple API.
PDFify - PDF creation with text recognition and scanner support. Features email and webpage import to PDF.