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
DeftPDF - An all-in-one free online PDF editor that does not require subscriptions or installations! DeftPDF is a free online tool that makes editing and converting easy in just a few clicks!
Anvil PDF Filling API - The easiest way to programmatically populate any PDF
Jotform PDF Editor - Automatically create polished, designed documents
PlutoPDF - A URL to PDF converter wrapped behind a simple API.