PolyDoc

HTML/URL to PDF and screenshots, plus Factur-X/ZUGFeRD e-invoices; free tier

Official docs outline

Extra Credit builds an outline of PolyDoc's docs the first time your work uses it. Until then, start at the official documentation.

PandaDoc DocGen and eSignatures API
PDFFleet HTML and URL to PDF API with templates and a free tier
PDFMint HTML, Markdown or a URL to PDF or PNG, with a no-key demo endpoint and a free tier
pdfrender HTML and CSS to PDF with page headers, footers and page numbers, no headless browser
Pocket Bookmarking service
Podio File sharing and productivity
PrexView Data from XML or JSON to PDF, HTML or Image
PrintSocket Send PDFs, ZPL labels and ESC/POS receipts to your own printers from any language; free tier
Renderly HTML to PDF conversion API built on Chromium
Rendex Render HTML, Markdown, or URLs to PNG/JPEG/WebP/PDF, with extraction and templating
Restpack Provides screenshot, HTML to PDF and content extraction APIs
RunConvert Convert video, audio, image, and document files programmatically