The original low-level PDF-generation engine for Node.js — PDFKit is a mature MIT-licensed library (since 2012, ~9k+ GitHub stars) for generating PDFs programmatically from scratch: vector graphics, text with embedded TrueType/OpenType fonts, images, gradients, annotations, and links. It is the foundation that higher-level libraries like pdfmake build on top of. Originally Node.js-focused (uses some Node APIs) with browser builds available via bundlers. No paid tier, no SaaS — the low-level primitives for full control over PDF layout.