The declarative layout-based PDF library — pdfmake is an MIT-licensed engine (~12k+ GitHub stars) built on top of PDFKit where you describe a document as a JSON object (content array + styles + layout rules) and get a PDF, instead of imperatively drawing on a canvas. Ideal for structured documents like reports, invoices, tables, and multi-column layouts with automatic pagination and flow. Runs in browser and Node.js. No paid tier, no SaaS — the pick when you want to declare what the document looks like, not how to draw it.