PDF to Structured JSON Without ML Training: A 2026 Developer Guide

PDF to Structured JSON Without ML Training Every team that ships a PDF processing feature reaches the same wall: OCR returns a string of words, but the user wants { "invoice_number": "INV-1234", "total": 4582.00, "line_items": [...] } . This is the gap LLMs solved in 2024-2025, and the patterns that actually work in production in 2026. The four eras of PDF extraction Text PDFs (1995-2010) — pdftotext gives you the text. Parsing structure is custom regex. Scanned PDFs (2010-2018) — Tesseract OCR.