Instead of saving to disk, send call variables directly to a Node.js/Go microservice that streams back a PDF:
<action application="curl" data="https://pdf-api.company.com/generate?caller=$caller_id_number&duration=$duration POST"/>
If you prefer a structured book format (PDF), the industry-standard books are published by Packt Publishing: freeswitch 18 pdf hot
The most overlooked feature in the 1.8 ecosystem is the ability to ingest PDFs. Using mod_curl combined with a local Tesseract OCR engine, a 1.8 server can: Instead of saving to disk, send call variables
This turns a VoIP switch into an automated accounts payable clerk. If you prefer a structured book format (PDF),
You might ask: Why not 1.10?
The answer is Performance Predictability. FreeSWITCH 1.8 lacks the memory overhead of newer STUN/TURN servers and graph databases. It runs beautifully on a 1GB VM. When processing PDFs (which are memory-heavy), the 1.8 memory allocator is more aggressive, leading to lower "GC" pauses.
The "Hot" Benchmark: In stress tests, a single FreeSWITCH 1.8 instance handling PDF-to-Fax conversion sustained 2,400 concurrent sessions with an average latency of 450ms for PDF generation. Newer versions, with more safety checks, cap out around 1,800 for the same hardware.