I Built a File Converter That Handles 16 Formats in the Browser — No Upload Required

A client once sent me a PDF invoice and asked for it as a CSV. Then sent a HEIC photo that needed to be PNG. Then an XML config that needed JSON. Three different tools, three different uploads, three different privacy policies to read.

I got fed up and built one tool that handles all of it locally.

The Stack

The core is surprisingly simple. Each conversion is an "engine" — a small JavaScript module that takes input and returns output:

PDF to JPG: Canvas-based page rendering + per-page export