7 Free Format Conversion Tools Every Developer Needs in 2026

7 Free Format Conversion Tools Every Developer Needs in 2026 Every developer knows the pain. You're knee-deep in a project, and suddenly you need to convert a CSV into JSON. Then someone sends you GPX data from their GPS watch. Then your data scientist drops an Excel file full of nested objects and asks you to make it "web-ready." You could write a throwaway script for each one. Or you could use the right tool for the job and move on with your life. I've been curating ElysiaTools.com — a free, browser-based toolkit for developers — and today I want to walk you through the 7 format conversion tools I reach for most often. No signup. No rate limits. No "please upgrade." 1. CSV to JSON Converter Converting CSV to JSON sounds simple until you have 47 columns, some values with commas inside them, and a header row in a different language. This tool handles the edge cases: custom delimiters (comma, tab, semicolon, pipe), quote character handling, whitespace trimming, and the ability to skip e