I built a 100% client-side File Converter in React & WebAssembly (Zero Cloud Uploads)

Every time I needed to convert an iPhone .HEIC photo, merge PDFs, or convert a CSV to Excel, online tools forced me to upload private files to their cloud servers and hit me with a "Max 3 files per day" paywall.

With modern browser APIs, uploading files to a backend server just to convert formats isn't necessary anymore. So I built ZeroConvert:

🔗 Live Tool: https://getzeroconvert.com

How It Works Under the Hood

• Images (HEIC, WebP, AVIF, PNG, JPG): Processed locally using HTML5 Canvas and client-side decoding buffers.
• Documents & PDFs: Merged and converted in local RAM via pdf-lib and pdfjs-dist.
• Spreadsheets & Data (XLSX, CSV, JSON, XML): Parsed instantaneously in the browser using SheetJS.
• Audio & Video (MP4, MP3, WAV, WebM): Powered by FFmpeg.wasm running inside Web Workers.

Because there are zero server uploads, conversions happen at native memory speed with 100% privacy and zero daily caps.

Would love for you to test it out and let me know what formats or features I should add next!