Back to feed
Dev.to
Dev.to
7/3/2026
I Built a Free Browser-Based File Converter Using WebAssembly — No Uploads, Ever

I Built a Free Browser-Based File Converter Using WebAssembly — No Uploads, Ever

Short summary

Developer built utilize.internet, a privacy-first browser-based file converter using WebAssembly (ffmpeg.wasm for video, pdf-lib for PDFs). All processing happens client-side—files never leave your device. Post details implementation patterns: CORS workarounds for Web Workers, multi-pass FFmpeg filtering for GIF quality, and a lightweight inline ZIP writer.

  • •Built browser-based file converter (video→GIF, PDF merge, etc.) using WebAssembly—100% client-side, zero server uploads
  • •All processing via browser APIs: ffmpeg.wasm, pdf-lib, Canvas—no user files stored anywhere
  • •Shared technical patterns: CORS self-hosting fix for workers, palettegen optimization for GIF colors, minimal ZIP writer without external libs

Generated with AI, which can make mistakes.

#ai-tools#product-launch#open-source
Read full article at Dev.to

Is this a good recommendation for you?

Comments

Failed to load comments. Please try again.

Explore more

I built 50+ free browser tools that run without uploads, servers, or accounts
Dev.to
Why We Built a Browser-Based File Converter Instead of Another Cloud Service
Dev.to
I Built a File Converter That Handles 16 Formats in the Browser — No Upload Required
Dev.to
I Built 58 Free Browser Tools With Zero Backend — Here's the Full Stack
Dev.to