About 123FileConverter
123FileConverter is a free online file converter built around a simple idea: your files should stay yours. Wherever the browser is capable, conversions run locally on your own device — instantly, with no upload and no size limit.
How it works
Modern browsers can do a surprising amount. We use the Canvas API to convert images, plain JavaScript to transform text and data formats, native compression streams to repack archives, and WebAssembly (ffmpeg.wasm) to transcode audio and video — all client-side.
When a format genuinely needs heavy tooling (office documents, ebooks), we fall back to a secure server pipeline that deletes your files automatically after conversion.
Why it’s different
- Privacy by default — most conversions never touch a server.
- No accounts, no watermarks, no nagging.
- Minimal server load, which keeps the service fast and free.