Project 45, Hardware and performance

Browser File Compressor

Drop a file to gzip it, or drop a .gz file to unpack it. The browser's own compression streams do the work, so big files never get fully loaded into memory.

Main API: CompressionStream
Formats: gzip, deflate, deflate-raw
Dependencies: None
Your browser: Checking

Compress or decompress

Drop any file to compress it, or a .gz file to unpack it.

Waiting for a file

Or try with text

Result

Sizes appear here.

Before

After

Photos, videos and zip files are already compressed, so gzip saves little on them. Text, CSV, JSON and code shrink a lot.

How it works

Stream the filefile.stream() gives a ReadableStream, so the file is read piece by piece instead of all at once.
Pipe through gzippipeThrough(new CompressionStream("gzip")) compresses each piece as it passes. A small TransformStream counts bytes for the progress bar.
Collectnew Response(stream).blob() gathers the output into a file you can download.

async function gzip(file, onProgress) {
  let done = 0;
  const counter = new TransformStream({
    transform(chunk, ctl) { done += chunk.byteLength; onProgress(done / file.size); ctl.enqueue(chunk); },
  });
  const stream = file.stream()
    .pipeThrough(counter)
    .pipeThrough(new CompressionStream("gzip"));
  return new Response(stream).blob();                  // collect the output
}
// Unpack: file.stream().pipeThrough(new DecompressionStream("gzip"))