Gzip/Deflate ↔ Base64

Base64 by itself doesn't compress anything — quite the opposite, it grows the size by about 33%. To send large text compactly through a text-only channel, it's first compressed with Gzip or Deflate, and only then is the result Base64-encoded.

How to use it

• Compress: paste text and the tool compresses it with Gzip or Deflate (the browser's Compression Streams API) and encodes the result as Base64.
• Decompress: paste a Base64 string of compressed content to get the original text back.
• Pick Gzip or Deflate depending on which format the receiving system expects.

Common uses

• Compactly embedding a large text value (an SVG, a config) in a URL parameter or cookie with a size limit.
• Preparing a compressed payload for an API that accepts Base64-encoded Gzip data.
• Decompressing data received in this format from another system so it can be read manually.

Things to keep in mind

Compression only pays off on sufficiently large, compressible text — on short strings the Gzip header overhead plus the Base64 expansion can actually make the result bigger.

Deflate skips Gzip's headers, so its output is more compact, but the format is less self-describing: the receiving side needs to know in advance that it's Deflate specifically.