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Zlib Compressor

Compression · Free Online Tool

Zlib format (RFC 1950) compress and decompress.

By EZ4Code TeamLast updated: 2026-10-29

Browsers map 'deflate' to the zlib format (RFC 1950). If you need raw deflate (no header), use the Deflate-Raw tool.

Input Text235 chars

Compressed (Base64)

0 chars

Click "Compress" to run...

RFC 1950 Framing

Produces a 2-byte zlib header (CMF/FLG) and an Adler-32 checksum trailer around the deflate stream.

Native & Fast

Backed by the browser's built-in CompressionStream — no third-party libraries needed.

Base64 Transport

Output is base64-encoded for safe copy/paste between systems.

How to Use Zlib Compressor

1Enter or paste the text you want to compress.
2Select the compression algorithm (gzip, deflate, or brotli).
3Click compress to reduce the data size.
4Copy or download the compressed output.

Features

✓100% free — no signup, no subscription, no ads
✓Runs entirely in your browser — data never leaves your device
✓Fast and lightweight — instant results
✓Cross-platform — works on desktop, tablet, and mobile

Frequently Asked Questions

What compression algorithms are supported?

We support gzip, deflate, and brotli compression algorithms for text data.

Is there a file size limit?

Since tools run in your browser, the limit depends on your device memory. Most tools handle several megabytes without issues.

Can I decompress data produced by other software?

Yes. The decompression tools accept standard gzip, deflate, and brotli streams from any compliant source — command-line tools, web servers, or other libraries.

Why does the compressed output look unreadable?

Compressed data is binary, not text. Use Copy as Base64 or download it as a file — pasting raw compressed bytes into a text field will show garbled characters.