LZ-String Compressor
Compression · Free Online Tool
lz-string compress/decompress for short text in URLs/LocalStorage.
Click "Compress" to run...Pure JavaScript
Runs entirely in JS — works in any browser, even old ones without CompressionStream.
Great for Storage
Ideal for stuffing large JSON into localStorage, cookies, or short URLs.
Base64 Output
Output is safe to embed in JSON, URLs, and text fields.
How to Use LZ-String 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.
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Learn the concept
Learn the concept
Understand the programming ideas behind this tool.