LZ-String Decompress — Decode Compressed Strings Online
LZ-String Decompress turns an lz-string compressed value back into its original text. It automatically recognises every lz-string output variant — URL-safe (EncodedURIComponent), Base64, UTF-16, and raw — so you can paste a value from a shared link, localStorage, or an API and read the decoded result instantly. All decompression happens locally in your browser.
Every variant, detected automatically
The most common LZ-String frustration is a variant mismatch: a value produced by compressToBase64 will not decode with the EncodedURIComponent function, and vice versa. This tool removes the guesswork — it tries all four output variants (URL-safe, Base64, UTF-16, and raw) and returns whichever one yields valid text, so you can paste a compressed value from a URL, from localStorage, or from an API without knowing how it was created.
Because LZ-String's Base64 output is also valid plain Base64, SmartDevBox's auto-detection deliberately ranks this tool ahead of the generic Base64 Decoder for LZ-String payloads — plain Base64 decoding of a compressed value would just hand back binary garbage, whereas decompressing it recovers the original text.
How to read the result
A successful decompression returns the exact original string that was compressed — often JSON application state, a serialised document, or a block of text. If the value is not a valid LZ-String at all, you will see an error rather than a corrupted guess.
Everything runs locally in your browser; the compressed value and its decompressed contents are never sent to a server. To create compressed values, use the companion LZ-String Compress tool.
Common Use Cases
- Recovering app state encoded in a shared URL
- Inspecting lz-string compressed values from localStorage
- Decoding Base64-variant lz-string payloads from APIs or logs
- Debugging links that pack data via lz-string
Frequently Asked Questions
Which lz-string variants are supported?
All of them. The tool tries compressToEncodedURIComponent (URL-safe), compressToBase64, compressToUTF16, and plain compress, and returns whichever produces valid text — so you do not need to know how the value was compressed.
Privacy & Security
This tool runs entirely in your browser using client-side JavaScript. No data is sent to a server — your input never leaves your machine. SmartDevBox has no account system, no usage tracking, and no paid tier. See the Privacy & Security page for full details.
Related Tools
- LZ-String CompressCompress text with LZ-String into a URL-safe string in your browser. Free, no sign-up, 100% client-side.
- Base64 DecoderDecode any Base64 string back to plain text instantly in your browser. Free, no sign-up, 100% client-side. Supports standard and URL-safe Base64.
- URL DecoderDecode any percent-encoded URL string back to readable text instantly in your browser. Free, no sign-up, 100% client-side.