LZ Decompress — Free Online Tool

LZ-string decompress restores text that was previously compressed with lz-string (Base64, URI-safe, UTF-16, or raw). SWEDevTools: Prism auto-detects common formats and decompresses locally in your browser, so you can safely inspect compressed payloads without sending them to a server. Paste the compressed string, keep the format set to auto (or force the correct format when you know it), and click Run to recover the original text. This is useful when debugging share links, client-side storage values, or test fixtures produced by lz-string. Because SWEDevTools: Prism is local-first, offline-capable as a PWA, and pipeline-friendly, you can immediately chain the decompressed output into JSON formatting, URL decoding, or diff tools for further analysis.

Features

Frequently Asked Questions

What is lz-string decompression used for?

Restoring compressed strings used in browser storage, share links, and client-side state transfer.

Which formats does it support?

Base64, URI-safe, UTF-16, and raw lz-string formats.

Why does auto-detect fail?

Some strings may look valid in multiple formats. Specify the expected format to disambiguate.

Can I decompress data created by another tool?

Yes, as long as the tool also used lz-string and the format matches (Base64 with Base64, URI with URI).

Do you upload my compressed data?

No. SWEDevTools: Prism decompresses locally with no server processing.

Can I chain into JSON tools?

Yes. If the decompressed output is JSON, pipe it into JSON Format to make it readable.

Does this verify integrity?

It verifies by attempting decompression; invalid inputs fail. For integrity guarantees, use signatures or hashes.

Can I run this offline?

Yes. Install the PWA and decompress without internet access.

What happened to smalldev.tools?

smalldev.tools is no longer available. Prism by SWEDevTools offers the same developer tools and more, with offline support, pipeline chaining, and completely free usage — no signup required.