Compress text to a Base64 or URL-safe string, or paste a compressed blob and get the text back — all in your browser.
Paste your text, pick an algorithm and an output encoding, and click Compress. To reverse it, paste any compressed Base64 (or URL-safe) string into Decompress — the tool sniffs gzip, zlib, raw deflate and LZ-string automatically. Compression uses the browser's native CompressionStream, so it matches what gzip produces on a server.
| Format | Best for |
|---|---|
| gzip | Interop with servers, logs and APIs — the common "gzip + Base64" blob format. Has a small header and checksum. |
| deflate (zlib) | The same DEFLATE stream with a 2-byte zlib wrapper — what most libraries call "deflate". |
| deflate (raw) | Bare DEFLATE, smallest output of the three — when the other side expects no wrapper. |
| LZ-string | Sharing state in URLs. Its URL-safe mode uses only URL-legal characters and needs the LZ-string library on the other side. |
Compressed-then-Base64'd payloads show up everywhere: config blobs, API responses, log fields, JWT-adjacent claims. Most online decoders make you paste that data into an ad-filled page that ships it to a server. Here the blob is decoded and inflated on your device — nothing leaves the tab, so it's safe even when the payload contains tokens or secrets.
Standard Base64 uses +, / and =, which need percent-encoding inside URLs. The URL-safe variant swaps them for - and _ and drops the padding, so the result can go straight into a query string.
Yes. Everything runs in your browser tab and keeps working offline once the page has loaded. Nothing you paste is sent anywhere.