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Guide

Gzip Decompress Online — Inflate Base64 / Hex Gzip (Gunzip in Browser)

Free gzip decompress online: paste Base64 or hex gzip data (H4sI / 1f8b) to inflate text, or compress text to gzip. Gunzip / ungzip in your browser—no upload.

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#gzip decompress#gzip decompress online#gunzip online#gzip compress#Base64#HTTP#Developer Tools

Gunzip without a terminal.

Spoold's Gzip Decompress & Compress tool inflates gzip payloads from Base64 or hex—or compresses text the other way. Perfect when a log or API body starts with H4sI or 1f 8b.

Open gzip decompress online →

How to recognize gzip

Gzip streams start with magic bytes 1f 8b. In Base64 that often appears as H4sI. If you see either, switch Spoold to Decompress (or leave Auto on) and gzip decompress online without installing gunzip.

ClueMeaning
1f 8bRaw gzip magic (hex dump / Wireshark)
H4sI…Typical Base64 of gzip (very common in JSON APIs)
Content-Encoding: gzipHTTP body is gzip; capture bytes then inflate

When you need it

HTTP Content-Encoding

Decode a captured gzip body from DevTools or a proxy export.

API / webhook dumps

Some APIs return gzip as Base64 inside JSON—inflate, then pretty-print with JSON Format.

Quick compress

Compress a fixture to gzip Base64 for tests without shell pipelines.

Hex debugging

Paste hex from a hexdump; pair with Hex Decode when needed.

How to decompress on Spoold

  1. Open /tools/gzip.
  2. Paste Base64 or hex gzip (or upload a .gz text payload).
  3. Use Decompress (Auto detects magic bytes when enabled).
  4. Copy the inflated text; format JSON if needed.

Tip: already-compressed formats

PNG, JPEG, and MP3 won't shrink usefully with gzip. This tool shines on text, JSON, HTML, and logs.

Related search terms

gzip decompress onlinegunzip onlineungzip onlinegzip compress onlineinflate gzip base64h4si decodecontent-encoding gzipdecompress gzip browser

Frequently asked questions

Can I gzip decompress online for free?
Yes. Spoold's gunzip online path runs in the browser via Compression Streams.
Is data uploaded?
No—compress/decompress stay local unless you explicitly share.
Why does my paste start with H4sI?
That’s almost always Base64 of a gzip stream. Paste it into Decompress mode.
Can I compress too?
Yes—switch to Compress to produce gzip (often Base64) for fixtures and tests.
What if inflate fails?
Confirm magic bytes / complete Base64. Truncated captures and non-gzip payloads (plain zlib, brotli) won’t parse as gzip.

Decompress gzip now

Paste H4sI… into the gzip decompress tool.

Gzip ToolBase64JSON Format

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Gzip Decompress Online — Inflate Base64 / Hex Gzip (Gunzip in Browser) | Blog | Spoold