Paste base64 or hexadecimal gzip data and decompress it into readable text in the browser.
Compression tool
Enter a value to see the result automatically.
Guide
Decompress Base64 or Hex gzip data online, inspect compressed and output sizes, and automatically pretty-print decoded JSON with browser-native processing.
Gzip is widely used for HTTP responses, logs, archives, API payloads, and compressed text samples. When a gzip value has been copied as base64 or hexadecimal, it is not easy to read without a decoder. This page gives you a focused way to decompress the payload in the browser.
The tool accepts base64 gzip data and even-length hexadecimal gzip data. It uses the browser DecompressionStream API when available, so the work happens locally in the page. That makes it convenient for quick debugging, documentation, and inspection of small compressed payloads.
This page is not meant to replace archive software for large files. It is designed for pasted strings, short examples, encoded API fields, and small diagnostics. If the compressed bytes are valid gzip and the decompressed content is text, the output area will show the readable result.
Be careful with unknown compressed data. Decompression can expand a small input into a much larger output. For everyday development checks, keep the input reasonably small and avoid pasting sensitive production data unless you understand your environment.
Quick reference
H4sIAAAAAAAAA/NIzcnJVyjPL8pJAQBSntaLCwAAAA==
Input encoding: Base64 / Compression wrapper: Gzip / Compressed size: 31 bytes / Decompressed size: 11 bytes / Output: Hello world
Gzip, zlib, and raw deflate are related but not interchangeable. A payload can fail simply because it is using a different wrapper.
The page is designed for pasted base64 or hexadecimal strings, not large binary archives or files.
Decompression uses browser-native APIs when available. Older browsers may not expose the required stream support.
In-depth guide
Successful decompression depends on both the compression wrapper and the way binary bytes were converted to text. This page identifies Base64 or Hex input and reports sizes before showing the decoded content.
Gzip adds a header, checksum, and trailer around deflate-compressed data. A zlib-wrapped payload is related but will not decode as gzip.
Base64 only represents bytes as text. Decode the Base64 layer first, then apply gzip decompression to the resulting bytes.
Even-length hexadecimal text can represent the same compressed bytes as Base64. A leading 0x is accepted for copied developer values.
UTF-8 text is displayed directly. When the decompressed text is valid JSON, the result is indented automatically for easier inspection.
Common mistakes
The tool accepts base64 gzip data and even-length hexadecimal gzip data.
The data may not be gzip, may be corrupted, or may use a wrapper such as zlib instead.
It requires browser support for DecompressionStream. Current Chromium, Edge, and Safari builds support it.
A common Base64 gzip prefix is H4sI because gzip bytes often begin with 1F 8B. The prefix is a clue, not a complete integrity check.
Gzip and zlib wrap deflate data differently. Use the zlib decompressor when the payload has a zlib wrapper.
Yes. If the decoded UTF-8 text parses as JSON, the result is automatically formatted with indentation.