Brotli Decompressor (WASM)
Decode one Base64 Brotli stream to UTF-8 text locally, with size limits, cancellation and complete-result copying.
About this brotli decompressor (wasm)
Brotli Decompressor (WASM) — browser-based utility.
How this tool works
The decoder checks Base64 syntax, then runs the RFC 7932 Brotli decoder in a fresh WebAssembly worker. Brotli reconstructs bytes using LZ77 back references, Huffman coding and its built-in static dictionary. The complete output is decoded as strict UTF-8; invalid text is rejected. The tool does not compress data, fetch URLs or accept files.
- Paste the Base64 example into “Base64 input”.
- Click “Run locally” and compare the complete UTF-8 output with CZOA Brotli fixture.
- Use Copy for the complete result. Cancel, edit, Clear or Load sample to stop the current task.
Worked example
Scenario: Inspect the text in one Base64 Brotli stream.
Sample input:
Processing: Click “Run locally” and compare the complete UTF-8 output with CZOA Brotli fixture.
Illustrative output:
Limits and verification
Base64 may contain ASCII spaces, tabs, CR and LF. Padding may be present or omitted, but unused padding bits must be zero. The input text limit is 2,097,152 characters including whitespace; compressed data is limited to 1 MiB and decompressed output to 8 MiB. Truncated streams, bytes after the first stream, concatenated streams and invalid UTF-8 are rejected. A leading UTF-8 BOM and NUL characters are preserved. Shared dictionaries and large-window extensions from RFC 9841 are not supported. Worker startup is limited to 10 seconds and decoding to 3 seconds. Editing, clearing, loading the example or cancelling terminates the current worker. Long input and output are displayed in pages; conversion and Copy use the complete text.
Examples demonstrate an expected workflow; they do not prove every input or every branch of an external specification. Check important results with an independent source before using them for money, security, compliance, safety, or irreversible file changes.
Browser processing boundary
Tool input is processed by code running in the browser and is not intentionally sent to a CZOA processing API. The page can still request ordinary site assets, analytics, or advertising when those services are enabled. Browser extensions and managed-device software remain outside this tool's control.
Relevant references
These references govern or help explain the format, protocol, or calculation used here. Listing a reference does not claim certification or complete implementation of every optional feature.
- RFC 7932 Sections 9 and 10 (Brotli; base format only)
- RFC 4648 Sections 3.5 and 4 (canonical Base64)
- WHATWG Encoding (fatal UTF-8 decoding)
Content owner: CZOA Tools · Last reviewed: 2026-09-15 · Review methodology
How to use it
- Paste the Base64 example into “Base64 input”.
- Click “Run locally” and compare the complete UTF-8 output with CZOA Brotli fixture.
- Use Copy for the complete result. Cancel, edit, Clear or Load sample to stop the current task.
Frequently asked questions
What does Brotli Decompressor require?+
It accepts Base64 Brotli bytes and runs a WebAssembly decoder inside a Worker.
What did the browser fixture verify?+
The built-in fixture CwmAQ1pPQSBCcm90bGkgZml4dHVyZQM= decoded to CZOA Brotli fixture.
Which browser capabilities are required?+
The path requires Worker and WebAssembly; missing capabilities enter an error state.
Does it compress Brotli data?+
No. This component only decodes supplied Brotli bytes and reports compressed and output sizes.