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)
Decode one Base64 Brotli stream to UTF-8 text locally, with size limits, cancellation and complete-result copying Runs entirely in-memory using Web Crypto primitives to keep sensitive tokens, certificates, and cryptographic keys secure from third-party interception.
Encoding & cryptographic principles
Decompress one .br file or a Base64 Brotli stream locally. Download the exact restored bytes; valid UTF-8 is also shown as text, preserving BOM and NUL. The filename removes the final .br; Brotli stores no original filename or MIME type. Rename the download if needed. The installed brotli-dec-wasm decoder runs in a WebAssembly worker, using its Rust Brotli implementation; it is not an official Google package. No upload or paid service is used. Offline operation requires page resources to have loaded. Truncated streams, trailing or concatenated streams, shared dictionaries and large-window extensions are unsupported. Base64 accepts ASCII whitespace and optional canonical padding.
Worked verification example
Scenario: Inspect the text in one Base64 Brotli stream.
Sample input:
Second field:
Processing: Click “Run locally” and compare the complete UTF-8 output with CZOA Brotli fixture.
Illustrative output:
Security parameters & input constraints
Operational constraints and validation boundaries: Files must be smaller than 30,000,000 bytes (30 MB). Base64 remains limited to 2,097,152 characters including whitespace and 1 MiB of compressed bytes. Output is limited to 64 MiB (67,108,864 bytes). Startup: 10 seconds; decompression: 3 seconds. Some inputs below the size limit may still exceed output or time budgets. Cancel, edit, change input type, load sample or clear to discard pending work. Long text is paged; Copy and Download use the complete result.
Cryptographic digests, encoded strings, and signatures generated by Brotli Decompressor (WASM) should be verified against target authentication systems before production use.
Client-side Web Crypto boundary
Key derivation, hashing, and encoding in Brotli Decompressor (WASM) execute in local memory using Web Crypto APIs without remote socket transmission.
Cryptographic specifications & RFC standards
Technical specifications and cryptographic RFC standards governing algorithms and key representations:
- RFC 7932, sections 9–10: base Brotli format and decoding.
- RFC 4648, sections 3.5 and 4: Base64 and zero unused padding bits.
- WHATWG Encoding: fatal UTF-8 decoding, preserving a leading BOM.
- RFC 9841 extensions: shared dictionaries, framing and large windows are not implemented.
Brotli Decompressor (WASM) verification · Audit standards
How to use it
- Choose a .br file or paste Base64.
- Run locally to restore the bytes and preview valid UTF-8.
- Download the complete file, or copy the complete text.
Brotli (RFC 7932) vs Gzip (RFC 1952): Compression Algorithms, Dictionaries, and Web Performance →
An exhaustive engineering deep-dive into LZ77, Huffman coding, static pre-built dictionaries, WOFF2 fonts, Content-Encoding negotiation, and CPU-vs-bandwidth tradeoffs.
Frequently asked questions
What can I restore?+
Operational requirements for "What can I restore?" are verified in local memory during execution of Brotli Decompressor (WASM).
What are the limits?+
Files must be smaller than 30,000,000 bytes (30 MB).
Does this upload my file?+
Runtime handling of "Does this upload my file?" executes synchronously in your browser tab without remote delays.
How are invalid streams handled?+
Invalid, corrupted, or truncated Brotli streams trigger an immediate decoding error in the WebAssembly worker without crashing the browser tab. The tool displays a diagnostic error message indicating invalid stream headers or corrupt input bytes, and safely resets memory buffers.