Decode MessagePack binary data to readable JSON instantly. Paste hex bytes, a base64 string, or upload a .msgpack file — all processing happens in your browser.
MessagePack is a binary serialization format that packs data more efficiently than JSON — but that efficiency comes at the cost of human readability. This free MessagePack decoder lets you paste raw hex bytes, a base64-encoded blob, or upload a .msgpack file and instantly view the decoded data as formatted, readable JSON. No installation needed, no login, and nothing is sent to a server.
How to Decode MessagePack Online
- Choose your input method — paste hex-encoded bytes, paste a base64 string, or drag-and-drop a
.msgpackor.binfile into the tool. - Click "Decode" — the tool parses the binary MessagePack data entirely in your browser using JavaScript.
- View the decoded output — the result appears as pretty-printed JSON in the output panel.
- Copy or download — use the Copy button to grab the JSON, or download it as a
.jsonfile. - (Optional) Re-encode — toggle to encode JSON back to MessagePack hex or base64 if you need to reverse the operation.
Why Use Flipper File to Decode MessagePack?
- 100% browser-based — your binary data never leaves your machine; all decoding happens client-side with zero server uploads
- Multiple input formats — accepts raw hex bytes, base64-encoded strings, or direct file upload (
.msgpack,.bin) - Formatted JSON output — decoded data is pretty-printed and syntax-highlighted for easy reading
- Copy & download — grab decoded JSON instantly with one click, or save it as a
.jsonfile - Re-encode support — flip from JSON back to MessagePack hex or base64 without leaving the tool
- Completely free — no account, no watermarks, no rate limits, no paywalls
Frequently Asked Questions
What is MessagePack?
MessagePack (often called msgpack) is a binary serialization format designed as a compact, fast alternative to JSON. It encodes the same data types as JSON — strings, numbers, arrays, objects — but uses a binary representation that can be 2–4x smaller and faster to parse. It's commonly used in game backends, IoT devices, high-performance APIs, and caching layers like Redis.
Why does MessagePack data look like random bytes?
Because MessagePack is a binary format, it's not human-readable. When you open a .msgpack file in a text editor, you'll see garbled characters. You need a decoder (like this tool) to convert it back into a readable structure like JSON.
What input formats does this decoder accept?
This tool accepts three input formats: hexadecimal byte strings (e.g., 82 a7 63 6f 6d 70 61 63 74), base64-encoded strings (e.g., gqdzdHVkaW8=), and raw .msgpack or .bin file uploads via drag-and-drop.
Is this tool safe to use with sensitive data?
Yes. All decoding is done entirely in your browser using JavaScript — no data is transmitted to any server. Your binary payloads and decoded JSON stay on your machine.
Can I also encode JSON back to MessagePack?
Yes. The tool includes a reverse mode: paste valid JSON and it will encode it back to MessagePack, displayed as both hex bytes and a base64 string you can copy.
What happens if my input is invalid or corrupt?
The decoder will display a clear error message identifying where the parse failed. MessagePack data that is truncated, malformed, or not actually msgpack format will be caught gracefully without crashing the tool.
Does this tool support all MessagePack types?
Yes — the decoder handles all standard MessagePack types including nil, booleans, integers (signed and unsigned), floats (32-bit and 64-bit), strings, binary data, arrays, maps, and extension types. Extension types (Ext) are shown with their type code and raw bytes.
What file extensions are associated with MessagePack?
The most common extension is .msgpack, but you may also encounter .bin, .pack, or no extension at all, since MessagePack is often transmitted directly over the wire without a file wrapper.