What is JSON / MessagePack Converter?
JSON and MessagePack Converter helps inspect binary API, cache, and queue payloads. It encodes JSON with a browser-side codec and represents the resulting bytes as Base64; decoding validates the carrier and accepts only values that can be represented safely as ordinary JSON. Common workflows include the following. Generate MessagePack bytes for an API test fixture. Decode MessagePack Base64 found in logs into readable JSON. Compare textual JSON and binary serialization size or structure. The page also documents input boundaries, output behavior, and practical cautions so you can review the result before putting it into an application, configuration, test, or production workflow.
When to use it
- Generate MessagePack bytes for an API test fixture.
- Decode MessagePack Base64 found in logs into readable JSON.
- Compare textual JSON and binary serialization size or structure.
How to use it
- Choose encode or decode.
- Use strict JSON for encoding or complete Base64 for decoding.
- Run and review type-safety messages.
- Copy the Base64 or formatted JSON.
- Load one of the realistic examples first to verify the selected options and processing direction before replacing it with your own data.
- Review the output, status message, and documented limits; copy, download, or continue only after the result matches your expectation.
Runnable examples
The “Example 1” and “Example 2” buttons load the matching inputs. They cover different structures, directions, or boundaries and can be run directly in the workspace.
Example 1
{"site":"JSONLane","release":{"tools":40,"ready":true},"tags":["local","browser"]}Example 2
g6RzaXRlqEpTT05MYW5lpXRvb2xzKA==Input rules
- Encoding requires strict JSON input.
- Decoding requires complete, correctly padded standard Base64.
- Extension values, non-finite numbers, and unsafe integers are rejected.
- Text input is counted before processing and is limited to 1,500,000 characters on this page; file modes apply the separate file limit shown in the workspace.
- Binary output is displayed as Base64 rather than hexadecimal.
Output rules
- MessagePack bytes are emitted as standard Base64 text.
- Decoded JSON uses two-space indentation.
- The target system must decode Base64 to recover the original bytes.
- Output reflects only the current input, direction, and options; rerun after changing a mode or value instead of treating an earlier result as current.
- Extension types and non-JSON values are rejected.
Limitations and cautions
- Binary output is displayed as Base64 rather than hexadecimal.
- Extension types and non-JSON values are rejected.
- Unsafe integers cannot silently become ordinary JSON numbers.
How your data is handled
All parsing, conversion, binary encoding, and intermediate data remain in the current browser tab. JSONLane does not upload the input or retain it after refresh or close.