01
Select the real input format
Hex is the default. Choose Base64 or Base64URL explicitly, or read a local .cbor file; guessing between alphabets can decode the wrong bytes.
Protocols & Binary Serialization
CBOR to JSON converterInspect every byte and type
Decode one CBOR item from Hex, Base64, Base64URL or a local file; inspect its tree and marked JSON mapping.
CBOR to JSON converter
Result
Enter data or load the example.
Processed locally in this browser; no payload is uploaded.
Options
Choose the input format explicitly; one complete CBOR item is expected.
Enter data or load the example.
A CBOR to JSON converter is useful when a compact payload carries tags, byte strings or map keys that plain JSON cannot name accurately. This page keeps those types visible instead of silently flattening them. Use the CBOR decoder to inspect a captured message, then switch to the CBOR encoder when you need new bytes from ordinary JSON.
Why use this CBOR to JSON converter
Follow bytes into a typed tree
A Hex payload becomes a field tree with byte offsets. A tag remains a tag, and a numeric map key stays numeric, so a CBOR viewer can show what the wire item actually contains.
Keep the JSON mapping explicit
This CBOR to JSON converter wraps every map as ordered entries and labels bytes, tags and unsafe integers. The mapping avoids inventing ordinary JSON values where the CBOR model is wider.
Choose the bytes, then verify the type
02
Watch when the result updates
Automatic conversion waits 350 ms after a change. Turn it off for manual runs with Ctrl/Cmd + Enter; old results cannot be copied after the input changes.
03
Compare tree and mapped JSON
The tree shows type and byte span; the JSON tab uses $cbor markers. A .json export is that mapping, while JSON→CBOR downloads raw .cbor bytes.
Read structure or produce new bytes
Decode common CBOR encodings
The CBOR decoder accepts definite and indefinite arrays, maps, byte and text strings, integers, floats, simple values and tags.
Inspect a type-aware mapping
The JSON view exposes ordered map entries, byte strings and numbered tags. It is a readable projection, not a claim that CBOR and JSON share one data model.
Encode plain JSON
JSON to CBOR turns objects, arrays, strings, booleans, null and safe numbers into a binary item; copy Hex or Base64 or download .cbor.
What this mapping preserves and cannot infer
- One complete item
- The CBOR to JSON converter rejects trailing bytes instead of silently treating a CBOR sequence as one value. Parse sequences with a dedicated stream tool.
- Marked JSON is a view
- All maps use $cbor entries, even string-key maps. The JSON→CBOR input accepts ordinary JSON and does not interpret those markers as a byte-perfect reverse format.
- Precision and resource limits
- Ordinary JSON integers beyond the JavaScript safe range are rejected on encode; decode labels large CBOR integers. Inputs are capped at 1 MiB, 10,000 nodes and 64 levels.
- No protocol validation
- A tag number is displayed, not treated as proof of COSE signatures, WebAuthn data, CDDL validity or trust. No URL is fetched.
CBOR to JSON converter questions
How do I decode a CBOR payload?
Choose Hex, Base64 or Base64URL, then paste one complete CBOR item. The default Hex sample demonstrates a tag, a byte string and a numeric map key.
How are large integers handled?
CBOR integers outside the safe JavaScript number range stay decimal strings inside a typed wrapper in the mapping. Ordinary JSON encoding rejects unsafe integer literals rather than rounding them.
What if the payload has trailing bytes?
Extra bytes after one data item cause a trailing-byte error with a byte offset. This tool does not automatically split a CBOR sequence.
Why is a byte string rendered as 0x...?
The mapping uses a $cbor bytes wrapper with a hex field, so a byte string cannot be mistaken for an ordinary text string.
Does it work with .cbor files?
Yes. The file input reads .cbor or .bin data with the browser File API and previews replacement before applying it; no upload is performed.
Still have a question?
Use the CBOR to JSON converter now
Inspect a captured CBOR item or encode a plain JSON value. The mapped output makes non-JSON types visible before you export.