CBOR Decoder
Decode CBOR to JSON and to RFC 8949 diagnostic notation, see what each tag means, or encode JSON to CBOR as hex, Base64 or a file. Private.
Input
Stays in your browserShortcuts: Ctrl+Enter run · Ctrl+Shift+C copy result · / search (use ⌘ on Mac)
Next steps
Done here? Use the Send to… menu on the result to carry it on to JSON Beautifier or MessagePack Visualizer.
Free Online CBOR Decoder
Paste CBOR bytes to see them as JSON and in the standard diagnostic notation used in the specifications. It gives developers a quick browser-based way to solve a focused cbor decoder task before moving the result into a project.
How to use CBOR Decoder
Paste hex or Base64, or open a file, then press Decode. Tags are listed with their meaning.
Common mistakes
- Pasting JSON into the decode box: it expects hex or Base64 bytes.
- Expecting map keys other than text in JSON: they are turned into text there; the diagnostic notation keeps them.
Frequently asked questions
What is diagnostic notation?
A text form of CBOR defined in RFC 8949 that shows byte strings as h'0102', tags as 1(1363896240) and maps with any key type.
How are byte strings shown in JSON?
JSON has no bytes, so they appear as "hex:…". Use the diagnostic notation for the exact form.
What are tags?
Tags add meaning to a value, for example tag 1 is a date as seconds since 1970. Unknown tags are shown as tag(N) and are not an error.
Is my data uploaded?
No. Compression runs in your browser and nothing you paste or open is sent to a server.
How do I use this cbor decoder tool?
Use the interactive controls above; processing stays in your browser and the result is intended as a practical starting point for development work.
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