CBOR Decoder
Parse CBOR (RFC 8949) data from hex or Base64URL input. Decodes all major types: integers, byte strings, text strings, arrays, maps, semantic tags, and simple values. Used in FIDO2/CTAP2, COSE, SenML, and CDDL development.
Presets:
Decoded Output
Paste CBOR data above and click Decode.
CBOR Major Types
| Type | Major (3 bits) | Description | Example |
|---|---|---|---|
| uint | 0 | Unsigned integer | 0x1a → 26 |
| nint | 1 | Negative integer | 0x20 → -1 |
| bytes | 2 | Byte string | 0x44 h'DEADBEEF' |
| text | 3 | UTF-8 text string | 0x64 "test" |
| array | 4 | Array (homogeneous) | 0x82 0x01 0x02 → [1,2] |
| map | 5 | Map (key-value) | 0xa1 0x01 0x02 → {1:2} |
| tag | 6 | Semantic tag | 0xc1 0x1a → epoch(26) |
| simple | 7 | Simple/float | 0xf4 → false, 0xfb → float64 |
Related
All decoding runs in your browser. No data is uploaded anywhere. CBOR (Concise Binary Object Representation) is defined in RFC 8949.