Decode Concise Binary Object Representation (CBOR) major types to JSON-friendly structures in your browser.
Privacy: Decoding runs entirely in this tab. Your bytes and optional schema text are not uploaded to Codeground servers.
Binary payload
Decoded output
{
"name": "Ada",
"id": 42
}CBOR (RFC 8949) powers WebAuthn, COSE, and constrained IoT payloads. This tool decodes unsigned/negative integers, byte/text strings, arrays, maps, tags, and simple values without a server round-trip.
Paste Base64, hex, or PEM (for ASN.1). Auto-detect treats even-length hex strings as hex; otherwise Base64 is assumed. Whitespace is stripped automatically.
Do you upload my binary payloads? No. Decoding runs entirely in your browser. Bytes and optional schemas never leave this tab.
Does this support indefinite-length CBOR? Not yet — paste definite-length DER-style CBOR (the common case in APIs and WebAuthn).
How are byte strings shown? As objects with $bytes (hex or UTF-8 when printable) and length.
What input formats work? Base64 or hex, with auto-detect.
Related: Protobuf decoder · MessagePack · CBOR · Base64 decode · JSON formatter