CBOR to JSON Online Converter

Debugging WebAuthn responses, IoT sensor data, or COSE security tokens? Paste CBOR data (base64 or hex) and get formatted JSON instantly.

To get started, just paste your CBOR value (in base64 or hex) or a JSON string into the respective input field above.

CBOR (Concise Binary Object Representation) is a binary data format that aims to be smaller and more efficient than JSON. It provides a compact binary representation of structured data, making it useful for scenarios where size and performance are important.

You'll commonly encounter CBOR in WebAuthn/FIDO2 attestation objects, IoT device communication (CoAP, MQTT), and COSE security tokens.

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This tool handles CBOR data types that don't have direct JSON equivalents:

• Buffer Handling — Stringified Buffer objects in JSON are automatically reconstructed when converting to CBOR.
• ArrayBuffer Display — Choose how to display binary data in JSON output: keep as-is, convert to base64, or convert to hex using the "Buffer Format" dropdown.
• Set Support — CBOR Sets are converted to Arrays by default. Toggle this in the settings menu (gear icon) to preserve original type information.