JSON to UBJSON

JSON to UBJSON encodes a JSON document as Universal Binary JSON — the compact binary format that reads like JSON but costs a fraction of the bytes. Integers shrink to their smallest fitting size, strings are length-prefixed UTF-8, and objects and arrays are typed containers.

• Automatic integer optimization: int8 / uint8 / int16 / int32 / int64 as needed.
• float64 for all floating point values.
• Typed containers: objects and arrays written in optimized form.
• Three outputs: hex, base64 and a downloadable .ubj file.
• Byte counts so you can see exactly what you saved.
• Private: All encoding happens in your browser.

1. Paste your JSON into the input box (or load the sample).
2. Encode and review the hex output.
3. Compare byte counts between the JSON text and the UBJSON binary.
4. Download the .ubj file if you need the real binary artifact.

Example 1 — Game networking. A developer encodes player state as UBJSON to cut payload size for a real-time multiplayer server.

Example 2 — IoT telemetry. An embedded engineer converts JSON sensor readings to UBJSON for a low-bandwidth uplink.

Example 3 — Caching. A backend team stores frequently-served JSON documents as UBJSON in Redis to save memory.

Example 4 — Protocol design. An architect prototypes a binary API by encoding sample JSON documents to compare sizes and structure.

• Smaller payloads: UBJSON is dramatically smaller than JSON text.
• No schema needed: Like JSON, it is self-describing.
• Widely supported: Parser libraries exist for every major language.
• Instant: Encoding happens in the browser in milliseconds.
• Zero upload: Data never leaves your machine.