UBJSON to JSON

UBJSON files and network payloads are compact but unreadable to the human eye. UBJSON to JSON decodes a Universal Binary JSON stream — markers, packed integers, typed containers, everything — into formatted JSON you can read, diff and paste into any tool.

• Full marker support: i, U, I, l, L, d, D, S, C, H, T, F, N, Z.
• Optimized containers: counts (#) and element types ($) decoded correctly.
• Safe int64: numbers within 2^53; larger values become strings with a warning.
• Flexible input: upload a .ubj file, or paste hex or base64.
• Byte-accurate errors: unknown markers and truncation report the offset.
• Private: All decoding happens in your browser.

1. Upload a .ubj file or paste the bytes as hex or base64.
2. Review the decoded JSON — every value, key and nesting level.
3. Copy or download the JSON document.

Example 1 — Game logs. A developer captures UBJSON telemetry packets, decodes them here, and inspects player state as JSON.

Example 2 — IoT gateways. An engineer decodes sensor payloads received as UBJSON to verify field values and units.

Example 3 — Cached documents. A backend engineer retrieves a UBJSON document from a cache and decodes it to confirm what was stored.

Example 4 — Protocol debugging. A support engineer decodes a hex dump from a network trace to read the message body.

• Instant: Files decode in the browser in milliseconds.
• Complete: Optimized forms and all numeric widths supported.
• Readable: int64 values never silently corrupt.
• Zero upload: Data never leaves your machine.
• No install: Works on any device with a browser.