BSON to JSON (text) Converter

You pulled a document out of MongoDB with mongodump, opened it in a hex editor and now you are staring at a wall of bytes. Or a binary blob showed up in a log and you need to know which fields live inside it before writing any code. Paste the hex into the top box and the document appears as indented JSON right below. Whitespace and a leading 0x are ignored.

The decoder reads the 32-bit length header, walks the type-name-value triples and stops at the trailing null byte. It handles double, string, embedded document, array, binary, ObjectId, boolean, UTC datetime, null, int32, timestamp and int64. Binary values and ObjectIds come back as text starting with 0x rather than the EJSON $oid form shown in the explainer. A datetime becomes a millisecond number such as 1715253010752, never an ISO string.

Anything outside that list stops the parse with a not-supported message and the type byte in hex: decimal128 (0x13), regular expressions (0x0b) and JavaScript code all land there. 64-bit integers above 2^53 arrive rounded, because the output goes through a JavaScript number. For whole files, or when those types matter, reach for the bson package on NPM. This page is for peeking at one small document fast, with nothing uploaded.