BSON Inspector
Paste a BSON document as base64 or hex and see a typed element tree — or convert it to canonical MongoDB Extended JSON v2. ObjectId, dates, binary, int64, and decimal128 are all preserved. Runs entirely in your browser, no upload, no sign-up.
About this tool
Paste one BSON document as Base64 or hex and this tool decodes it into a readable,
ordered view. The default tree output shows every field name, BSON type, and
value, including nested documents and arrays. Switch to json when you need
canonical MongoDB Extended JSON v2 with $oid, $date, $binary,
$numberInt, $numberLong, $numberDecimal, $timestamp, and the other typed
wrappers preserved.
Use it for quick checks on mongodump fragments, driver test fixtures, or raw
binary payloads copied from logs. Hex input may include spaces, colons, or
dashes, so byte dumps are easy to paste. Everything runs locally in your browser;
the BSON bytes are not uploaded.
Worked example
The Base64 sample FgAAAAJoZWxsbwAGAAAAd29ybGQAAA== is the BSON document
{ "hello": "world" }. With Output format set to tree, the result is:
hello: String "world"
With Output format set to json and Indent set to 0, the same input
renders as compact Extended JSON:
{"hello":"world"}
Limits and edge cases
- The input must be exactly one complete BSON document, not a concatenated stream of multiple documents.
- File upload is not part of this page; Base64-encode a
.bsonfile or paste a hex dump instead. - Decimal128 values are rendered as canonical decimal strings, while unsupported or unknown element type bytes return an explicit parse error with an offset.
FAQ
What kind of BSON input should I paste?
Paste the bytes of a single BSON document as Base64 or hex. Base64 is the
default because it is compact and common for binary blobs in logs. Hex is useful
when you copied bytes from a debugger; spaces, : separators, and - separators
are ignored.
What is the difference between tree output and JSON output?
tree is a human inspection view: every line shows the field name, the BSON type,
and a readable value, with optional byte offsets. json emits canonical MongoDB
Extended JSON v2, preserving types that normal JSON cannot represent, such as
ObjectId, DateTime, int64, binary subtypes, Decimal128, MinKey, and MaxKey.
Can this open a .bson file directly?
No direct file picker is included in this generic tool page. Convert the file to
Base64 (for example with base64 file.bson) or to a hex dump, then paste that
text. Parsing still happens locally in WebAssembly after the text is pasted.
Why did I get a document length or terminator error?
BSON stores a document length at byte 0 and ends each document with a NUL byte. If the pasted bytes are truncated, include extra bytes, or represent multiple concatenated documents, those structure checks fail. Copy exactly one complete document and try again.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool bson-inspector "FgAAAAJoZWxsbwAGAAAAd29ybGQAAA=="New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/bson-inspector/?input=FgAAAAJoZWxsbwAGAAAAd29ybGQAAA%3D%3D&input_format=base64&output=tree&indent=2&show_offsets=trueMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.