Protocols and binary formats
Inspect one BSON document or encode an Extended JSON object. The typed tree and canonical export preserve the meaning of MongoDB values.
Your input stays in this browser; this tool makes no database or network request.
EJSON uses two-space indentation. Input is processed only when you run it.
Choose bytes or an Extended JSON object to begin.
A BSON viewer is useful when a MongoDB collection file looks like unreadable bytes. A BSON to JSON shortcut can show the fields, yet an ordinary JSON conversion may hide whether a value was an ObjectId, Int64 or date.
Use this BSON decoder to inspect the type and absolute offset of each element before you share its Extended JSON. The reverse path creates a fresh BSON file from EJSON; it does not edit your source file.
See the bytes as fields while keeping their original types in sight.
The BSON viewer reads one complete document into an ordered tree. Each row shows the BSON type, value preview and absolute byte offset, so a bad length or unknown type points to a concrete place in the source.
Canonical Extended JSON wraps ObjectId, Int64, Decimal128 and binary subtypes instead of flattening them to ordinary JSON values. The relaxed view is available for reading, with a warning where round trips can lose a type.
Hex accepts spaces, colons and hyphens; base64 must be valid and explicitly selected. A .bson file replaces pasted bytes only after you confirm the preview.
Run decoding manually, then inspect the field order, type and byte offset. Switch between tree, canonical and relaxed EJSON without reparsing the bytes.
Copy canonical EJSON for type-aware review or download it as JSON; choose relaxed only when readability matters more than a safe type round trip. Encoding writes a new BSON file.
ObjectId, Int32, Int64, Decimal128, date, binary subtype and nested fields remain identifiable in the ordered tree.
The Extended JSON converter uses MongoDB type wrappers by default and offers a separate readable view that can lose type fidelity.
Encode a standard Extended JSON object and download new BSON bytes; hex or base64 makes the resulting payload easy to inspect.
For one BSON document, load the file here and download canonical Extended JSON. A collection dump normally contains several documents; this BSON viewer reports where the first ends and asks you to use bsondump for the full stream.
No. The scanner validates one whole document. If bytes remain after it, the error gives that absolute offset rather than showing only the first document as a successful result.
The relaxed EJSON view makes dates more readable, but canonical EJSON keeps explicit type wrappers. For an API that requires plain strings, transform those fields deliberately after inspection.
Switch to relaxed EJSON for an ISO date where MongoDB permits it. Canonical output keeps the millisecond value in a $date wrapper for stronger type preservation.
A plain JSON string has no BSON date type. Use an Extended JSON $date wrapper before encoding; then inspect the resulting BSON type in the tree.
Found a definition that should be supported?
Use the BSON viewer to trace one document from bytes to typed fields and canonical EJSON, then encode a new file only when needed.
Processing stays in this browser.