JSON to BSON Converter

JSON to BSON Converter encodes a JSON document into BSON — the compact binary format MongoDB uses internally to store and transmit documents. Paste in JSON and the tool builds a spec-compliant BSON byte stream, complete with the correct type tags, length prefixes, and little-endian number encoding, so you can see exactly how MongoDB would represent your document on disk.

The output is shown as a readable hex dump for inspection, and can be downloaded as a raw .bson file for use with tooling that expects MongoDB's native binary format.

• Spec-compliant encoding: Correct BSON type codes, length-prefixed strings, and little-endian integers and doubles.
• Automatic type selection: Whole numbers in 32-bit range become BSON int32; everything else becomes a BSON double, matching standard JSON-to-BSON driver behavior.
• Nested documents and arrays: Objects and arrays of any depth are encoded as embedded BSON documents.
• Hex preview: Inspect the exact encoded bytes before downloading.
• Download as .bson: Get a raw binary file ready for BSON-aware tooling.

1. Paste your JSON into the input box, or click "Load Sample" to see an example.
2. Click Encode to BSON to generate the binary output.
3. Review the hex preview and byte count.
4. Download the .bson file for use with BSON-aware tools or MongoDB tooling.

Example 1: A simple document {"name":"Jane","age":30,"active":true} encodes to a compact BSON byte stream with a string element for name, an int32 element for age, and a boolean element for active, each preceded by its type byte and field name.

Example 2: A document with a nested address object and a tags array encodes each nested structure as its own embedded BSON document, exactly as MongoDB would store it internally.

• Understand MongoDB storage: See exactly how a document maps to BSON's binary representation.
• Generate test fixtures: Produce real .bson byte streams for testing BSON-aware code.
• No installation needed: No MongoDB driver or command-line tool required — everything runs in your browser.
• 100% private: Nothing is uploaded — encoding runs locally in your browser.