BSON Hex Viewer

About this calculator

BSON (Binary JSON) is the binary-encoded serialization format MongoDB uses to store documents and exchange them over its wire protocol — it extends JSON with extra types like dates and binary data, and every element in the byte stream follows the same layout: a one-byte type code, a null-terminated field-name string, and then the value encoded according to its type (e.g., a 32-bit little-endian integer, or a 4-byte length prefix followed by UTF-8 bytes for a string).

This viewer takes a small, single-field JSON document (one string or integer value) and encodes it exactly as MongoDB's driver would, then displays the resulting bytes as annotated hexadecimal — labeling the document length prefix, type byte, field name, and value bytes — so you can see how JSON's text representation maps onto BSON's compact binary layout without needing to run a database driver.