Currently the mogodb driver has support for Decimal128 bson type. However, this type is rather useless as no arithmetic operations are supported on it (only conversions from strings, etc.).

There is a decimal package for go with a rich API at

https://pkg.go.dev/github.com/shopspring/decimal

it would be nice to make compatible with this type or provide a similar API.

Note that a decimal type is very useful for instance in financial applications that require exact representation of the values.