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Standard Libraries

Gno comes with a set of standard libraries which are included to ease development and provide extended functionality to the language. These include:

  • standard libraries as we know them in classic Go, i.e. encoding/binary, strings, testing, etc.
  • a special std package, which contains types, interfaces, and APIs created to handle blockchain-related functionality.

Standard libraries differ from on-chain packages in terms of their import path structure. Unlike on-chain packages, standard libraries do not incorporate a domain-like format at the beginning of their import path. For example:

  • import "encoding/binary" refers to a standard library
  • import "" refers to an on-chain package.

To see concrete implementation details & API references, see the reference section.

Accessing documentation

Apart from the official documentation you are currently reading, you can also access documentation for the standard libraries in several other different ways. You can obtain a list of all the available standard libraries with the following commands:

$ cd gnovm/stdlibs # go to correct directory

$ find -type d

All the packages have automatically generated documentation through the use of the gno doc command, which has similar functionality and features to go doc:

$ gno doc encoding/binary
package binary // import "encoding/binary"

Package binary implements simple translation between numbers and byte sequences
and encoding and decoding of varints.


var BigEndian bigEndian
var LittleEndian littleEndian
type AppendByteOrder interface{ ... }
type ByteOrder interface{ ... }
$ gno doc -u -src encoding/binary littleEndian.AppendUint16
package binary // import "encoding/binary"

func (littleEndian) AppendUint16(b []byte, v uint16) []byte {
return append(b,

gno doc will work automatically when used within the Gno repository or any repository which has a go.mod dependency on

Another alternative is setting your environment variable GNOROOT to point to where you cloned the Gno repository.

export GNOROOT=$HOME/gno