| bytes | Package bytes implements functions for the manipulation of byte slices. |
| encoding/json | Package json implements encoding and decoding of JSON as defined in RFC 7159. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| io | Package io provides basic interfaces to I/O primitives. |
| math/big | Package big implements arbitrary-precision arithmetic (big numbers). |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |