| encoding/json | Package json implements encoding and decoding of JSON as defined in RFC 7159. |
| errors | Package errors implements functions to manipulate errors. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| github.com/open-policy-agent/opa/internal/ref | Package ref implements internal helpers for references |
| github.com/open-policy-agent/opa/v1/ast | Package ast declares Rego syntax tree types and also includes a parser and compiler for preparing policies for execution in the policy engine. |
| github.com/open-policy-agent/opa/v1/util | Package util provides generic utilities used throughout the policy engine. |
| github.com/open-policy-agent/opa/v1/version | Package version contains version information that is set at build time. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| path/filepath | Package filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths. |
| reflect | Package reflect implements run-time reflection, allowing a program to manipulate objects with arbitrary types. |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |