| 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. |
| github.com/open-policy-agent/opa/ast/json | Deprecated: This package is intended for older projects transitioning from OPA v0.x and will remain for the lifetime of OPA v1.x, but its use is not recommended. |
| 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. |
| io | Package io provides basic interfaces to I/O primitives. |