Package codec provides a High Performance, Feature-Rich Idiomatic Go codec/encoding library for binc, msgpack, cbor, json. Supported Serialization formats are: For detailed usage information, read the primer at http://ugorji.net/blog/go-codec-primer . The idiomatic Go support is as seen in other encoding packages in the standard library (ie json, xml, gob, etc). Rich Feature Set includes: We gain performance by code-generating fast-paths for slices and maps of built-in types, and monomorphizing generic code explicitly so we gain inlining and de-virtualization benefits. The results are 20-50% performance improvements over v1.2. Building and running is configured using build tags as below. At runtime: - codec.safe: run in safe mode (not using unsafe optimizations) - codec.notmono: use generics code (bypassing performance-boosting monomorphized code) - codec.notfastpath: skip fast path code for slices and maps of built-in types (number, bool, string, bytes) Each of these "runtime" tags have a convenience synonym i.e. safe, notmono, notfastpath. Pls use these mostly during development - use codec.XXX in your go files. Build only: - codec.build: used to generate fastpath and monomorphization code Test only: - codec.notmammoth: skip the mammoth generated tests Users can register a function to handle the encoding or decoding of their custom types. There are no restrictions on what the custom type can be. Some examples: As an illustration, MyStructWithUnexportedFields would normally be encoded as an empty map because it has no exported fields, while UUID would be encoded as a string. However, with extension support, you can encode any of these however you like. There is also seamless support provided for registering an extension (with a tag) but letting the encoding mechanism default to the standard way. This package maintains symmetry in the encoding and decoding halfs. We determine how to encode or decode by walking this decision tree This symmetry is important to reduce chances of issues happening because the encoding and decoding sides are out of sync e.g. decoded via very specific encoding.TextUnmarshaler but encoded via kind-specific generalized mode. Consequently, if a type only defines one-half of the symmetry (e.g. it implements UnmarshalJSON() but not MarshalJSON() ), then that type doesn't satisfy the check and we will continue walking down the decision tree. RPC Client and Server Codecs are implemented, so the codecs can be used with the standard net/rpc package. The Handle is SAFE for concurrent READ, but NOT SAFE for concurrent modification. The Encoder and Decoder are NOT safe for concurrent use. Consequently, the usage model is basically: Sample usage model: To run tests, use the following: To run the full suite of tests, use the following: You can run the tag 'codec.safe' to run tests or build in safe mode. e.g. You can run the tag 'codec.notmono' to build bypassing the monomorphized code e.g. Running Benchmarks Please see http://github.com/ugorji/go-codec-bench . Struct fields matching the following are ignored during encoding and decoding Every other field in a struct will be encoded/decoded. Embedded fields are encoded as if they exist in the top-level struct, with some caveats. See Encode documentation.