Package jsoniter implements encoding and decoding of JSON as defined in RFC 4627 and provides interfaces with identical syntax of standard lib encoding/json. Converting from encoding/json to jsoniter is no more than replacing the package with jsoniter and variable type declarations (if any). jsoniter interfaces gives 100% compatibility with code using standard lib. "JSON and Go" (https://golang.org/doc/articles/json_and_go.html) gives a description of how Marshal/Unmarshal operate between arbitrary or predefined json objects and bytes, and it applies to jsoniter.Marshal/Unmarshal as well. Besides, jsoniter.Iterator provides a different set of interfaces iterating given bytes/string/reader and yielding parsed elements one by one. This set of interfaces reads input as required and gives better performance.