According to official regulations, or the rules that govern a particular activity or industry, there are several synonyms that can be used interchangeably. Some of the most common synonyms for this phrase include "in compliance with official guidelines," "as per official standards," "following established protocols," and "in adherence to official policies." Other possible synonyms include "by the book," "in accordance with norms," "in keeping with regulations," and "as per the rules." No matter which synonym is used, the phrase typically refers to the idea that something is being done in accordance with the official rules and guidelines that govern the activity or industry in question.