# Intro to Guides

This section explains how certain functionalities have been implemented by GraphQL by PoP, and how the developer can replicate them for their custom APIs.

Guide Description
Rapid Iteration on the Schema Exemplifies the best strategy to follow to allow autonomous teams work on the same schema, without conflicts or tooling
Versioning fields and directives When upgrading the API, how to avoid breaking any client while keeping the schema as neat as possible
Sending a Localized Newsletter, User by User Step-by-step description of sending newsletters translated to the recipient's language, using a single PQL query
Building a CMS-agnostic API Concepts and code which make GraphQL by PoP core code, and a custom API, be CMS-agnostic
(x) Filling a Void with a Directive How directives enable to implement novel functionalities, not yet supported by the server
(x) Creating a Custom Access Control Rule How we can define custom rules for an Access Control List, to manage who can access a certain field or directive
(x) Executing the Backend for Frontends Pattern Learn how to implement the BFF pattern, where a single source of truth contains all the data for multiple applications (website, app, etc), and exposes to each application only the data it needs
Last Updated: 4/21/2020, 4:48:33 PM