Apigee's API design best practices advocate for URI path versioning as the most straightforward and common approach. Placing the major version indicator at the beginning of the URL path (e.g., /v1) makes the API version explicit and unambiguous for consumers. This method simplifies routing logic within the Apigee gateway, as different versions can be directed to different API proxies or target endpoints based on the base path. It also ensures that URIs for specific resources remain unique across versions, which benefits caching and browser history.

A. GET /customers/{customend}/v1: Placing the version at the end of the path is unconventional and breaks the hierarchical structure of a RESTful URI, making it less intuitive.

B. GET /customers/v1/{customerid}: Inserting the version in the middle of the resource path is not a standard practice and can complicate parsing and routing rules within the API proxy.

D. GET /customers?customend={customerid}&version=v1: While versioning via a query parameter is a valid technique, it is not the primary method recommended by Apigee. It can complicate caching, as some caches ignore query parameters, and makes routing within the proxy less direct than path-based routing.

1. Apigee

"Web API Design: The Missing Link" Ebook: In the chapter on "Versioning

" the guide states

"The most straightforward approach to versioning is to include the version number in the URI path... This is the most common approach..." It provides the example http://api.example.com/v1/users

which directly supports the structure in option C.

2. Google Cloud Apigee Documentation

"Create an API proxy": In the tutorial for creating a new proxy

the example base path provided is /v1/weather. This demonstrates the recommended practice of including the version as the first segment of the URI path for clear identification and routing. (See the "Configure the proxy" section of the tutorial).

3. Google Cloud Apigee Documentation

"API proxy development overview": This document explains how the proxy.basepath flow variable is populated from the incoming request URL. Using a base path like /v1/customers allows for easy implementation of conditional flows based on the API version

which is a core Apigee development pattern.