You've updated your API backend. The changes are not backward compatible and will break consumers of your current API. What approach would best serve your customers?

Deploying two versions of your Cloud Endpoints API by creating a separate API configuration for each version is the best approach when dealing with non-backward compatible changes. This strategy allows you to maintain the original version of the API for existing consumers while also offering the new version for those who need or want to use the updated functionality.

By having both versions available, you provide flexibility to your users, allowing them to transition to the new API at their own pace. This approach reduces the risk of disrupting existing consumers’ applications, which can be critical in maintaining user trust and satisfaction. Moreover, providing clear documentation and deprecation timelines for the older version can further support a smooth transition for users, ensuring that they are well-informed about the changes and any necessary actions they may need to take.

This method of versioning APIs is a common best practice in API management, as it allows developers to iterate and improve their services without alienating their existing user base. It creates an environment where developers can innovate with new features while keeping previous functionalities intact until clients are ready to upgrade.