Which feature allows you to preview code changes before they are merged?

The feature that allows you to preview code changes before they are merged is Review Apps. This capability is particularly valuable in a continuous development environment, as it provides a live preview of the application with the specific changes being proposed in a merge request.

When a developer creates a merge request, Review Apps automatically spins up a temporary environment where the changes are deployed. This means stakeholders can interact with the application and see how the new code integrates with the existing features in real-time. This functionality enhances collaboration and feedback during the development process, allowing teams to address potential issues early, ensuring that code changes meet the required standards before they are merged into the main branch.

In contrast, the other options focus on different elements of the software development lifecycle. Auto Deploy relates to the automation of the deployment process, Release Management encompasses the planning, scheduling, and controlling of software builds through different stages, and Continuous Integration deals with automatically building and testing code changes. While all these practices are crucial for maintaining software quality and streamlining the development process, they do not specifically provide the preview functionality that Review Apps offer.