Understanding Entity Reference Revisions in Drupal for Version‑Safe Nested Content

Entity Reference Revisions (ERR) is a field type in Drupal core that enhances content stability for nested structures such as those created with modules like Paragraphs and Inline Entity Form. Instead of linking a parent entity to the newest version of a referenced item, such as a paragraph block, banner, or section, ERR keeps a snapshot of the exact revision that was present when the parent was saved. This preserves editorial intent and prevents unintended content drift when parts of a page or node are updated independently.

Without Entity Reference Revisions, updates to a referenced item automatically propagate to all places it appears, which can lead to silent changes on live, published pages. ERR avoids this by “locking” the reference to a specific revision, making it possible to compare revisions accurately and support reliable rollbacks. This behaviour is especially valuable in moderated workflows and complex layouts where content integrity and historical fidelity matter.

The blog post walks through a simple example where enabling the Paragraphs module automatically activates ERR as a dependency, creating initial content, updating it to form a new revision, and then demonstrating how Drupal’s Revisions tab reflects both parent and nested entity states. It highlights that ERR enhances version control, supports smooth editorial workflows, and integrates seamlessly with core and contributed tools for structured content building.

In practice, developers and site builders should use Entity Reference Revisions when working with nested content that demands revision tracking—such as moderated editorial workflows or Layout Builder sections—while regular entity reference fields remain suitable for content that always needs the latest version, like global footers or contact info blocks.