Core Breadcrumb Builders

When to Use

Know which builder handles which route so you can decide where to inject custom logic. All core builders register at priority 0 except where noted.

Items

PathBasedBreadcrumbBuilder

Description: The default catch-all builder. Always returns TRUE from applies(). Walks the URL path backwards segment-by-segment, builds a request for each parent path, checks access, resolves the title via TitleResolverInterface, and builds links.

Priority: 0 (fallback for all routes)

Key behaviors: - Adds url.path.parent and url.path.is_front cache contexts - Returns empty breadcrumb on the front page - Skips /user (hardcoded exclusion — acknowledged as a TODO in core) - Skips front page path from config system.site:page.front - Performs access checks per segment — segments the current user cannot access are silently omitted - Uses path aliases: the alias hierarchy defines breadcrumb structure (e.g., /blog/category/post yields /blog + /blog/category as crumbs) - Title resolution: calls TitleResolver::getTitle() which requires the route to define _title or _title_callback; routes without these get no segment

Gotchas: Segments without a _title or _title_callback defined on their route are silently dropped. This is why Easy Breadcrumb is usually preferred — it falls back to the URL slug instead of dropping the crumb.

TermBreadcrumbBuilder

Description: Handles entity.taxonomy_term.canonical routes specifically. Walks the term's parent hierarchy using loadAllParents().

Priority: 0 (same as PathBased, but applies() checks route name so it wins for taxonomy routes when priority ties are resolved by registration order)

Key behaviors: - Only applies when route is entity.taxonomy_term.canonical and the parameter is a TermInterface - Adds route cache context in applies() (Drupal 12 will formalize this; until then it is also added in build()) - Calls addCacheableDependency($term) even for the current term (not shown in crumb) — parent changes must invalidate the crumb - Resolves translation via EntityRepositoryInterface::getTranslationFromContext()

Gotchas: Does NOT add the vocabulary or any intermediate category link unless the term hierarchy includes parent terms. Single-level taxonomies produce just Home + current term.

CommentBreadcrumbBuilder

Description: Handles comment.reply routes (the comment reply form). Produces: Home → [Commented Entity] → [Parent Comment if replying to a comment].

Priority: 0

Key behaviors: - Adds route cache context - Adds the commented entity as a cacheable dependency - Adds the parent comment as a cacheable dependency if pid parameter is present

HelpBreadcrumbBuilder

Description: Handles help.help_topic routes. Produces: Home → Administration → Help.