--- /dev/null
+<?php
+
+namespace Drupal\breakpoint;
+
+/**
+ * Defines an interface for breakpoint managers.
+ */
+interface BreakpointManagerInterface {
+
+ /**
+ * Gets breakpoints for the specified group.
+ *
+ * @param string $group
+ * The breakpoint group to retrieve.
+ *
+ * @return \Drupal\breakpoint\BreakpointInterface[]
+ * Array of breakpoint plugins keyed by machine name.
+ */
+ public function getBreakpointsByGroup($group);
+
+ /**
+ * Gets all the existing breakpoint groups.
+ *
+ * @return array
+ * Array of breakpoint group labels. Keyed by group name.
+ */
+ public function getGroups();
+
+ /**
+ * Gets all the providers for the specified breakpoint group.
+ *
+ * @param string $group
+ * The breakpoint group to retrieve.
+ *
+ * @return array
+ * An array keyed by provider name with values of provider type (module or
+ * theme).
+ */
+ public function getGroupProviders($group);
+
+}