diff --git a/shared/lib/Mail/Service/ServiceEntityMutableInterface.php b/shared/lib/Mail/Service/ServiceEntityMutableInterface.php
index 9736cd0..ef144e3 100644
--- a/shared/lib/Mail/Service/ServiceEntityMutableInterface.php
+++ b/shared/lib/Mail/Service/ServiceEntityMutableInterface.php
@@ -79,25 +79,23 @@ interface ServiceEntityMutableInterface extends ServiceBaseInterface {
      *
      * @since 2025.05.01
      *
-     * @param string|int $sourceCollection Source collection identifier
-     * @param string|int $targetCollection Target collection identifier
-     * @param string|int ...$identifiers Entity identifiers to copy
+     * @param string|int $target Target collection identifier
+     * @param array<string|int,array<string|int>> $sources Source entities to move (collection identifier => [entity identifier])
      *
-     * @return array<string|int,string|int> Map of source identifier => new identifier
+     * @return array<string|int,bool> List of moved entity identifiers
      */
-    public function entityCopy(string|int $sourceCollection, string|int $targetCollection, string|int ...$identifiers): array;
+    public function entityCopy(string|int $target, array $sources): array;
 
     /**
      * Moves entities to another collection
      *
      * @since 2025.05.01
-     *
-     * @param string|int $sourceCollection Source collection identifier
-     * @param string|int $targetCollection Target collection identifier
-     * @param string|int ...$identifiers Entity identifiers to move
+     * 
+     * @param string|int $target Target collection identifier
+     * @param array<string|int,array<string|int>> $sources Source entities to move (collection identifier => [entity identifier])
      *
      * @return array<string|int,bool> List of moved entity identifiers
      */
-    public function entityMove(string|int $sourceCollection, string|int $targetCollection, string|int ...$identifiers): array;
+    public function entityMove(string|int $target, array $sources): array;
 
 }
diff --git a/shared/lib/Resource/Identifier/CollectionIdentifier.php b/shared/lib/Resource/Identifier/CollectionIdentifier.php
new file mode 100644
index 0000000..4f9ed5f
--- /dev/null
+++ b/shared/lib/Resource/Identifier/CollectionIdentifier.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace KTXF\Resource\Identifier;
+
+/**
+ * Collection-level resource identifier (depth 3)
+ * 
+ * Format: {provider}:{service}:{collection}
+ */
+class CollectionIdentifier extends ServiceIdentifier implements CollectionIdentifierInterface {
+
+	public function __construct(
+		string $provider,
+		string $service,
+		private readonly string $_collection,
+	) {
+		parent::__construct($provider, $service);
+	}
+
+	public function collection(): string {
+		return $this->_collection;
+	}
+
+	public function depth(): int {
+		return 3;
+	}
+
+	public function __toString(): string {
+		return parent::__toString() . self::SEPARATOR . $this->_collection;
+	}
+
+}
diff --git a/shared/lib/Resource/Identifier/CollectionIdentifierInterface.php b/shared/lib/Resource/Identifier/CollectionIdentifierInterface.php
new file mode 100644
index 0000000..a8a4c20
--- /dev/null
+++ b/shared/lib/Resource/Identifier/CollectionIdentifierInterface.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace KTXF\Resource\Identifier;
+
+/**
+ * Collection-level identifier (provider + service + collection)
+ */
+interface CollectionIdentifierInterface extends ServiceIdentifierInterface {
+
+	/** The collection segment (e.g. "inbox") */
+	public function collection(): string;
+
+}
diff --git a/shared/lib/Resource/Identifier/EntityIdentifier.php b/shared/lib/Resource/Identifier/EntityIdentifier.php
new file mode 100644
index 0000000..5266c54
--- /dev/null
+++ b/shared/lib/Resource/Identifier/EntityIdentifier.php
@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace KTXF\Resource\Identifier;
+
+/**
+ * Entity-level resource identifier (depth 4)
+ * 
+ * Format: {provider}:{service}:{collection}:{entity}
+ */
+class EntityIdentifier extends CollectionIdentifier implements EntityIdentifierInterface {
+
+	public function __construct(
+		string $provider,
+		string $service,
+		string $collection,
+		private readonly string $_entity,
+	) {
+		parent::__construct($provider, $service, $collection);
+	}
+
+	public function entity(): string {
+		return $this->_entity;
+	}
+
+	public function depth(): int {
+		return 4;
+	}
+
+	public function __toString(): string {
+		return parent::__toString() . self::SEPARATOR . $this->_entity;
+	}
+
+}
diff --git a/shared/lib/Resource/Identifier/EntityIdentifierInterface.php b/shared/lib/Resource/Identifier/EntityIdentifierInterface.php
new file mode 100644
index 0000000..21bb571
--- /dev/null
+++ b/shared/lib/Resource/Identifier/EntityIdentifierInterface.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace KTXF\Resource\Identifier;
+
+/**
+ * Entity-level identifier (provider + service + collection + entity)
+ */
+interface EntityIdentifierInterface extends CollectionIdentifierInterface {
+
+	/** The entity segment (e.g. "1001") */
+	public function entity(): string;
+
+}
diff --git a/shared/lib/Resource/Identifier/ResourceIdentifier.php b/shared/lib/Resource/Identifier/ResourceIdentifier.php
new file mode 100644
index 0000000..edf929c
--- /dev/null
+++ b/shared/lib/Resource/Identifier/ResourceIdentifier.php
@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace KTXF\Resource\Identifier;
+
+/**
+ * Provider-level resource identifier (depth 1)
+ * 
+ * Format: {provider}
+ */
+class ResourceIdentifier implements ResourceIdentifierInterface {
+
+	public const SEPARATOR = ':';
+
+	public function __construct(
+		private readonly string $provider,
+	) {
+	}
+
+	public function provider(): string {
+		return $this->provider;
+	}
+
+	public function depth(): int {
+		return 1;
+	}
+
+	public function __toString(): string {
+		return $this->provider;
+	}
+
+	/**
+	 * Parse a colon-separated identifier string and return the appropriate level class
+	 * 
+	 * @return ResourceIdentifier|ServiceIdentifier|CollectionIdentifier|EntityIdentifier
+	 */
+	public static function fromString(string $identifier): ResourceIdentifierInterface {
+		$parts = explode(self::SEPARATOR, $identifier, 4);
+		if (count($parts) < 1 || $parts[0] === '') {
+			throw new \InvalidArgumentException("Invalid resource identifier: {$identifier}");
+		}
+
+		return match (count($parts)) {
+			4       => new EntityIdentifier($parts[0], $parts[1], $parts[2], $parts[3]),
+			3       => new CollectionIdentifier($parts[0], $parts[1], $parts[2]),
+			2       => new ServiceIdentifier($parts[0], $parts[1]),
+			default => new self($parts[0]),
+		};
+	}
+
+}
diff --git a/shared/lib/Resource/Identifier/ResourceIdentifierInterface.php b/shared/lib/Resource/Identifier/ResourceIdentifierInterface.php
new file mode 100644
index 0000000..ee5ddc7
--- /dev/null
+++ b/shared/lib/Resource/Identifier/ResourceIdentifierInterface.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace KTXF\Resource\Identifier;
+
+/**
+ * Top-level identifier for resources (provider level)
+ */
+interface ResourceIdentifierInterface extends \Stringable {
+
+	/** The provider segment (e.g. "imap") */
+	public function provider(): string;
+
+	/** Number of segments present (1–4) */
+	public function depth(): int;
+
+	/** Canonical string form: provider[:service[:collection[:entity]]] */
+	public function __toString(): string;
+
+}
diff --git a/shared/lib/Resource/Identifier/ResourceIdentifiers.php b/shared/lib/Resource/Identifier/ResourceIdentifiers.php
new file mode 100644
index 0000000..e0c1c2a
--- /dev/null
+++ b/shared/lib/Resource/Identifier/ResourceIdentifiers.php
@@ -0,0 +1,154 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace KTXF\Resource\Identifier;
+
+/**
+ * Typed collection of resource identifiers
+ * 
+ * Accepts an array of identifier strings (e.g. ["imap:account1:inbox:1001", "imap:account1:sent"])
+ * and provides filtering/search helpers.
+ */
+class ResourceIdentifiers implements ResourceIdentifiersInterface {
+
+	/** @var ResourceIdentifierInterface[] */
+	private array $identifiers = [];
+
+	/** Create a collection from an array of identifier strings */
+	public static function fromArray(array $strings): static {
+		$collection = new static();
+		foreach ($strings as $string) {
+			if (!is_string($string)) {
+				throw new \InvalidArgumentException('Each identifier must be a string');
+			}
+			$collection->add(ResourceIdentifier::fromString($string));
+		}
+		return $collection;
+	}
+
+	public function add(ResourceIdentifierInterface $identifier): void {
+		$this->identifiers[] = $identifier;
+	}
+
+	/** @return ResourceIdentifierInterface[] */
+	public function all(): array {
+		return $this->identifiers;
+	}
+
+	public function count(): int {
+		return count($this->identifiers);
+	}
+
+	public function getIterator(): \ArrayIterator {
+		return new \ArrayIterator($this->identifiers);
+	}
+
+	/** Filter identifiers by depth level (1–4) */
+	public function byDepth(int $depth): static {
+		$filtered = new static();
+		foreach ($this->identifiers as $id) {
+			if ($id->depth() === $depth) {
+				$filtered->add($id);
+			}
+		}
+		return $filtered;
+	}
+
+	/** Filter identifiers by provider */
+	public function byProvider(string $provider): static {
+		$filtered = new static();
+		foreach ($this->identifiers as $id) {
+			if ($id->provider() === $provider) {
+				$filtered->add($id);
+			}
+		}
+		return $filtered;
+	}
+
+	/** Filter identifiers by service (only identifiers with depth >= 2) */
+	public function byService(string $service): static {
+		$filtered = new static();
+		foreach ($this->identifiers as $id) {
+			if ($id instanceof ServiceIdentifierInterface && $id->service() === $service) {
+				$filtered->add($id);
+			}
+		}
+		return $filtered;
+	}
+
+	/** Filter identifiers by collection (only identifiers with depth >= 3) */
+	public function byCollection(string $collection): static {
+		$filtered = new static();
+		foreach ($this->identifiers as $id) {
+			if ($id instanceof CollectionIdentifierInterface && $id->collection() === $collection) {
+				$filtered->add($id);
+			}
+		}
+		return $filtered;
+	}
+
+	/** Filter identifiers by entity (only identifiers with depth == 4) */
+	public function byEntity(string $entity): static {
+		$filtered = new static();
+		foreach ($this->identifiers as $id) {
+			if ($id instanceof EntityIdentifierInterface && $id->entity() === $entity) {
+				$filtered->add($id);
+			}
+		}
+		return $filtered;
+	}
+
+	/** Get unique provider names */
+	public function providers(): array {
+		$values = [];
+		foreach ($this->identifiers as $id) {
+			$values[$id->provider()] = true;
+		}
+		return array_keys($values);
+	}
+
+	/** Get unique service names */
+	public function services(): array {
+		$values = [];
+		foreach ($this->identifiers as $id) {
+			if ($id instanceof ServiceIdentifierInterface) {
+				$values[$id->service()] = true;
+			}
+		}
+		return array_keys($values);
+	}
+
+	/** Get unique collection names */
+	public function collections(): array {
+		$values = [];
+		foreach ($this->identifiers as $id) {
+			if ($id instanceof CollectionIdentifierInterface) {
+				$values[$id->collection()] = true;
+			}
+		}
+		return array_keys($values);
+	}
+
+	/** Get unique entity names */
+	public function entities(): array {
+		$values = [];
+		foreach ($this->identifiers as $id) {
+			if ($id instanceof EntityIdentifierInterface) {
+				$values[$id->entity()] = true;
+			}
+		}
+		return array_keys($values);
+	}
+
+	/** Check if the collection is empty */
+	public function isEmpty(): bool {
+		return count($this->identifiers) === 0;
+	}
+
+}
diff --git a/shared/lib/Resource/Identifier/ResourceIdentifiersInterface.php b/shared/lib/Resource/Identifier/ResourceIdentifiersInterface.php
new file mode 100644
index 0000000..c59c3dd
--- /dev/null
+++ b/shared/lib/Resource/Identifier/ResourceIdentifiersInterface.php
@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace KTXF\Resource\Identifier;
+
+/**
+ * A typed collection of resource identifiers with search and filter capabilities
+ */
+interface ResourceIdentifiersInterface extends \Countable, \IteratorAggregate {
+
+	/** Add an identifier to the collection */
+	public function add(ResourceIdentifierInterface $identifier): void;
+
+	/** Get all identifiers */
+	public function all(): array;
+
+	/** Filter identifiers by depth level (1–4) */
+	public function byDepth(int $depth): static;
+
+	/** Filter identifiers by provider */
+	public function byProvider(string $provider): static;
+
+	/** Filter identifiers by service (requires depth >= 2) */
+	public function byService(string $service): static;
+
+	/** Filter identifiers by collection (requires depth >= 3) */
+	public function byCollection(string $collection): static;
+
+	/** Filter identifiers by entity (requires depth == 4) */
+	public function byEntity(string $entity): static;
+
+	/** Get unique provider names */
+	public function providers(): array;
+
+	/** Get unique service names */
+	public function services(): array;
+
+	/** Get unique collection names */
+	public function collections(): array;
+
+	/** Get unique entity names */
+	public function entities(): array;
+
+}
diff --git a/shared/lib/Resource/Identifier/ServiceIdentifier.php b/shared/lib/Resource/Identifier/ServiceIdentifier.php
new file mode 100644
index 0000000..dda1437
--- /dev/null
+++ b/shared/lib/Resource/Identifier/ServiceIdentifier.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace KTXF\Resource\Identifier;
+
+/**
+ * Service-level resource identifier (depth 2)
+ * 
+ * Format: {provider}:{service}
+ */
+class ServiceIdentifier extends ResourceIdentifier implements ServiceIdentifierInterface {
+
+	public function __construct(
+		string $provider,
+		private readonly string $_service,
+	) {
+		parent::__construct($provider);
+	}
+
+	public function service(): string {
+		return $this->_service;
+	}
+
+	public function depth(): int {
+		return 2;
+	}
+
+	public function __toString(): string {
+		return parent::__toString() . self::SEPARATOR . $this->_service;
+	}
+
+}
diff --git a/shared/lib/Resource/Identifier/ServiceIdentifierInterface.php b/shared/lib/Resource/Identifier/ServiceIdentifierInterface.php
new file mode 100644
index 0000000..fa90374
--- /dev/null
+++ b/shared/lib/Resource/Identifier/ServiceIdentifierInterface.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: Sebastian Krupinski <krupinski01@gmail.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace KTXF\Resource\Identifier;
+
+/**
+ * Service-level identifier (provider + service)
+ */
+interface ServiceIdentifierInterface extends ResourceIdentifierInterface {
+
+	/** The service segment (e.g. "account1") */
+	public function service(): string;
+
+}