diff --git a/backend/handlers/cardstags.go b/backend/handlers/cardstags.go
index 1079368..eb66729 100644
--- a/backend/handlers/cardstags.go
+++ b/backend/handlers/cardstags.go
@@ -78,8 +78,9 @@ func CreateCardTag(c *fiber.Ctx) error {
 	}
 
 	publish(fiber.Map{
-		"object": "cardtag",
+		"object": "cardTag",
 		"action": "create",
+		"card_id": cardID,
 		"data": cardtag,
 		"X-Request-Source": source,
 	});
@@ -172,9 +173,10 @@ func DeleteCardTag(c *fiber.Ctx) error {
 	}
 
 	publish(fiber.Map{
-		"object": "cardtag",
+		"object": "cardTag",
 		"action": "delete",
-		"id": cardID,
+		"card_id": cardID,
+		"tag_id": tagID,
 		"X-Request-Source": source,
 	});
 
@@ -272,7 +274,7 @@ func UpdateCardTag(c *fiber.Ctx) error {
 	}
 
 	publish(fiber.Map{
-		"object": "cardtag",
+		"object": "cardTag",
 		"action": "update",
 		"card_id": cardID,
 		"tag_id": tagID,
diff --git a/backend/handlers/tags.go b/backend/handlers/tags.go
index 3b0653e..a7807cc 100644
--- a/backend/handlers/tags.go
+++ b/backend/handlers/tags.go
@@ -48,7 +48,7 @@ func CreateTag(c *fiber.Ctx) error {
 	}
 
 	publish(fiber.Map{
-		"object": "tag",
+		"object": "projectTag",
 		"action": "create",
 		"data": tag,
 		"X-Request-Source": source,
@@ -106,7 +106,7 @@ func DeleteTag(c *fiber.Ctx) error {
 	}
 
 	publish(fiber.Map{
-		"object": "tag",
+		"object": "projectTag",
 		"action": "delete",
 		"id": id,
 		"X-Request-Source": source,
@@ -149,7 +149,7 @@ func UpdateTag(c *fiber.Ctx) error {
 	}
 
 	publish(fiber.Map{
-		"object": "tag",
+		"object": "projectTag",
 		"action": "update",
 		"id": id,
 		"changes": tag,
@@ -202,7 +202,7 @@ func CreateTagOption(c *fiber.Ctx) error {
 	}
 
 	publish(fiber.Map{
-		"object": "tagoption",
+		"object": "tagOption",
 		"action": "create",
 		"data": option,
 		"X-Request-Source": source,
@@ -284,7 +284,7 @@ func DeleteTagOption(c *fiber.Ctx) error {
 	}
 
 	publish(fiber.Map{
-		"object": "tagoption",
+		"object": "tagOption",
 		"action": "delete",
 		"tag_id": tagID,
 		"option_id": optionID,
@@ -344,7 +344,7 @@ func UpdateTagOption(c *fiber.Ctx) error {
 	}
 
 	publish(fiber.Map{
-		"object": "tagoption",
+		"object": "tagOption",
 		"action": "update",
 		"tag_id": tagID,
 		"option_id": optionID,
diff --git a/frontend/src/lib/types/Card.ts b/frontend/src/lib/types/Card.ts
index 8608e7b..5c03b30 100644
--- a/frontend/src/lib/types/Card.ts
+++ b/frontend/src/lib/types/Card.ts
@@ -152,7 +152,7 @@ export default class Card {
 		return true;
 	}
 
-	updateFromDict(dict: any) {
+	parseUpdate(dict: any) {
 		if (dict.project_id && dict.project_id !== this._project.id) {
 			this._project = Project.fromId(dict.project_id) as Project;
 		}
@@ -160,6 +160,31 @@ export default class Card {
 		if (dict.content) this._content = dict.content;
 	}
 
+	static parseDelete(id: any) {
+		cards.update((cards) => cards.filter((c) => c.id !== id));
+	}
+
+	parseTag(dict: any) {
+		const cardTag = CardTag.parse(dict, this);
+		if (!cardTag) return;
+
+		this._cardTags = [...this._cardTags, cardTag];
+	}
+
+	parseTagUpdate(dict: any) {
+		const cardTag = this._cardTags.find((ct) => ct.projectTag.id === dict.tag_id);
+		if (!cardTag) {
+			toastAlert('Failed to parse card tag update: card tag not found');
+			return;
+		}
+
+		cardTag.parseUpdate(dict);
+	}
+
+	parseTagDelete(id: any) {
+		this._cardTags = this._cardTags.filter((ct) => ct.projectTag.id !== id);
+	}
+
 	static parse(json: any): Card | null;
 	static parse(json: any, project: Project | null | undefined): Card | null;
 
diff --git a/frontend/src/lib/types/CardTag.ts b/frontend/src/lib/types/CardTag.ts
index 10be45f..4680369 100644
--- a/frontend/src/lib/types/CardTag.ts
+++ b/frontend/src/lib/types/CardTag.ts
@@ -71,6 +71,35 @@ export default class CardTag {
 		return true;
 	}
 
+	parseUpdate(dict: any) {
+		if (dict.card_id && dict.card_id !== this._card.id) {
+			toastAlert('Failed to parse card tag update: card id mismatch');
+			return;
+		}
+
+		if (dict.tag_id && dict.tag_id !== this._projectTag.id) {
+			toastAlert('Failed to parse card tag update: projectTag id mismatch');
+			return;
+		}
+
+		if (dict.option_id) {
+			const option = this._projectTag.options.find((option) => option.id === dict.option_id);
+			if (!option) {
+				toastAlert('Failed to parse card tag update: option not found');
+				return;
+			}
+			this._option = option;
+		} else if (this._option) {
+			this._option = null;
+		}
+
+		if (dict.value) {
+			this._value = dict.value;
+		} else if (this._value) {
+			this._value = null;
+		}
+	}
+
 	static parse(json: any): CardTag | null;
 	static parse(json: any, card: Card | null | undefined): CardTag | null;
 
diff --git a/frontend/src/lib/types/Project.ts b/frontend/src/lib/types/Project.ts
index 0068997..9eac673 100644
--- a/frontend/src/lib/types/Project.ts
+++ b/frontend/src/lib/types/Project.ts
@@ -65,10 +65,14 @@ export default class Project {
 		return true;
 	}
 
-	updateFromDict(dict: any) {
+	parseUpdate(dict: any) {
 		if (dict.title) this._title = dict.title;
 	}
 
+	static parseDelete(id: any) {
+		projects.update((projects) => projects.filter((project) => project.id !== id));
+	}
+
 	static parse(json: any): Project | null {
 		if (!json) return null;
 
diff --git a/frontend/src/lib/utils/webSocketManager.ts b/frontend/src/lib/utils/webSocketManager.ts
index 96d81ea..7dcf8ec 100644
--- a/frontend/src/lib/utils/webSocketManager.ts
+++ b/frontend/src/lib/utils/webSocketManager.ts
@@ -1,4 +1,5 @@
 import Card, { cards } from '$lib/types/Card';
+import CardTag from '$lib/types/CardTag';
 import Project, { projects } from '$lib/types/Project';
 import ProjectTag, { projectTags } from '$lib/types/ProjectTag';
 import View, { views } from '$lib/types/View';
@@ -78,77 +79,99 @@ export default class WebSocketManager {
 }
 
 function applyMessage(data: any) {
-	switch (data.object) {
-		case 'project':
-			applyProject(data);
-			break;
-		case 'card':
-			applyCard(data);
-			break;
-		case 'view':
-			applyView(data);
-			break;
-		case 'projectTag':
-			applyProjectTag(data);
-			break;
-		default:
-			console.log('Unknown object:', data);
+	console.debug('WebSocket message:', data);
+	if (!data.object) {
+		toastWarning('Failed to parse WebSocket message: missing object');
+		return;
 	}
+
+	if (!data.action) {
+		toastWarning('Failed to parse WebSocket message: missing action');
+		return;
+	}
+
+	if (data.object === 'project') applyProject(data);
+	else if (data.object === 'cardTag') applyCardTag(data);
+	else if (data.object === 'card') applyCard(data);
+	else if (data.object === 'view') applyView(data);
+	else if (data.object === 'projectTag') applyProjectTag(data);
+	else if (data.object === 'filter') applyFilter(data);
+	else toastWarning('Failed to parse WebSocket message: unknown object');
 }
 
 function applyProject(data: any) {
-	switch (data.action) {
-		case 'create':
-			Project.parse(data.data);
-		case 'update':
-			get(projects)
-				.find((p) => p.id === data.id)
-				?.updateFromDict(data.changes);
-			projects.reload();
-			break;
-		case 'delete':
-			projects.set(get(projects).filter((p) => p.id !== data.id));
-			break;
+	if (data.action === 'create') {
+		Project.parse(data.data);
+		return;
 	}
+	if (data.action === 'delete') {
+		Project.parseDelete(data.id);
+		return;
+	}
+
+	const project = Project.fromId(data.id);
+	if (!project) {
+		toastWarning('Failed to parse project update: project not found');
+		return;
+	}
+
+	if (data.action !== 'update') {
+		toastWarning('Failed to parse project update: unknown action');
+		return;
+	}
+
+	project.parseUpdate(data.changes);
+	projects.reload();
 }
 
 function applyCard(data: any) {
-	switch (data.action) {
-		case 'create':
-			Card.parse(data.data);
-			break;
-		case 'update':
-			get(cards)
-				.find((c) => c.id === data.id)
-				?.updateFromDict(data.changes);
-			cards.reload();
-			break;
-		case 'delete':
-			cards.set(get(cards).filter((c) => c.id !== data.id));
-			break;
+	if (data.action === 'create') {
+		Card.parse(data.data);
+		return;
 	}
+	if (data.action === 'delete') {
+		Card.parseDelete(data.id);
+		return;
+	}
+
+	const card = Card.fromId(data.id);
+	if (!card) {
+		toastWarning('Failed to parse card update: card not found');
+		return;
+	}
+
+	if (data.action !== 'update') {
+		toastWarning('Failed to parse card update: unknown action');
+		return;
+	}
+
+	card.parseUpdate(data.changes);
+	cards.reload();
 }
 
-function applyView(data: any) {
-	switch (data.action) {
-		case 'create':
-		case 'update':
-			View.parse(data.value);
-			break;
-		case 'delete':
-			views.set(get(views).filter((v) => v.id !== data.id));
-			break;
+function applyCardTag(data: any) {
+	const card = Card.fromId(data.card_id);
+	if (!card) {
+		toastWarning('Failed to parse card tag update: card not found');
+		return;
 	}
+
+	if (data.action === 'create') {
+		card.parseTag(data.data);
+	} else if (data.action === 'update') {
+		card.parseTagUpdate(data.changes);
+	} else if (data.action === 'delete') {
+		card.parseTagDelete(data.tag_id);
+	} else {
+		toastWarning('Failed to parse card tag update: unknown action');
+		return;
+	}
+
+	cards.reload();
 }
 
-function applyProjectTag(data: any) {
-	switch (data.action) {
-		case 'create':
-		case 'update':
-			ProjectTag.parse(data.value);
-			break;
-		case 'delete':
-			projectTags.set(get(projectTags).filter((t) => t.id !== data.id));
-			break;
-	}
-}
+function applyView(data: any) {}
+
+function applyProjectTag(data: any) {}
+
+function applyFilter(data: any) {}