diff --git a/pyproject.toml b/pyproject.toml
index 65a08b9..6f06de0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,6 +24,7 @@ dependencies = [
 	"barkshark-sql == 0.1.4-1",
 	"click >= 8.1.2",
 	"hiredis == 2.3.2",
+	"idna == 3.4",
 	"jinja2-haml == 0.3.5",
 	"markdown == 3.6",
 	"platformdirs == 4.2.2",
diff --git a/relay/frontend/page/admin-domain_bans.haml b/relay/frontend/page/admin-domain_bans.haml
index 19ae4ae..b1f7f57 100644
--- a/relay/frontend/page/admin-domain_bans.haml
+++ b/relay/frontend/page/admin-domain_bans.haml
@@ -35,7 +35,7 @@
 						%tr(id="{{ban.domain}}")
 							%td.domain
 								%details
-									%summary -> =ban.domain
+									%summary -> =ban.domain.encode().decode("idna")
 
 									.grid-2col
 										%label.reason(for="{{ban.domain}}-reason") << Reason
diff --git a/relay/frontend/page/admin-instances.haml b/relay/frontend/page/admin-instances.haml
index 2e43f48..c317e30 100644
--- a/relay/frontend/page/admin-instances.haml
+++ b/relay/frontend/page/admin-instances.haml
@@ -39,7 +39,7 @@
 						-for request in requests
 							%tr(id="{{request.domain}}")
 								%td.instance
-									%a(href="https://{{request.domain}}" target="_new") -> =request.domain
+									%a(href="https://{{request.domain}}" target="_new") -> =request.domain.encode().decode("idna")
 
 								%td.software
 									=request.software or "n/a"
@@ -69,7 +69,7 @@
 					-for instance in instances
 						%tr(id="{{instance.domain}}")
 							%td.instance
-								%a(href="https://{{instance.domain}}/" target="_new") -> =instance.domain
+								%a(href="https://{{instance.domain}}/" target="_new") -> =instance.domain.encode().decode("idna")
 
 							%td.software
 								=instance.software or "n/a"
diff --git a/relay/frontend/page/admin-whitelist.haml b/relay/frontend/page/admin-whitelist.haml
index f494aef..c8111e5 100644
--- a/relay/frontend/page/admin-whitelist.haml
+++ b/relay/frontend/page/admin-whitelist.haml
@@ -27,7 +27,7 @@
 				-for item in whitelist
 					%tr(id="{{item.domain}}")
 						%td.domain
-							=item.domain
+							=item.domain.encode().decode("idna")
 
 						%td.date
 							=item.created.strftime("%Y-%m-%d")
diff --git a/relay/frontend/page/home.haml b/relay/frontend/page/home.haml
index f9618fc..fa883d6 100644
--- a/relay/frontend/page/home.haml
+++ b/relay/frontend/page/home.haml
@@ -41,7 +41,7 @@
 					-for instance in instances
 						%tr
 							%td.instance -> %a(href="https://{{instance.domain}}/" target="_new")
-								=instance.domain
+								=instance.domain.encode().decode("idna")
 
 							%td.date
 								=instance.created.strftime("%Y-%m-%d")
diff --git a/relay/views/api.py b/relay/views/api.py
index 86382f4..70a9f0e 100644
--- a/relay/views/api.py
+++ b/relay/views/api.py
@@ -203,6 +203,8 @@ class Inbox(View):
 			if conn.get_inbox(data['domain']):
 				return Response.new_error(404, 'Instance already in database', 'json')
 
+			data['domain'] = data['domain'].encode('idna').decode()
+
 			if not data.get('inbox'):
 				actor_data: Message | None = await self.client.get(data['actor'], True, Message)
 
@@ -229,6 +231,8 @@ class Inbox(View):
 			if isinstance(data, Response):
 				return data
 
+			data['domain'] = data['domain'].encode('idna').decode()
+
 			if not (instance := conn.get_inbox(data['domain'])):
 				return Response.new_error(404, 'Instance with domain not found', 'json')
 
@@ -244,6 +248,8 @@ class Inbox(View):
 			if isinstance(data, Response):
 				return data
 
+			data['domain'] = data['domain'].encode('idna').decode()
+
 			if not conn.get_inbox(data['domain']):
 				return Response.new_error(404, 'Instance with domain not found', 'json')
 
@@ -263,7 +269,12 @@ class RequestView(View):
 
 	async def post(self, request: Request) -> Response:
 		data: dict[str, Any] | Response = await self.get_api_data(['domain', 'accept'], [])
+
+		if isinstance(data, Response):
+			return data
+
 		data['accept'] = boolean(data['accept'])
+		data['domain'] = data['domain'].encode('idna').decode()
 
 		try:
 			with self.database.session(True) as conn:
@@ -308,6 +319,8 @@ class DomainBan(View):
 		if isinstance(data, Response):
 			return data
 
+		data['domain'] = data['domain'].encode('idna').decode()
+
 		with self.database.session() as conn:
 			if conn.get_domain_ban(data['domain']):
 				return Response.new_error(400, 'Domain already banned', 'json')
@@ -324,6 +337,8 @@ class DomainBan(View):
 			if isinstance(data, Response):
 				return data
 
+			data['domain'] = data['domain'].encode('idna').decode()
+
 			if not conn.get_domain_ban(data['domain']):
 				return Response.new_error(404, 'Domain not banned', 'json')
 
@@ -342,6 +357,8 @@ class DomainBan(View):
 			if isinstance(data, Response):
 				return data
 
+			data['domain'] = data['domain'].encode('idna').decode()
+
 			if not conn.get_domain_ban(data['domain']):
 				return Response.new_error(404, 'Domain not banned', 'json')
 
@@ -479,6 +496,8 @@ class Whitelist(View):
 		if isinstance(data, Response):
 			return data
 
+		data['domain'] = data['domain'].encode('idna').decode()
+
 		with self.database.session() as conn:
 			if conn.get_domain_whitelist(data['domain']):
 				return Response.new_error(400, 'Domain already added to whitelist', 'json')
@@ -494,6 +513,8 @@ class Whitelist(View):
 		if isinstance(data, Response):
 			return data
 
+		data['domain'] = data['domain'].encode('idna').decode()
+
 		with self.database.session() as conn:
 			if not conn.get_domain_whitelist(data['domain']):
 				return Response.new_error(404, 'Domain not in whitelist', 'json')