diff --git a/mautrix/api.py b/mautrix/api.py
index d034149b..b8ee2897 100644
--- a/mautrix/api.py
+++ b/mautrix/api.py
@@ -16,7 +16,7 @@
 import platform
 import time
 
-from aiohttp import ClientResponse, ClientSession, __version__ as aiohttp_version
+from aiohttp import ClientResponse, ClientSession, UnixConnector, __version__ as aiohttp_version
 from aiohttp.client_exceptions import ClientError, ContentTypeError
 from yarl import URL
 
@@ -229,9 +229,15 @@ def __init__(
         self.base_url = URL(base_url)
         self.token = token
         self.log = log or logging.getLogger("mau.http")
-        self.session = client_session or ClientSession(
-            loop=loop, headers={"User-Agent": self.default_ua}
-        )
+        if client_session:
+            self.session = client_session
+        else:
+            connector = None
+            if base_url.startswith("unix://"):
+                connector = UnixConnector(path=base_url.replace("unix://", ""))
+            self.session = ClientSession(
+                loop=loop, headers={"User-Agent": self.default_ua}, connector=connector
+            )
         self.as_user_id = as_user_id
         self.as_device_id = as_device_id
         if txn_id is not None:
diff --git a/mautrix/appservice/appservice.py b/mautrix/appservice/appservice.py
index 892db195..c877e942 100644
--- a/mautrix/appservice/appservice.py
+++ b/mautrix/appservice/appservice.py
@@ -152,7 +152,11 @@ async def __aexit__(self) -> None:
     async def start(self, host: str = "127.0.0.1", port: int = 8080) -> None:
         await self.state_store.open()
         self.log.debug(f"Starting appservice web server on {host}:{port}")
-        if self.server.startswith("https://") and not self.verify_ssl:
+        if self.server.startswith("unix://"):
+            path = self.server.replace("unix://", "")
+            self.server = "http://localhost"
+            connector = aiohttp.UnixConnector(limit=self.connection_limit, path=path)
+        elif self.server.startswith("https://") and not self.verify_ssl:
             connector = aiohttp.TCPConnector(limit=self.connection_limit, verify_ssl=False)
         else:
             connector = aiohttp.TCPConnector(limit=self.connection_limit)
@@ -176,7 +180,10 @@ async def start(self, host: str = "127.0.0.1", port: int = 8080) -> None:
             ssl_ctx.load_cert_chain(self.tls_cert, self.tls_key)
         self.runner = web.AppRunner(self.app)
         await self.runner.setup()
-        site = web.TCPSite(self.runner, host, port, ssl_context=ssl_ctx)
+        if host.startswith("/"):
+            site = web.UnixSite(self.runner, host)
+        else:
+            site = web.TCPSite(self.runner, host, port, ssl_context=ssl_ctx)
         await site.start()
 
     async def stop(self) -> None: