diff --git a/relay/actor.py b/relay/actor.py
index b2117fd..7eefab7 100644
--- a/relay/actor.py
+++ b/relay/actor.py
@@ -30,6 +30,7 @@ if "actorKeys" not in DATABASE:
 PRIVKEY = RSA.importKey(DATABASE["actorKeys"]["privateKey"])
 PUBKEY = PRIVKEY.publickey()
 
+sem = asyncio.Semaphore(500)
 
 from . import app, CONFIG
 from .remote_actor import fetch_actor
@@ -77,7 +78,6 @@ get_actor_inbox = lambda actor: actor.get('endpoints', {}).get('sharedInbox', ac
 
 async def push_message_to_actor(actor, message, our_key_id):
     inbox = get_actor_inbox(actor)
-
     url = urlsplit(inbox)
 
     # XXX: Digest
@@ -93,15 +93,17 @@ async def push_message_to_actor(actor, message, our_key_id):
 
     logging.debug('%r >> %r', inbox, message)
 
-    try:
-        async with aiohttp.ClientSession(trace_configs=[http_debug()]) as session:
-            async with session.post(inbox, data=data, headers=headers) as resp:
-                if resp.status == 202:
-                    return
-                resp_payload = await resp.text()
-                logging.debug('%r >> resp %r', inbox, resp_payload)
-    except Exception as e:
-        logging.info('Caught %r while pushing to %r.', e, inbox)
+    global sem
+    async with sem:
+        try:
+            async with aiohttp.ClientSession(trace_configs=[http_debug()]) as session:
+                async with session.post(inbox, data=data, headers=headers) as resp:
+                    if resp.status == 202:
+                        return
+                    resp_payload = await resp.text()
+                    logging.debug('%r >> resp %r', inbox, resp_payload)
+        except Exception as e:
+            logging.info('Caught %r while pushing to %r.', e, inbox)
 
 
 async def follow_remote_actor(actor_uri):
@@ -308,5 +310,4 @@ async def inbox(request):
 
     return aiohttp.web.Response(body=b'{}', content_type='application/activity+json')
 
-
 app.router.add_post('/inbox', inbox)