diff --git a/example-config.yaml b/example-config.yaml
index 167fda4b..5d855afd 100644
--- a/example-config.yaml
+++ b/example-config.yaml
@@ -17,6 +17,9 @@ appservice:
     # The hostname and port where this appservice should listen.
     hostname: 0.0.0.0
     port: 8080
+    # The maximum body size of appservice API requests (from the homeserver) in mebibytes
+    # Usually 1 is enough, but on high-traffic bridges you might need to increase this to avoid 413s
+    max_body_size: 1
 
     # The full URI to the database. SQLite and Postgres are fully supported.
     # Other DBMSes supported by SQLAlchemy may or may not work.
diff --git a/mautrix_telegram/__main__.py b/mautrix_telegram/__main__.py
index b1768a8f..b2e2064b 100644
--- a/mautrix_telegram/__main__.py
+++ b/mautrix_telegram/__main__.py
@@ -86,7 +86,8 @@ appserv = AppService(config["homeserver.address"], config["homeserver.domain"],
                      config["appservice.as_token"], config["appservice.hs_token"],
                      config["appservice.bot_username"], log="mau.as", loop=loop,
                      verify_ssl=config["homeserver.verify_ssl"], state_store=state_store,
-                     real_user_content_key="net.maunium.telegram.puppet")
+                     real_user_content_key="net.maunium.telegram.puppet",
+                     aiohttp_params={"client_max_size": config["appservice.max_body_size"]})
 
 context = Context(appserv, db_session, config, loop, session_container)
 
@@ -101,7 +102,6 @@ if config["appservice.provisioning.enabled"]:
                            provisioning_api.app)
     context.provisioning_api = provisioning_api
 
-
 with appserv.run(config["appservice.hostname"], config["appservice.port"]) as start:
     init_db(db_session)
     init_abstract_user(context)
diff --git a/mautrix_telegram/config.py b/mautrix_telegram/config.py
index 122e49d8..15da6cfa 100644
--- a/mautrix_telegram/config.py
+++ b/mautrix_telegram/config.py
@@ -153,6 +153,7 @@ class Config(DictWithRecursion):
             copy("appservice.address")
         copy("appservice.hostname")
         copy("appservice.port")
+        copy("appservice.max_body_size")
 
         copy("appservice.database")