diff --git a/py2http/default_configs.py b/py2http/default_configs.py
index f95bd89..52369ee 100644
--- a/py2http/default_configs.py
+++ b/py2http/default_configs.py
@@ -255,6 +255,9 @@ def framework_defaults(framework, *, error_handler, output_mapper):
     "logger": None,
     "plugins": [],
     "enable_cors": False,
+    # Bottle only: max bytes of an in-memory request body (None keeps bottle's 100 KiB).
+    # A bigger request is answered "413 Request entity too large".
+    "max_request_size": None,
     "cors_allowed_origins": "*",
     "publish_openapi": False,
     "openapi_insecure": False,
diff --git a/py2http/service.py b/py2http/service.py
index 0024f9d..7ff198d 100644
--- a/py2http/service.py
+++ b/py2http/service.py
@@ -371,6 +371,11 @@ def mk_bottle_app(funcs, **configs):
     configs = dict(configs, framework=BOTTLE)
     routes, openapi_spec = mk_routes_and_openapi_specs(funcs, **configs)
     app = Bottle(catchall=False)
+    max_request_size = mk_config("max_request_size", None, configs, default_configs)
+    if max_request_size is not None:
+        from bottle import BaseRequest
+
+        BaseRequest.MEMFILE_MAX = int(max_request_size)  # bottle: process-wide
     enable_cors = mk_config("enable_cors", None, configs, default_configs)
     plugins = mk_config("plugins", None, configs, default_configs)
     if enable_cors:
diff --git a/py2http/tests/test_max_request_size.py b/py2http/tests/test_max_request_size.py
new file mode 100644
index 0000000..1979532
--- /dev/null
+++ b/py2http/tests/test_max_request_size.py
@@ -0,0 +1,27 @@
+"""``max_request_size`` raises bottle's in-memory body limit (i2mint/py2http#4)."""
+
+import pytest
+
+pytest.importorskip("bottle")
+from bottle import BaseRequest
+
+from py2http import mk_app
+
+
+def echo(x: str):
+    return x
+
+
+def test_max_request_size_sets_bottle_limit():
+    original = BaseRequest.MEMFILE_MAX
+    try:
+        mk_app([echo], framework="bottle", max_request_size=5_000_000)
+        assert BaseRequest.MEMFILE_MAX == 5_000_000
+    finally:
+        BaseRequest.MEMFILE_MAX = original
+
+
+def test_default_leaves_bottle_limit_alone():
+    original = BaseRequest.MEMFILE_MAX
+    mk_app([echo], framework="bottle")
+    assert BaseRequest.MEMFILE_MAX == original