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+Memory usage
+============
+
+.. currentmodule:: websockets
+
+In most cases, memory usage of a WebSocket server is proportional to the
+number of open connections. When a server handles thousands of connections,
+memory usage can become a bottleneck.
+
+Memory usage of a single connection is the sum of:
+
+1. the baseline amount of memory websockets requires for each connection,
+2. the amount of data held in buffers before the application processes it,
+3. any additional memory allocated by the application itself.
+
+Baseline
+--------
+
+Compression settings are the main factor affecting the baseline amount of
+memory used by each connection.
+
+With websockets' defaults, on the server side, a single connections uses
+70 KiB of memory.
+
+Refer to the :doc:`topic guide on compression <../topics/compression>` to
+learn more about tuning compression settings.
+
+Buffers
+-------
+
+Under normal circumstances, buffers are almost always empty.
+
+Under high load, if a server receives more messages than it can process,
+bufferbloat can result in excessive memory usage.
+
+By default websockets has generous limits. It is strongly recommended to adapt
+them to your application. When you call :func:`~server.serve`:
+
+- Set ``max_size`` (default: 1 MiB, UTF-8 encoded) to the maximum size of
+  messages your application generates.
+- Set ``max_queue`` (default: 32) to the maximum number of messages your
+  application expects to receive faster than it can process them. The queue
+  provides burst tolerance without slowing down the TCP connection.
+
+Furthermore, you can lower ``read_limit`` and ``write_limit`` (default:
+64 KiB) to reduce the size of buffers for incoming and outgoing data.
+
+The design document provides :ref:`more details about buffers <buffers>`.