diff --git a/docs/index.rst b/docs/index.rst
index 00f3871b..5450ea5c 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -67,6 +67,7 @@ Development documentation
     :maxdepth: 3
 
     development
+    extensiondev
 
 
 Indices and tables
diff --git a/extensiondev.rst b/extensiondev.rst
new file mode 100644
index 00000000..7fe5a2f4
--- /dev/null
+++ b/extensiondev.rst
@@ -0,0 +1,22 @@
+*********************
+Extension development
+*********************
+
+.. warning:: Draft
+
+    This document is a draft open for discussion. It shows how we imagine that
+    development of Mopidy extensions should become in the future, not how to
+    currently develop an extension for Mopidy.
+
+An extension wants to:
+
+- Be automatically found if installed
+- Provide default config
+- Validate configuration
+- Validate presence of dependencies
+  - Python packages (e.g. pyspotify)
+  - Other software
+  - Other extensions (e.g. SoundCloud depends on stream backend)
+- Validate that needed TCP ports are free
+- Be asked to start running
+- Be asked to shut down