Document mitmweb architecture
diff --git a/web/README.md b/web/README.md
index ae558bd6e6..7b412a5f1b 100644
--- a/web/README.md
+++ b/web/README.md
@@ -6,3 +6,11 @@ and activate your virtualenv environment before proceeding.**
 - Run `yarn` to install dependencies
 - Run `yarn run gulp` to start live-compilation.
 - Run `mitmweb` and open http://localhost:8081/
+
+## Architecture
+
+There are two components:
+
+- Server: [`mitmproxy/tools/web`](../mitmproxy/tools/web)
+
+- Client: `web`

Bug: https://github.com/mitmproxy/mitmproxy/issues/3925