diff --git a/README.md b/README.md
index 6cdb236..6f756d6 100644
--- a/README.md
+++ b/README.md
@@ -25,3 +25,8 @@ src/
 ## Environment variables
 
 Copy `.env.example` to `.env.local` for local development.
+
+## Feature flags
+
+Runtime feature flags are controlled via `VITE_FLAGS_*` env vars.
+See `src/utils/flags.ts` for usage.