diff --git a/.env.example b/.env.example
new file mode 100644
index 000000000..9a37d7e3e
--- /dev/null
+++ b/.env.example
@@ -0,0 +1,5 @@
+HEYGEN_API_KEY="your Heygen API key"
+NEXT_PUBLIC_BASE_API_URL=https://api.heygen.com
+# Optional OpenAI integration keys
+OPENAI_API_KEY="your OpenAI API key"
+NEXT_PUBLIC_OPENAI_API_KEY="your OpenAI API key"
diff --git a/README.md b/README.md
index b647533a3..2e1cf64af 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,15 @@ Feel free to play around with the existing code and please leave any feedback fo
 
 6. Run `npm run dev`
 
+### Environment variables
+
+Copy `.env.example` to `.env` and fill in your credentials. The demo understands the following keys:
+
+- `HEYGEN_API_KEY` – used by `app/api/get-access-token/route.ts` to request streaming tokens.
+- `NEXT_PUBLIC_BASE_API_URL` – base URL for HeyGen's API (`https://api.heygen.com` by default).
+- `OPENAI_API_KEY` – optional key for sample OpenAI integrations.
+- `NEXT_PUBLIC_OPENAI_API_KEY` – optional client-side key for OpenAI demos.
+
 ### Starting sessions
 
 NOTE: Make sure you have enter your token into the `.env` file and run `npm run dev`.