diff --git a/README.md b/README.md
index d962de2..ba8afd5 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ services:
 - You will need these dependencies:
 
   ```sh
-  $ opam install cohttp-lwt-unix tls-lwt dotenv twostep lwt_ssl yojson
+  $ opam install cohttp-lwt-unix tls-lwt dotenv twostep lwt_ssl yojson core
   ```
 
 - Populate your credentials in [config/.env](./config/.env)