diff --git a/config/runtime.exs b/config/runtime.exs
index a5a93fa..7da64c4 100644
--- a/config/runtime.exs
+++ b/config/runtime.exs
@@ -38,8 +38,8 @@ if config_env() == :prod do
 
   config :claper, ClaperWeb.Endpoint,
     url: [
-      host: System.get_env("ENDPOINT_HOST"),
-      port: 80
+      host: System.get_env("ENDPOINT_HOST", "localhost"),
+      port:  System.get_env("ENDPOINT_PORT", 80)
     ],
     http: [
       # Enable IPv6 and bind on all interfaces.
diff --git a/docker-compose.yml b/docker-compose.yml
index 89b5e5d..f4d47e3 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -16,5 +16,6 @@ services:
       DATABASE_URL: postgres://claper:claper@db:5432/claper
       SECRET_KEY_BASE: 0LZiQBLw4WvqPlz4cz8RsHJlxNiSqM9B48y4ChyJ5v1oA0L/TPIqRjQNdPZN3iEG
       MAIL_TRANSPORT: local
+      ENDPOINT_PORT: 4000
     depends_on:
       - db
\ No newline at end of file
diff --git a/guides/introduction/configuration.md b/guides/introduction/configuration.md
index 12acfa7..ab5780f 100644
--- a/guides/introduction/configuration.md
+++ b/guides/introduction/configuration.md
@@ -29,4 +29,7 @@ You can use all local variables plus the following:
 Variable | Values | Default | Required | Description
 --- | --- | --- | --- | ---
 DATABASE_URL | - | - | ✓ | Postgres connection string
-SECRET_KEY_BASE | - | - |  ✓ |  Generate it with `mix phx.gen.secret`
\ No newline at end of file
+SECRET_KEY_BASE | - | - |  ✓ |  Generate it with `mix phx.gen.secret`
+ENDPOINT_HOST | - | localhost |  - | Host used to access the app (used for url generation)
+ENDPOINT_PORT | - | 80 |  - | Port used to access the app (used for url generation)
+PORT | - | 4000 |  - | Port to listen to
\ No newline at end of file