diff --git a/cli/Cargo.toml b/cli/Cargo.toml
index 19947599..3f7b080f 100644
--- a/cli/Cargo.toml
+++ b/cli/Cargo.toml
@@ -28,7 +28,7 @@ rand = { workspace = true }
 
 # CLI specific dependencies
 magic-wormhole = { path = "..", version = "0.7", features = ["all", "entropy"] }
-clap = { workspace = true, features = ["cargo", "derive", "help"] }
+clap = { workspace = true, features = ["cargo", "derive", "help", "env"] }
 clap_complete = { workspace = true }
 env_logger = { workspace = true }
 console = { workspace = true }
diff --git a/cli/src/main.rs b/cli/src/main.rs
index c15aeba7..7653e33f 100644
--- a/cli/src/main.rs
+++ b/cli/src/main.rs
@@ -120,10 +120,11 @@ struct CommonArgs {
         action = clap::ArgAction::Append,
         value_name = "tcp://HOSTNAME:PORT",
         value_hint = clap::ValueHint::Url,
+        env = "WORMHOLE_RELAY_URL",
     )]
     relay_server: Vec<url::Url>,
     /// Use a custom rendezvous server. Both sides need to use the same value in order to find each other.
-    #[arg(long, value_name = "ws://example.org", value_hint = clap::ValueHint::Url)]
+    #[arg(long, value_name = "ws://example.org", value_hint = clap::ValueHint::Url, env = "WORMHOLE_MAILBOX_URL")]
     rendezvous_server: Option<url::Url>,
     /// Disable the relay server support and force a direct connection.
     #[arg(long)]