Every node, created with Ockam Command, starts a secure channel listener at address /service/api. Let's create a secure channel between two nodes and send a message from one node to another.
```sh
$ ockam node create a
$ ockam node create b
$ ockam secure-channel create --from a --to /node/b/service/api
Created Secure Channel:
• From: /node/a
• To: /node/b/service/api (/ip4/127.0.0.1/tcp/53483/service/api)
• At: /service/d92ef0aea946ec01cdbccc5b9d3f2e16
$ ockam message send hello --from a --to /service/d92ef0aea946ec01cdbccc5b9d3f2e16/service/uppercase
HELLO
```