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
✔ Secure Channel at /service/a2b1a2275d02308a7920499b5f49e4ee created successfully
From /node/n1 to /node/n2/service/api
$ ockam message send hello --from a --to /service/d92ef0aea946ec01cdbccc5b9d3f2e16/service/uppercase
HELLO
```