This is a simple node service that listens for transactions to a specific address and then simply sends a payment back to the sender with the amount of amount - fee. The fee can be configured but by default is set to 5.
First you'll need to have a coda daemon running on your machine. See the docs here for instructions on getting a node, then run the following command:
$ coda daemon -rest-port 49370 -peer beta.o1test.net:8303
This process must be running for this service to work. Open a new terminal session before you continue.
The service requires node to be installed on your system, and uses yarn as the package manager. Here's how you run the echo service:
$ yarn
$ yarn start
Look at the logs for the address on which the service is listening. When you send a payment to the service, it will send back a payment with the amount equal to initial_amount - fee which can be configured, however is set to 5 by default.