If you are a curious entity you can use either path. This captcha is here to ensure the interface is efficient, not to keep entities boxes.
$token = "<access_token>";
Invoke-RestMethod -Uri "http://127.0.0.1:8080/api/v1/echo" `
-Method Post `
-Headers @{ Authorization = "Bearer $token" } `
-ContentType "application/json" `
-Body '{"payload":"hello from PS"}'