Most API actions require an access token, which you must generate yourself once and store it safely. Access token must be supplied to VertexSMS API through HTTP headers. Header name: X-VertexSMS-Token you will see it in all examples.
Or as an alternative way you can pass the access token via query string at parameter.
You can generate access token via VertexSMS page, login to your account and then go to “MY ACCOUNT” ->”API”
Currently there are support only for one access token at the time, we are working for supporting multiple access tokens with different permissions and IP access blocking.