IonQ's API gives access to IonQ's trapped ion quantum computers as well as a cloud simulator. IonQ direct access is currently restricted to those with access to an IonQ API key. As of January 2021, this access is currently restricted to partners. More information about partnerships can be found at ionq.com/get-started.
Authentication
To use Cirq with the IonQ API, one needs an API key. This is a random looking string.
Given that you have the API key, there are two ways to use these to
get an object in python to access the API. The object that you construct to access
the API are instances of the cirq_ionq.Service class. You can directly use the API key in constructing this instances of this class. Here is an example of this pattern:
import cirq_ionq as ionq
service = ionq.Service(api_key='tomyheart')
Alternatively, you can use environment variables to set this value. These environment variable for the api key is IONQ_API_KEY. Details of how to set environment variables vary by operating system. For example in bash, you would do
export IONQ_API_KEY=tomyheart
In the case that you have set these environment variables, you can just perform
import cirq_ionq as ionq
service = ionq.Service()
The advantage of doing things this way is that you do not have to store the API key in source code, which might accidentally get uploaded to a version control system, and hence leak the API key.
Next steps
Learn how to run jobs against the service