Amazon Cognito introduces pricing for machine-to-machine (M2M) authentication to better support continued growth and expand capabilities. There is no change to Amazon Cognito’s user based pricing (monthly active users or MAUs). Customer accounts currently using Amazon Cognito for M2M use cases will be exempt from pricing for 12 months. M2M pricing is based on the number of application clients configured for M2M authentication and the number of tokens requested for them. You can find details on our pricing page.
Source:: Amazon AWS