If a customer has 100 unique Lambda functions but only 70 active on average, how many functions are they billed for?

In the context of billing for AWS Lambda functions, customers are billed based on the number of active functions rather than the total number of unique functions available. Since the customer has 100 unique Lambda functions but only 70 of them are actively used on average, billing will be calculated based on those actively used functions.

This model promotes cost efficiency because it ties costs directly to the resources consumed in actual operation, rather than a flat fee for all available functions. As a result, the customer would be charged for the 70 active functions, which accurately reflects their usage.