It is technically possible for two different web projects to share the same Statsig API keys. However, it is generally recommended to create separate Statsig projects for distinct websites with their own userIDs and metrics. This approach aids in managing each product independently. If you aim to track success across multiple websites, you may want to manage them in the same project. The decision ultimately depends on your specific use case and goals.
As for the impact on billing, it would depend on your usage. Statsig's pricing is based on Monthly Active Users (MAUs), which are unique users that interact with Statsig in a calendar month, regardless of how many API keys are used. If the same users are interacting with both projects, it would not increase your MAUs. However, if different sets of users are interacting with each project, it could potentially increase your MAUs.
When considering whether to create/use a new Statsig project, it's important to understand when it's appropriate to do so. You can refer to the guidance provided in the Statsig documentation. If you decide to create a new project, remember that the API keys are unique per project.
In conclusion, while it's technically possible to share API keys between projects, it's generally better to have separate keys for each project for easier debugging and management. The impact on billing is based on the number of unique users interacting with Statsig, not the number of API keys used.