Ask HN: Help me validate my startup idea

A website to help SaaS owners to evaluate and adjust their performance over time. The SaaS owner provides monthly metrics (advertising costs&associated traffic, new trials, new subscriptions, lost subscriptions, ...) and in return key indicators are computed (cac, ltv, cogs...) and tips adapted to the situation are proposed. This would be free. A paying option would be an access to a simple api to automatically fill the metrics and generate a report each month).

Does it already exists ? Do you feel it could work ?