draw.io online is a free-to-license web application for everyone. It is free for any usage, there is no premium pay-for functionality, watermarking, etc. You own the content you produce and may use it for any purpose. We don't sell your personal information or data.
There are some exceptions where we do charge for specific integrations, we publish a summary of pricing at the start of each year.
Our business model is, in addition to charging for certain integrations, we sell the underlying technology to companies to create custom diagramming applications. draw.io advertises and demonstrates this technology.