SuperTokens is an open source authentication solution offering features like: Different types of login: Email / password, Passwordless (OTP or Magic link based).

SuperTokens.com

so as I see 5000 MAU is free for hosted plan , please can you confirm if i increase the user base to 10000 , then will be charged only for 5000 users i.e. 10000-5000

No, that's not correct. If you increase the user base to 10,000, you will be charged for all 10,000 users, not just the additional 5,000 users. The pricing is based on the total number of monthly active users (MAUs) you have, not just the increase in MAUs.