Maybe I'm not understanding. But in a JWT you can verify the signature from when you originally signed that user's JWT. So even if I change some data in my JWT,

Maybe I'm not understanding. But in a JWT you can verify the signature from when you originally signed that user's JWT. So even if I change some data in my JWT, on the backend it will not match the signature. So just reject if it doesn't match, say someone change permission:read to permission:admin https://jwt.io/ https://jwt.io/