Assuming your client-side sessions are stored in cookies, be aware of doing multiple simultaneous requests. The order in which the server processes them could b

Assuming your client-side sessions are stored in cookies, be aware of doing multiple simultaneous requests. The order in which the server processes them could be different than the order the client processes the results. This can lead to overwriting a session with an older version of the same one. Unless you are only doing one request at a time or you don't mind rolling back to older session data, avoid cookie-based client side sessions.