I'm currently evaluating memory overhead for a variety of simple Websocket based echo server to get a gauge of minimal memory penalty per connection along with SSL overhead per connection. I've created two websocket servers in Haskell: https://github.com/bbangert/ssl-ram-testing/tree/master/Haskell One using Yesod + jaspers Websockets lib, the other with Yesod + Mishael Snoyman's native websocket lib. I was curious what options I might be missing that would ensure a more efficient use of memory, at the moment the non-SSL seems to use about 48kb per connection, while using Haskell's TLS via warp-tls introduces a huge amount of overhead (along with odd handshake issues). Here's what my results look like: No SSL Program started. Tester started. Tester finished connecting. Waiting: 360 Last Memory Increase: 2 WARNING: Program hasn't stopped increasing. Started with: 2633728 Ended with: 50896896 kB per connection: 47.13 SSL Program started. Tester started. yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record mac",True,BadRecordMac)) yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record mac",True,BadRecordMac)) yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record mac",True,BadRecordMac)) yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record mac",True,BadRecordMac)) yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record mac",True,BadRecordMac)) yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record mac",True,BadRecordMac)) yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record mac",True,BadRecordMac)) yesod-customws-tls: HandshakeFailed (Error_Protocol ("bad record mac",True,BadRecordMac)) WARNING: Failed to connect all clients Tester finished connecting. Waiting: 360 Last Memory Increase: 4 WARNING: Program hasn't stopped increasing. Started with: 3170304 Ended with: 454221824 kB per connection: 444.03 SSL Overhead per Conn: 396.90 I wait up to 6 minutes for memory to level out, it never does with or without SSL. Is this expected behavior? If not, what options am I missing? The ssl-ram-testing repo includes full directions on how to reproduce this and run this test. Cheers, Ben