Understanding Webhook Size Limits and 413 Error Solutions

What’s the size limit for the webhook? I’m trying to build a workaround so that we (Adyntel) don’t send a response that’s higher than the cell size but if I send a JSON that’s estimated to be bigger than 100kb I always get a 413 error from you guys. The cellsize limit is 200kb so I’m not sure why this happens with 100kb (just had this happen with 119kb)