Looking for quick advice on an Echeck / ACH processing.

Sorry, I am not sure where else to ask. I am going to be doing mostly payment processing, so I will need to be doing direct payments into people's accounts. I have procrastinated in this part of the process, but I would really like to be able to send payments by Dec 1. Only a couple dozen a month at first, we'll see how it grows. Looking for something with flexible integration, this project is in python if that matters. We will also be accepting infrequent medium sized deposits.