I don't want to use APIs from any existing sources like clarifai or google. I have a trained model, and I want predictions served via the model. How can I do it?

if I’m not mistaken, you can now save a model in Tensorflow under a Python environment and load it with Tensorflow.js; provided that you have a working knowledge of JavaScript, that seems like a good way to go about it if all you are doing is just using the trained model for prediction.

If you insist on using Python then my guess is that you have to handle it on the server side by using something like Flask or Django; I still think that it's easier to just use Tensorflow.js because the JavaScript code is trivial, unless you really don’t want to expose your model to the client at all.