Give me an English sentiment analysis engine

I want to buy an English sentiment analysis engine which we will get right to use and potentially re-distribute it (list all the licenses if you use open source code). You will also need to provide the training database you use for training this engine. The final deliverable is as below: 1. A webAPI which can digest an article/sentence and output sentiment score and confidence. This function has to come with test functions to make sure the quality. 2. Source code with open source license list 3. Database you use for training [login to view URL] Document