Dialogflow vs rasa NLU: What are the differences?
Developers describe Dialogflow as "Give users new ways to interact with your product by building engaging voice and text-based conversational apps". Give users new ways to interact with your product by building engaging voice and text-based conversational apps. On the other hand, rasa NLU is detailed as "Open source, drop-in replacement for NLP tools like wit.ai". rasa NLU (Natural Language Understanding) is a tool for intent classification and entity extraction. You can think of rasa NLU as a set of high level APIs for building your own language parser using existing NLP and ML libraries.
Dialogflow belongs to "Chatbot Platforms & Tools" category of the tech stack, while rasa NLU can be primarily classified under "NLP / Sentiment Analysis".
rasa NLU is an open source tool with 5.77K GitHub stars and 1.7K GitHub forks. Here's a link to rasa NLU's open source repository on GitHub.