This document discusses various natural language processing APIs and techniques: 1. It discusses end-to-end APIs that can perform tasks like question answering without requiring specifying rules or patterns. Examples of applications that can use these APIs are chatbots and FAQ systems. 2. It also discusses using domain-specific languages like SQL within APIs to query databases and knowledge bases. Sequence-to-sequence models are mentioned for translating natural language to structured queries. 3. Various natural language processing tools and techniques are mentioned that can be used as part of APIs, such as word embeddings, parsers, named entity recognition, and semantic role labeling.