Extend an existing Flowise App

I'm in need of a seasoned developer who can widen the data sources of an ongoing Flowise application to harness OpenAI and Langchain. The project's scope requires:

- Retrieval of data from an existent Pinecone index
- Performing external API calls with "post" for varying endpoints

Currently, the flowise app gets data from existing pinecone index. You are required to extend flowise sources using API calls.