DeepSeek V4 Pro + LangChain Guide

pip install langchain langchain-openai

from langchain_openai import ChatOpenAI

llm = ChatOpenAI(
    model="deepseek-v4-pro",
    openai_api_key="napi-YOUR_KEY",
    openai_api_base="https://nex-api.tech/v1",
)

from langchain_openai import OpenAIEmbeddings
from langchain_community.vectorstores import Chroma
from langchain.chains import RetrievalQA

embeddings = OpenAIEmbeddings(openai_api_base="https://nex-api.tech/v1")
vectorstore = Chroma.from_documents(docs, embeddings)
qa = RetrievalQA.from_chain_type(llm=llm, retriever=vectorstore.as_retriever())

from langchain.agents import create_openai_functions_agent
from langchain.tools import tool

@tool
def search(query: str) -> str:
    return f"Results for: {query}"

agent = create_openai_functions_agent(llm, [search], "You are helpful")