How to initialise a model in langchain?

Q: How to initialise a model in langchain?

npm install @langchain/openai import { initChatModel } from "langchain"; process.env.OPENAI_API_KEY = "your-api-key"; const model = await initChatModel("gpt-5.4"); const response = await model.invoke("Why do parrots talk?"); import { ChatOpenAI } from "@langchain/openai"; const model = new ChatOpenAI({ model: "gpt-5.4", apiKey: "your-api-key" });

Difficulty: 5/10

model initialization, LLM configuration, environment management

LangChain supports all major model providers through dedicated integration packages. Each provider package implements the same standard interface, so you can swap providers without rewriting application logic. New model names work immediately — no LangChain update required — because provider packages pass model names directly to the provider’s API.

Basic implementation using initChatModel:

Implementation using Model class

Scenario Questions

0-2 years experience

Follow-up Questions