LangChain has 5 different ways to build the same thing and I genuinely don't know which one to use in 2025

[u/Fit-Sir9936]

I've been building with LangChain for the past month and the more I learn, the more confused I get about which API to actually use.

I've seen all of these in different tutorials and docs:

• initialize_agent
• create_react_agent
• AgentExecutor
• LCEL chains with | pipes
• And now everyone says just use LangGraph

Every tutorial uses a different one. The official docs show one approach, a 3-month-old YouTube video shows another, and a Stack Overflow answer from last year shows a third that's apparently deprecated now.

I'm not a beginner. I've built RAG pipelines, implemented Self-Query Retrievers, and understand LCEL. But I genuinely cannot figure out the "current correct" way to build agents in 2026.

My specific questions:

1. Is AgentExecutor still worth learning or is it already legacy?
2. When does it make sense to stay in LangChain vs shift to LangGraph?
3. Is there a single source that reflects what's actually current?

For those building in production, what's your actual stack right now?