I built the same AI app with and without LangChain. Here's what I learned.

I'd used ChatGPT and Claude as a regular user for a while, but I had no idea what it actually takes to build something like that yourself — what tools developers reach for to make an AI app. LangChain kept coming up as "the" framework for this, so I decided to find out what it actually does.

So I built the same small AI app twice — first with raw API calls, then with LangChain — and wrote down everything I noticed along the way. This is the honest report.

If you've been intimidated by LangChain or wondering whether to learn it as a beginner, this is for you.

What I built

The app is a "document Q&A" — load a text file, ask the AI questions about its contents, and have a conversation with memory (so the AI remembers what you asked before).