I Built My Own ChatGPT in Under 2,000 Lines of Code. The Hard Part Wasn’t the AI.
Everyone who’s used ChatGPT has wondered: could I build my own? The answer is yes — in under 2,000 lines of code and an afternoon’s work. But the real challenge isn’t the AI. It’s the thousand small UX details — streaming, thinking-process separation, error handling — that separate a toy from a product. Here’s the blueprint.