One million real conversations between users and 25 different state-of-the-art LLMs collected from Chatbot Arena. Invaluable for understanding real-world usage patterns, language diversity, and human preferences — spans 154 languages and covers everyday tasks, creative writing, coding, and more.
Dataset Details
Provider
lmsys
Category
Instruction / SFT
Size
1M Conversations
License
CC BY-NC 4.0
Downloads
740k
Tags
Real-world, Multi-model, Diverse, 154 Languages, Human Conversations
from datasets import load_dataset
ds = load_dataset("lmsys/lmsys-chat-1m")
Fine-tune with this dataset
Estimated VRAM to fine-tune with QLoRA (4-bit base model + LoRA adapters), using conservative defaults:
Python-Edu — Continued pretraining for Python code understanding
OpenHermes 2.5 — The default general-purpose SFT mix for 7B-13B fine-tunes
Frequently asked questions
Can I use LMSYS-Chat-1M commercially?
Not in a product — LMSYS-Chat-1M is released under CC BY-NC 4.0, which restricts use to research and other non-commercial purposes. For commercial fine-tuning, pick a permissively licensed dataset from the same category instead.
How much data does LMSYS-Chat-1M contain, and do I need all of it?
LMSYS-Chat-1M contains 1M Conversations. You rarely need all of it: for style and format fine-tuning, a few hundred to a few thousand examples are enough — load a slice (e.g. split="train[:1000]") and scale up only if quality plateaus.
What is LMSYS-Chat-1M best used for?
Studying real-world usage patterns across 25 models (non-commercial). It belongs to the Instruction / SFT section of our dataset hub, where you'll find alternatives and complementary sets.