Definition
Plain language
A widely used open-source RLHF training framework.
As stated in the literature
An open-source LLM RLHF toolkit built on top of DeepSpeed, frequently used in academic and lab post-training pipelines.
Why it matters: It lowers the engineering barrier to large-scale RLHF, letting more groups actually train policies rather than just write about them.
For example, a lab uses OpenRLHF to run PPO fine-tuning of a 70B model across many GPUs with DeepSpeed handling memory.
Heard on the show
“… And because DeepSpeed is the engine under three of the most popular SFT libraries — OpenRLHF, Llama-Factory, and TRL — every academic group running SFT through any of those libraries with CPU …”Episode 009 — How Two Silent Library Bugs Quietly Invalidated a Wave of Reasoning Papers