verl alternatives
Curated alternatives to verl — and why you'd switch.
slime
THUDM's RL post-training framework behind the GLM releases — Megatron training plus SGLang rollouts with native arg pass-through, and pluggable reward, verifier and agentic data-generation workflows.
Why switchSame job — large-scale RL post-training. verl bets on multi-backend flexibility (FSDP/Megatron × vLLM/SGLang) where slime hard-commits to Megatron+SGLang; pick verl when your infra is vLLM- or FSDP-shaped.
Full comparison →trl
Hugging Face's post-training library: SFT, DPO, GRPO, KTO and reward-model trainers on top of Transformers — from a Colab LoRA run to multi-GPU deployments.
Why switchSame goal — a post-trained model — at opposite ends of the infra spectrum: TRL for Hub-native single-node SFT/DPO/GRPO, verl when the job needs disaggregated rollout engines and multi-node RL dataflows.
Full comparison →