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AxisRL
AxisRL is an agentic RL post-training framework built on SGLang rollout, Megatron training, and real-world agent workflows.
AxisRL connects high-throughput rollout, large-scale training, weight synchronization, data movement, resource scheduling, and reproducible debugging inside one coherent framework. SGLang and Megatron remain the core serving and training engines; AxisRL handles the system layer around agentic post-training.
✨ Highlights
- Built on SGLang for high-throughput rollout and Megatron for large-scale distributed training.
- Used in agent RL workflows with 300+ turn trajectories and training runs at hundreds-of-billions-parameter scale.
- Provides configurable policy optimization objectives including PPO, GRPO/GRPO2, GSPO, TOPR, TIS, and related variants.
- Supports both white-box agent environments and black-box harness capture through an OpenAI-compatible proxy.
- Reduces rollout/training idle time with partial rollout and a lightweight control plane.
- Provides handle-based data movement, context packing, routing replay, mismatch analysis, and spike replay for rollout-trainer consistency.
🧭 Why AxisRL?
LLM post-training workloads are moving beyond single-turn question answering. In agentic RL, a model may interact with a long-lived environment, call tools, observe tool results, update context, and receive a reward only after several turns.
That changes the job of a post-training framework. It has to coordinate multi-turn rollout, environment state, tool calls, verifiers, reward collection, training sample construction, and weight synchronization. It also has to make training behavior observable, because small differences in tokenization, chat templates, logprobs, routing, packing, or weight sync can appear later as loss spikes, reward instability, or rollout-trainer mismatch.
AxisRL is designed for this setting: real agent workflows, SGLang rollout, Megatron training, and the system contracts between them.
🏗️ Architecture
At a high level, an AxisRL run follows this loop:
- Rollout actors execute task-specific agent workflows.
- SGLang workers serve model generation.
- Environments, tools, verifiers, or external harnesses produce interaction records and rewards.
- Megatron workers consume training sam