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Today we're launching Miles v0.1, an open-source RL framework for LLMs and multimodal models. RL training is easy to start and hard to debug. Miles helps you ensure your run is correct, use hardware efficiently, and keep RL running at scale. Over the past 9 months, 72 contributors have landed 1,326 commits, 85 GPU E2E CI tests, battle-testing Miles on frontier open models like Kimi K3, DeepSeek V4, Qwen 3.8, GLM 5.2, Inkling, MiniMax H3, etc. Miles powers frontier-model development and production RL workloads at @humansand, @periodiclabs, @modal, @DecagonAI, @Eigent_AI, @nebiusai, @IBM and more, on both @NVIDIAAI and @AIatAMD hardware. Here is what we built, and why teams picked Miles🧵
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A useful test for a primitive: can you replace one piece without touching its neighbors? The async rollout buffer is one way Miles answers that.
a lot of the features in open-source rl / inference frameworks will eventually show up in other implementations. the more interesting question is how quickly a framework gets there, and how much work it takes to actually use them. two related things seem to matter: 1 - the primitives. can you change the part you care about without pulling apart everything around it? @radixark miles’ async rollout buffer is a good example: you can change which groups of samples reach training and which prompts get retried, while reusing the rollout worker and trainer. the granularity of that interface matters. extension points should let people work on different parts of the system without constantly stepping on each other, and the contracts should be stable enough that those extensions survive upgrades. 2 - contribution velocity. getting a new attention backend running is one step. making it work with the KV cache formats, prefix caching, and speculative decoding your workload needs is more work. what matters is how quickly contributors and maintainers can get an improvement through that process and into something people can depend on. cheaper code generation makes this more interesting. it gets easier to add features and easier for everyone else to catch up. there’s still the work of integrating changes, checking correctness, and measuring performance on real workloads. good primitives help keep each contribution from turning into a project across the entire stack. if your framework makes a useful technique practical a couple weeks/months earlier, that’s invaluable time for experiments and learning. the question is whether a framework can keep giving you that head start, without making you do all the integration work yourself.
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We're proud that @periodiclabs chose SGLang and Miles to build Neon. Periodic extended SGLang and Miles to run scientific RL at trillion-parameter scale, with more efficient training, lower memory use, and 2.5x faster inference. This work was contributed back to both projects. Excited to see where teams take SGLang and Miles next.
We built high-throughput materials labs in Menlo Park to create a loop between experiments and models. The labs generate fresh data, the models learn from it, and then help us decide what to try next. Using only 1,300 H200s, plus months of our experimental data, we mid-trained and RL’d an open-source model to surpass GPT-6 Astra on our analysis benchmark. We call it Neon. This is real footage from our lab. We’re focusing first on hard problems in materials science, including superconductors, magnets, and semiconductor materials. Read our blog posts below.
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SGLang-Diffusion enables fast, scalable inference for multimodal generation. The latest work with VDN-H3 brings @MiniMax_AI H3 to faster-than-playback video generation with strong scaling across GPUs. 👏
SGLang-Diffusion with VDN-H3 now generates 14.4s of 768p video in just 9.0s 🚀 On 8× B200, 8 step denoising takes just 6.9s, reaching over 2× real time. The 9.0s figure covers the full generation request after warmup. No measured quality regression versus dense 50-step H3 across 103 test prompts. 🧵
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Miles brings Day-0 RL support to DeepSeek-V4.1-Flash. Miles keeps the trainer close to what @sgl_project samples. Parallelism and shared state let the new architecture scale intact across GPUs. Quantization-aware training mirrors SGLang's FP4/FP8 rounding, while routing replay reuses the rollout's expert choices. Numerical consistency comes from FP32 and deterministic reductions. Colocated training and rollout fit full-parameter RL on 16 GPUs. Over steps 0–80 of a DAPO run, per-token trainer–rollout KL stayed at 0.0012–0.0017 while reward rose from 0.51 to 0.78. Blog and cookbook in the comments. 📚
DeepSeek V4.1 Flash weights are out! We are shipping day-0 inference and RL support in SGLang and Miles. V4.1 extends the V4 stack with compressed KV shared across layers, a two-stage sparse indexer, and a 196B Engram lookup memory. It is natively multimodal with 552B backbone parameters, 16B active decode and 8B prefill, and supports up to 1M context. There will be some very exciting performance upgrades for this model in the next few days. Stay tuned! Supported features, blog and cookbook in the comments ⬇️
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Miles natively supports @sgl_project for fast rollouts, while keeping rollout and training aligned for reliable post-training at scale. Grateful to the community for the contributions and feedback that continue to shape Miles.
Huge congrats to the @radixark team on Miles v0.1! 🚀 Fully async agentic RL on a 744B MoE across 64 GB300s, with @sgl_project powering rollouts. Love the focus on getting rollout/training fidelity right alongside throughput. huggingface.co/papers/2609.0…
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The full technical report for Miles is now available. Miles is built for production-level post-training, with stability, efficiency, and flexibility at its core. The report covers its system design and how it works in practice.
Today we're launching Miles v0.1, an open-source RL framework for LLMs and multimodal models. RL training is easy to start and hard to debug. Miles helps you ensure your run is correct, use hardware efficiently, and keep RL running at scale. Over the past 9 months, 72 contributors have landed 1,326 commits, 85 GPU E2E CI tests, battle-testing Miles on frontier open models like Kimi K3, DeepSeek V4, Qwen 3.8, GLM 5.2, Inkling, MiniMax H3, etc. Miles powers frontier-model development and production RL workloads at @humansand, @periodiclabs, @modal, @DecagonAI, @Eigent_AI, @nebiusai, @IBM and more, on both @NVIDIAAI and @AIatAMD hardware. Here is what we built, and why teams picked Miles🧵
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Miles makes frontier post-training simple to use, easy to extend, and accessible to every team. We’re excited to see what you build with Miles.
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The real world is multimodal. For AI to understand and recreate it, models need to learn across modalities. In our latest blog, we show how Miles supports that learning with a shared post-training design for VLMs and diffusion models. Link in the comments. 🔗
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GLM-5.2 on SGLang was battle-tested and is currently serving hundreds of thousands of people in production with our partners. GLM-5.3 carries all the great things we built for it👏 We've added an experimental NVFP4 checkpoint for GLM-5.3, and Miles support for GLM-5.3 is on the way! huggingface.co/RadixArk/GLM-…
GLM-5.3 weights from @Zai_org are live, with SGLang powering day-0 serving support! GLM-5.3 inherits every optimization and feature we battle-tested for GLM-5.2 over the past months. On real-world multi-turn agentic workloads, we measured 537.6 tok/s/user on NVFP4 and 413 tok/s/user on FP8, at BS=1 with TP8 on 8x B300. It's fast, efficient, and production-ready today on @NVIDIAAI Blackwell and Hopper, and @AIatAMD MI300X/325X/355X. We believe this is a big step forward for GLM-Series in agentic tasks, with a path toward mythos-class cyber capability. Can't wait to see what people build with GLM-5.3 and SGLang🚀 Cookbook👇
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Introducing LoRA SFT in Miles-diffusion for fast, targeted post-training of diffusion models. We trained a rank-64 LoRA for @MiniMax_AI H3 to improve physical realism. Starting from 254 curated training windows, training took under 3 hours on 8 GPUs. The result is a lightweight adapter that improves targeted capabilities without retraining the full model and can be exported to safetensors and served directly with SGLang. Follow the guide in the comments to try it yourself ⚡
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Miles now supports RL training for @Alibaba_Qwen's Qwen3.8-Flash-Next and @Zai_org's GLM-5.3-Flash. Miles pairs @sgl_project SGLang rollout with Megatron training. Built on Megatron, Miles provides SGLang-consistent, high-performance training kernels. Miles implements QSA indexing + sparse attention and the ~102GB host-resident PLE table for Qwen, and KDA + DSA with kpool-compressed indexing for GLM, along with the models' hyper-connections and MoE routing. Both recipes are validated end to end on GB300 GPUs. Check the cookbooks in the comments 📖
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Congrats @Zai_org on unveiling Ox Alpha and launching GLM 5.3 Flash! We're working on an NVFP4 checkpoint for it. It'll be around 200GB and should add a promising speedup for deployment on @NVIDIAAI Blackwell🚀
GLM-5.3-Flash (320B-A18B) from @Zai_org drops today with day-0 support in SGLang. You may know it as ox-alpha from the past few days! 👀 It's the first native multimodal model in the GLM-5 series, able to review its own output visually and fix what's wrong. 🚀 It outperforms GLM-5.2 at 1/10 the cost. Hybrid sparse plus linear attention enables stable 1M long-context performance at extreme cost efficiency. 💻 It goes beyond coding into professional work: slides, documents, spreadsheets, and finance research, all handled end to end. Run GLM-5.3-Flash with SGLang, and welcome to a new era of efficient, production-ready open intelligence!
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Excited to team up with @Alibaba_Qwen, @NVIDIAAI, and @AIatAMD on Day-0 support for Qwen3.8-Flash-Next! 🚀 The RadixArk team contributed deep kernel and system optimizations to @sgl_project , alongside releasing the SGLang official Day-0 NVFP4 quantized model. Try the checkpoint and dive into the full technical post on @lmsysorg 📦 huggingface.co/RadixArk/Qwen… 📖 lmsys.org/blog/2026-08-26-qw…
Congrats to @Alibaba_Qwen on launching Qwen3.8-Flash! SGLang is proud to be a day-0 partner supporting the new architecture preview for Qwen4. It's a 125B main model with 51B of N-gram embeddings and 6B activated per token. The 51B N-gram embeddings scale model capacity with almost no extra compute per token, and can sit in host memory with async prefetch instead of occupying GPU memory. The GDN + QSA hybrid attention gives you efficient memory and precise retrieval at the same time on long-horizon tasks, while Gated Residual gives the model 4 lanes instead of 1 to pass information between layers. And it's trained with Muon! We're excited for what's next with Qwen4, and we already have plenty of ideas for how to use the N-gram embeddings in new deployment setups. Stay tuned! Blog and cookbook in the comments👇
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Shipping alongside Miles v0.1, Mooncake lands as a new rollout data-transfer backend in Miles, making remote GET 10-14× faster than the existing path. With @KVCache_AI, we gave the rollout-to-training handoff a dedicated data plane: - 1.2-1.6× faster PUT via structured-object transfer - Structure-aware PUT/GET optimizes serialization and bulk RDMA transfer, including zero-copy reconstruction from registered buffers on GET - Same put/get calls, no change to the RL programming model Read the full blog 👇 link in the comment
Excited to team up with @radixark to make large-scale RL data movement faster 🚀 Miles is built for high-performance, large-scale post-training, and Mooncake is now integrated as a rollout data-transfer backend for the fragmented, heterogeneous data moving between rollout and training in disaggregated RL. On rollout data captured from Miles: ⚡ 10–14× faster remote GET ⚡ 1.2–1.6× faster PUT By turning fragmented rollout objects into efficient bulk I/O while preserving their original structure, Mooncake helps reduce rollout-to-training handoff latency without changing the RL programming model. Read more: kvcache.ai/blog/mooncake-rl-…
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