- Beam is an open-weight model from Reflection AI focused on code maintenance, tool use, and multi-step workflows.
- The model utilizes a Mixture-of-Experts (MoE) architecture with 501B total parameters and 23B active parameters.
- It is integrated into Amazon SageMaker JumpStart, supporting real-time endpoints and distributed deployment via HyperPod Inference.
AI CURATED HOT STORY · 10/16/2026
Reflection Launches 501B Open-Source MoE Model Beam for Coding and Agents
US AI startup Reflection has officially launched Beam, its first open-source large model. Utilizing a Mixture-of-Experts (MoE) architecture with 501B total parameters but only 23B active, Beam significantly reduces inference compute requirements while supporting a 1M token context window. Released under the permissive Apache 2.0 license, it is optimized for code generation and agentic tasks, offering various quantized versions to lower deployment barriers.
Cross-verified reports indicate strong performance in agentic workflow benchmarks, outperforming competitors like K2 Horizon with high token efficiency. vLLM provides native support from day one, achieving 708 tokens/s via DFlash2 speculative decoding. Kernel optimizations by coding agents further boosted batch decoding speed by 2.71x. Although weaker in terminal command-line operations, Beam approaches frontier closed-source intelligence levels.
This release impacts the open-source ecosystem significantly. AWS has integrated Beam into SageMaker JumpStart for managed deployment, signaling cloud providers' rapid adoption of high-performance open MoE models. For developers, Beam offers a balanced choice of long context, high speed, and low cost, particularly accelerating agent-based applications requiring multi-step tool calling and complex code maintenance.
HEAT TRENDHourly heat curve
2 fully observed hoursTIMELINECoverage timeline
Total 4 reports · Latest first- AWS Machine Learning BlogT1·68 pts
- Hugging Face BlogT1·85 pts
- Beam is Reflection's first open model, featuring 501B total parameters but only 23B active per token, reducing inference costs.
- The model is specialized for coding and agentic use cases, supporting a 1M token context window.
- Released under the permissive Apache 2.0 license, it includes FP8 and NVFP4 quantized versions for flexible hardware deployment.
- vLLM 官方博客T1·78 pts
- Reflection Beam is a 501B total / 23B active parameter MoE model with full native vLLM support.
- DFlash2 speculative decoding with adaptive verification achieves 708 tokens/s per request and +10% throughput at high concurrency.
- Agent-driven kernel optimization resulted in 2.71x faster batch-1 decode and 1.87x faster prefill.
- Artificial AnalysisT1·78 pts
- Beam is Reflection's first open-weights model, utilizing an MoE architecture (501B total / 23B active).
- Scores 48.5% on AutomationBench-AA, significantly outperforming rival K2 Horizon in agentic tasks.
- High token efficiency: uses half the output tokens of some competitors to achieve similar intelligence levels.
- Weakness lies in terminal command-line operations (Terminal-Bench), scoring much lower than Qwen and Muse Spark Open.