Reflection AI Launches Beam: 501B Open-Weight MoE Model With 23B Active Parameters

Reflection AI has released Beam, a 501-billion-parameter open-weight Mixture-of-Experts model that activates only 23 billion parameters per forward pass, targeting coding and agentic workloads. The open-weight release makes Beam accessible for self-hosted deployment, giving developers a powerful alternative to closed frontier models for code generation and autonomous task execution. With its MoE architecture, Beam delivers high-capacity reasoning while keeping inference costs manageable relative to its total parameter count. This positions Beam as a direct competitor to other large open-weight coding models and is particularly relevant for teams building agentic pipelines that require strong code understanding. Developers can evaluate Beam for use cases where model control, customization, and on-premise deployment are priorities.