FFN replaced by 8 expert modules - only top-2 activated per token
token
→
router (softmax)
→ top-2
E0
E1
E2
E3
E4
E5
E6
E7
Active experts highlighted. Weight = router's confidence for this token.
Click "Route Token" to see logits
Expert load histogram will appear after routing tokens
Routing entropy
0.00 bits
Load imbalance
0%
FLOPs activated
25%
FLOPs saved
75%
Controls
n_experts8
412
top_k2
14
Capacity4
MoE replaces FFN with N experts. Only top-k fire per token. Total params scale with N, but FLOPs only scale with k.
Used in: Mixtral 8×7B, GPT-4 (rumored), Switch Transformer.
Mixture of Experts (MoE) Architecture - Interactive Visualization
In a Mixture of Experts model, each token is routed to only top-k of N expert FFN layers, making the model sparse - most parameters inactive for any given token. Mixtral 8×7B uses 2 of 8 experts per token, giving GPT-3.5-class quality with ~3× fewer active FLOPs. This demo shows how the router dispatches tokens and tracks expert load.
Router heatmap - see which experts each token selects and the softmax scores assigned by the gating network
Expert load tracker - watch how uniform vs skewed routing affects which experts become overloaded
Active FLOPs calculator - compare total parameters vs active parameters per token at different k and N values
Load balancing loss - see why auxiliary load balancing loss is necessary to prevent all tokens routing to one expert
Understand why MoE scales total capacity cheaply but complicates distributed inference across GPUs
Part of the EngineersOfAI Interactive 3D - free interactive visualizations covering every major concept in machine learning and AI engineering. Hover any element for a plain-English explanation. No code required.