Multi-Model Routing Strategy Builder

What Is Multi-Model Routing?

Multi-model routing is a cost optimization strategy where you route different types of requests to different AI models based on their complexity. Instead of sending every request to an expensive premium model, you classify requests and use the cheapest model that can handle each task well.

The 3-Tier Routing Strategy

• Tier 1 — Simple (60-70% of traffic): Classification, extraction, formatting, simple Q&A. Use GPT-4o mini, Gemini Flash, or DeepSeek V4 Flash ($0.075-$0.15/M input).
• Tier 2 — Medium (20-30% of traffic): Summarization, translation, moderate reasoning. Use Claude Haiku, GPT-4o, or Mistral Large ($1-$2.50/M input).
• Tier 3 — Complex (5-15% of traffic): Code generation, deep analysis, multi-step reasoning. Use GPT-5, Claude Opus, or Gemini Pro ($1.25-$5/M input).

How to Classify Requests

The key to model routing is accurate request classification. Common approaches:

• Rule-based: Route by endpoint, user tier, or request length. Simple and fast.
• Classifier model: Use a cheap model (GPT-4o mini) to classify complexity before routing. Adds ~$0.0001 per request.
• Hybrid: Rules for obvious cases, classifier for ambiguous ones. Best balance of speed and accuracy.

Real-World Savings Example

A SaaS app processing 50,000 requests/month with an average of 1,200 input / 400 output tokens:

• Without routing (all GPT-5): $1,125/month
• With 3-tier routing: $189/month — 83% savings
• Annual savings: $11,232

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