Auto Router [Add-on]
Auto Router chooses which model handles each request to your LiteLLM gateway. Your application calls one model name; the router selects from the models you configure based on the prompt or your routing rules. For example, you can send simple questions to a cheaper model and harder tasks to a stronger one.
Building routing into a Python application or agent? Use the Autorouter SDK.
You choose the models for each tier. For each request, the router picks a tier and a model from it.
Set up in the dashboard
You need a LiteLLM gateway with models already configured and permission to add models. If you do not have a gateway yet, start with the gateway quickstart.
- Open Models + Endpoints, then the Auto Router tab, and add a router.
- Give it a name, such as
smart-router. Click Configure automatically to fill the tiers from your deployed models, then review the selections. - Use Test Routing with a prompt from your application. Check which tier and model it selects. This tests the routing decision without calling the selected model; an LLM classifier can still incur a charge.
- Click Add Auto Router to save it. In your application's requests to the gateway, use
smart-routeras themodel.
The selected model generates the answer. Try a few of your application's tasks and compare the answers and cost with your current model before switching traffic.
For YAML, the API, or CLI setup, see Admin Setup. To use the router from Claude Code or Codex, follow User Setup.
To change how the router chooses models, see Customize your classifier. You can also connect a decision model, including Jev, Nimble, Laya, or Databricks ai_decide.
Results
| Result | Measured on | Read more |
|---|---|---|
| JEV: 5.43x as fast as Haiku by median classification latency and 96.12% lower registry-priced classifier cost | 80 authored synthetic cases, three paired repeats, 95.00% vs 73.75% match with authored expected tiers under one fixed rubric | JEV comparison |
| Claude Opus-5 solve rate at 27% lower cost | 21-task subset of Terminal-Bench 2.0, 16/21 solved by both | Terminal-Bench |
| Heuristic v2: 27% more tasks solved at 45% lower cost per task than v1 | Same 21-task subset, no LLM classifier call | Heuristic v2 |
| 74.5% cheaper at 87.3% of frontier quality | RouterArena, 8,399 graded queries | Cost and quality |
| 51.1% saved, $12,249 over four months | 272,876 production requests, 450+ users | Production case study |
| 37% to 69% cheaper than caching alone | Five datasets including live gateway traffic | Prompt caching |
| Matched or beat the current model on 88.1% of responses | Shadow evaluation on live traffic, 143 judged turns | Shadow evaluations |
Configure and evaluate
Release posts
- Harness-Aware Routing: Claude Code and Codex context handling, encrypted delegated tasks, and classifier logs
- Mid-Task Stall Escalation: bumps a request one tier when it's stuck in a retry loop
- Auto Router v2: one router for complexity, semantic, and adaptive routing
- 1-click presets and Test Routing
- Savings tab and per-request classifier cost
- Classifier context and usage benchmarks
- Shadow evaluations
- Context-size and modality routing