> ## Documentation Index
> Fetch the complete documentation index at: https://docs.weflayr.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Fallback and model health

> When a model is down, or failing, the gateway sends the call to the next one.

A call through the gateway rarely depends on one provider. The same model is often served by several providers and regions, and a routing strategy lists several models.

## How it works

When a call fails, the gateway sends it to the next option instead of returning the error. A model that is down or unhealthy is tried after the other options, so most calls never reach it.

## What is tried next

* **A routing strategy** tries its models in the order of its rule: the router's ranking under dynamic routing, your order under fixed order. Each model is tried on its deployments, then the next model.
* **A call naming a model** tries every provider and region serving it, or the ones you list in `provider` and `region`. `model` can also be a list of models, tried in order.

A timeout, a network failure or a provider server error can retry the same model first (**Retry on error** in a routing strategy, `retry_on_error` on a call). Any other failure moves the call on.


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