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

# Regions

> Learn what serves Corti Models in each region, and how to reach it.

Corti Models is served differently depending on your project's region.

|                 | EU project                                                                                     | US project                            |
| --------------- | ---------------------------------------------------------------------------------------------- | ------------------------------------- |
| Served by       | Corti-operated European cluster, `corti-s1` model family                                       | Azure-hosted OpenAI models            |
| Data processing | Stays in the EU, never touches US cloud providers, never used for training                     | Routed through Azure                  |
| Base URL        | `https://ai.eu.corti.app/v1`                                                                   | `https://ai.us.corti.app/v1`          |
| Model IDs       | `corti-s1`, `corti-s1-instant`, `corti-s1-mini`, `corti-s1-mini-instant`, `corti-s1-embedding` | Same IDs, different underlying models |
| How to get it   | An EU project and EU API keys                                                                  | A US project and US API keys          |

<Warning>
  The same model ID does not return the same model in both regions. If you run evaluations or pin a model version, treat EU and US as separate targets: a result from a US project doesn't tell you anything about the EU-hosted model behind the same ID, or vice versa.
</Warning>

## Choosing a region

Your project's region is set when you create it in the Corti Console, and every API client created under that project inherits it. See [Environments & Tenants](/authentication/environments_tenants) for how regions work across the rest of the Corti API.

## Next steps

<CardGroup cols={2}>
  <Card title="Models" icon="microchip" href="/models/models">
    Compare the four model variants by capability, reasoning, speed, and price.
  </Card>

  <Card title="Quickstart" icon="rocket" href="/models/quickstart">
    Make your first Corti Models API call with any OpenAI SDK.
  </Card>

  <Card title="Code with Corti" icon="terminal" href="/models/ai-coding-agent">
    Connect your terminal coding agent to Corti Models in a few minutes.
  </Card>

  <Card title="Environments & Tenants" icon="key" href="/authentication/environments_tenants">
    How regions, tenants, and authentication work across the Corti API.
  </Card>
</CardGroup>