# Regions and base URLs

> Kustomer's US, EU and India regions, the org-specific API host, and the other hostnames an integration talks to.

Source: https://developer.kustomer.com/docs/get-started/regions-and-base-urls

Kustomer runs in three regions: the United States, the European Union and India. Every org lives in exactly one, and its data stays there. API keys and OAuth tokens only work in the region where they were issued.

## Use your org host

The simplest rule: **always call your org's own API host.**

```text
https://<your-org>.api.kustomerapp.com
```

It routes to the right region automatically, so the same code works for US, EU and India orgs. Your org name is the subdomain you sign in at: `acme.kustomerapp.com` means `acme`.

## Regional hosts

The API reference also lists the regional hosts. They're useful when you don't know the org name, for example in multi-tenant tools that only store a token.

| Region         | API host                            |
| -------------- | ----------------------------------- |
| United States  | `https://api.kustomerapp.com`       |
| European Union | `https://api.prod2.kustomerapp.com` |
| India          | `https://api.prod4.kustomerapp.com` |

> **Region mismatch:** Sending a token to the wrong region fails with an error like `Auth token associated with pod prod2 but request is being handled by prod1`. The fix is to use the org host, or the regional host that matches the org.

The **Try it** panel in the [API reference](https://developer.kustomer.com/api) has a region selector with the same options: your org host, US, EU and India.

## Other hostnames

| Host                                | Used for                                                           |
| ----------------------------------- | ------------------------------------------------------------------ |
| `https://<org>.kustomerapp.com`     | The Kustomer web app, and the OAuth `/oauth/authorize` endpoint    |
| `https://<org>.api.kustomerapp.com` | REST API and the OAuth `/oauth/token` endpoint                     |
| `https://cdn.kustomerapp.com`       | Static assets, including the web chat SDK at `/chat-web/widget.js` |

If your network filters outbound traffic, allow HTTPS to `*.kustomerapp.com`.

## Multi-region integrations

If you build for many Kustomer orgs, for example a marketplace app:

- Store the org name with each customer's credentials, and build the base URL from it.
- Never send one org's token to another org's host.
- Treat region as a property of the org, not of your deployment. A single deployment can serve US, EU and India orgs.