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

# Test Run Configuration

> Configure regions, shards, and notifications for your test runs

## Region

Select where your tests execute.

| Region                | Code         | Best for      |
| --------------------- | ------------ | ------------- |
| US East (N. Virginia) | `us-east-1`  | North America |
| Asia (Mumbai)         | `ap-south-1` | Asia & Europe |

## Shards

Sharding splits your test suite across multiple parallel workers, reducing total execution time.

Configure 1–50 shards per run. You can set a per-project default and override it for individual runs. Tests are automatically distributed across shards for balanced execution.

After each run, the **Shard Analysis** view shows distribution and performance metrics — useful for spotting imbalanced shards and optimizing split.

## Notifications

Get notified when a test run completes or fails.

* **Email** — sent to configured recipients
* **Slack** — delivered to subscribed channels

Configure notification preferences from **Settings > Notifications**.