# Build a data app

Build an app that answers a question with your Altertable data. Start in the Altertable app for your first build. You can also use the [Altertable Slack Agent](/docs/agents/ask.md), or use a connected agent in [Claude](/docs/agents/setup/claude.md), [ChatGPT](/docs/agents/setup/chatgpt.md), or another MCP client.

You need [connected or ingested data](/docs/lakehouse/ingest-or-connect.md) and [permission to manage data apps](/docs/administration/access-control.md). The resulting app is hosted in Altertable, where you can review and share it.

## 1. Describe the app

Open **Data apps**, start a new app, and describe the audience, question, and controls you need. Include the intended date range and metric definitions when you know them.

```text
Build a data app for our weekly signup review. Show signups over time, break them down by source, and add a date filter.
```

For a [connected MCP client](/docs/agents/setup.md), use [Analyst](/docs/agents/mcp.md#pin-a-scope) access. Send the same prompt and open the app URL returned by the agent.

## 2. Review the data

Check the catalogs, tables, joins, filters, and calculations behind the app. Compare a displayed value with a direct [SQL query](/docs/lakehouse/query/sql-explorer.md). Check how the app handles an empty result and a different date range.

## 3. Refine the app

Ask the agent for a specific change. Use annotations when you want to point to part of the app. For example, ask it to explain a metric, change a breakdown, or add a filter.

When the results and interactions match your goal, [share the app](/docs/data-apps/share.md).