# A RÚIAN API for Czech buildings and addresses

> The baseray API returns the whole building record for an area or one building over REST, with no exports to download and join.

## One request. The largest buildings in part of Prague, by volume.

```sh
curl "https://api.baseray.ai/v1/buildings?bbox=14.40,50.07,14.45,50.09&sort=volume&limit=10" \
  -H "Authorization: Bearer $BASERAY_API_KEY"
```

Create an API key in the app under Settings → API keys. Each key may make 60 requests a minute; a workspace 5,000 a day.

- [API reference](https://baseray.ai/docs/api)
- [MCP server for ChatGPT and Claude](https://baseray.ai/docs/mcp)
- [OpenAPI document](https://baseray.ai/docs/api/openapi.json)

## What the API returns. A building record, not just an address point.

- **Buildings in an area.** Address, category, floors, dwellings and entrances, footprint, height and volume. Unknown values are null, never guessed.
- **Measured or estimated.** Every height and volume says how it was obtained.
- **Roof and panels.** Solar potential where the roof has been modelled, and a panel check with the date of the photo.
- **Businesses at the address.** Entities registered at the building’s official address, with their IČO. Never shown as owners.

## From a key to your first buildings. Three steps.

1. **Create a key.** In the app, under Settings → API keys.
2. **Send a request.** GET /v1/buildings with an area, a sort and a limit, the key in the Authorization header. Everything is in the [API reference](https://baseray.ai/docs/api).
3. **Or ask in a chat.** Through the [MCP server](https://baseray.ai/docs/mcp), ask about buildings in ChatGPT or Claude.

## API questions. What the record holds, and what it does not yet.

### Is RÚIAN free?

Yes. ČÚZK provides RÚIAN data free through its [public remote access portal](https://vdp.cuzk.gov.cz/), as files and as WMS and WFS services.

### Does the baseray API return RÚIAN codes?

Not yet, and no completion dates either. If you need them, use the [ČÚZK services](https://www.cuzk.gov.cz/ruian/Poskytovani-udaju-ISUI-RUIAN-VDP.aspx).

### Can I use it from ChatGPT or Claude?

Yes, through the baseray MCP server. The [MCP docs](https://baseray.ai/docs/mcp) have setup steps per client.

---

- [API reference](https://baseray.ai/docs/api)
- [Open the live map](https://app.baseray.ai)
- Links and facts checked on 8 Oct 2026
- https://baseray.ai/ruian-api