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

# BigQuery

The BigQuery source lets you extract tables or custom SQL queries from Google BigQuery into Less.

### Authentication

Less connects to BigQuery with a **Google Cloud service account JSON key**. This is the recommended approach for automated extract jobs.

**OAuth (sign in with Google) is not supported yet** for BigQuery. Other Google connectors in Less (such as Google Sheets) use OAuth, but the BigQuery source and destination currently require a service account.

See [How to create a BigQuery service account](/sources/guides/bigquery-service-account) for step-by-step instructions.

### Setup

<Steps>
  <Step title="Account">
    Enter your Google Cloud **project ID**. Optionally set a default **dataset** to limit table discovery, and a **location** if your queries run in a specific region (for example `US`, `EU`, or `europe-west1`).
  </Step>

  <Step title="Credentials">
    Upload your **service account JSON key file**. The service account needs **BigQuery Data Viewer** on the datasets you want to read and **BigQuery Job User** at project level so Less can run queries.

    See [How to create a BigQuery service account](/sources/guides/bigquery-service-account) if you need help creating the key.
  </Step>

  <Step title="Tables">
    Click **Connect** to verify the credentials and load available tables. Then either select tables from the list or switch to query-based mode and provide one or more custom SQL queries.

    <Warning>
      You can select either Table or Query-based. You cannot select both.
    </Warning>
  </Step>
</Steps>