> ## Documentation Index
> Fetch the complete documentation index at: https://docs.gu1.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Check value in lists by type

> Check whether a value appears in any active data list of a given type for the tenant, used for runtime screening — POST /data-lists/{type}/check.

## Overview

Runs the **isInDataList** lookup for the given **list type** (e.g. `custom`, `company_blocklist`). Useful for runtime screening without referencing a specific list UUID.

## Endpoint

```
POST https://api.gu1.ai/data-lists/{type}/check
```

## Authentication

```bash theme={null}
Authorization: Bearer YOUR_API_KEY
Content-Type: application/json
```

## Request Body

<ParamField body="searchValue" type="any" required>
  Value to match (string, number, or structured object depending on type).
</ParamField>

<ParamField body="options" type="object">
  * `includeMetadata` (boolean): include match metadata in the response.
  * `useCache` (boolean): defaults to **true**; set `false` to bypass cache.
</ParamField>

## Response

`found`, `listType`, `searchValue` (redacted when non-string), `matches`, `matchCount`, plus `performance` timing and optional `cacheHit`.