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

# Use block user

> Block another user

## Overview

Returns a function that blocks a user by their ID. On a new block, the server retroactively removes any existing follows and connections between the two users (both directions). Blocking is idempotent — re-blocking an already-blocked user succeeds.

<Note>
  Requires the `moderation` bundle. See [Moderation — Blocking](/sdk/moderation/overview#blocking).
</Note>

## Usage Example

```tsx theme={null}
import { useBlockUser } from "@sublay/react-js";

function BlockAction({ userId }: { userId: string }) {
  const blockUser = useBlockUser();

  return <button onClick={() => blockUser({ userId })}>Block</button>;
}
```

## Parameters

The hook returns a function. That function accepts:

<ParamField path="userId" type="string" required>
  The ID of the user to block (the target).
</ParamField>

## Returns

The returned function resolves to `void` on success.

## Related

* [useUnblockUser](/hooks/blocks/use-unblock-user)
* [useBlockManager](/hooks/blocks/use-block-manager) — combines block/unblock with status loading