---
title: Browser Integrity
description: Detect and block requests with invalid headers.
image: https://developers.cloudflare.com/cf-twitter-card.png
---

> Documentation Index  
> Fetch the complete documentation index at: https://developers.cloudflare.com/learning-paths/llms.txt  
> Use this file to discover all available pages before exploring further.

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# Browser Integrity

Cloudflare's Browser Integrity Check (BIC) looks for common HTTP headers abused most commonly by spammers and denies access to your page.

It also challenges visitors without a user agent or with a non-standard user agent such as commonly used by abusive bots, crawlers, or visitors.

[BIC is enabled by default](https://developers.cloudflare.com/waf/tools/browser-integrity-check/).

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```