导航|地址|刷新
Bot detection engines

Skip to contentDocumentation Index
Fetch the complete documentation index at: https://developers.cloudflare.com/bots/llms.txt
Use this file to discover all available pages before exploring further.

Docs Directory API SDKs Changelog

Search

Log in

Bots

/

Overview

Plans

Get started

Bot Fight Mode

Super Bot Fight Mode

Bot Management

Concepts

Bots

Overview

Verified bots

Bot scores

Bot tags

Bot Feedback Loop

Bot detection engines

Additional configurations

JA3/JA4 fingerprint

Overview

Signals Intelligence

Detection IDs

Overview

Account takeover detections

Scraping detections

Additional detections

JavaScript detections ↗

Sequence rules

AI LabyrinthBeta

Block AI Bots

Custom rules

robots.txt setting

Static resource protection

Bot Analytics

BotBase

Attribution Business Insights

Workers templates

Delay action

Account Abuse ProtectionEarly Access

Troubleshooting

Bot Management skips

Super Bot Fight Mode for WordPress

False positives

Reference

Bot verification methods

Web Bot Auth

IP validation

Bot Management variables

Machine Learning models

Bot Detection Alerts

Sample terms

Glossary

Changelog

Agent resources

Agent setup ↗

Cloudflare Skills ↗

Code Mode MCP Server ↗

Domain-specific MCP Servers ↗MCP

Bots llms.txt ↗

Bots llms-full.txt ↗

Cloudflare Docs llms.txt ↗

Cloudflare Docs llms-full.txt ↗

Home

/Bots

/Concepts

/Bot detection engines

Bot detection engines

Last updated May 5, 2026|Copy as Markdown|View as Markdown|Agent setup

OverviewHeuristicsJavaScript detectionsMachine Learning (Business and Enterprise)Anomaly detection (Enterprise)Notes on detection

Cloudflare uses multiple detection engines because different bot types require different detection strategies. Simple bots can be caught by pattern matching against known signatures, while sophisticated bots require machine learning and behavioral analysis.

The engines available to your domain depend on your plan.

Heuristics

The Heuristics engine processes all requests. Cloudflare conducts a number of heuristic checks to identify automated traffic, and requests are matched against a growing database of malicious fingerprints.

JavaScript detections

The JavaScript Detections (JSD) engine identifies headless browsers and other malicious fingerprints. This engine performs a lightweight, invisible JavaScript injection on the client side of any request while honoring our strict privacy standards ↗. We do not collect any personally identifiable information during the process. The JSD engine either blocks, challenges, or passes requests to other engines.

JSD is completely optional. To adjust your settings, configure Super Bot Fight Mode from Security > Bots.

Machine Learning (Business and Enterprise)

The Machine Learning (ML) engine accounts for the majority of all detections, distinguishing between human and bot traffic. This approach leverages our global network, which proxies billions of requests daily, to identify both automated and human traffic.

The ML system uses a supervised machine learning methodology to determine the final Bot Score (1–99).

The core model relies on the following process:

Input Variables (X): Various request features (headers, session characteristics, and browser signals) collected from traffic across the Cloudflare network.

Output Variable (Y): The predicted probability that a client is human (such as the probability of successfully solving a Challenge). This probability is mapped to the final 1–99 Bot Score.

We constantly train the ML engine on a periodic basis using vast, anonymized data to ensure it remains accurate and adapts to new threats. Customers can analyze the request features used by these models via their own logs, such as Cloudflare Logpull or Logpush.

The ML engine identifies likely automated traffic.

Anomaly detection (Enterprise)

Deprecation notice

Cloudflare is deprecating the Anomaly Detection engine and is not onboarding new customers. Future behavioral detections will cover the same detection areas.

The Anomaly Detection (AD) engine is an optional detection engine that uses a form of unsupervised learning. Cloudflare records a baseline of your domain's traffic and uses the baseline to intelligently detect outlier requests. This approach is user agent-agnostic and can be turned on or off by your account team.

Cloudflare does not recommend AD for domains that use Cloudflare for SaaS or expect large amounts of API traffic. The AD engine immediately gives automated requests a score of one.

Notes on detection

Cloudflare uses the __cf_bm cookie to smooth out the A score from 1 to 99 that indicates how likely that request came from a bot, in which 1 to 29 is likely automated and 30 to 99 is likely human.
" class="glossary-tooltip" tabindex="0" data-astro-cid-hklyqugd>bot score and reduce false positives for actual user sessions.

The Bot Management cookie measures a single user's request pattern and applies it to the machine learning data to generate a reliable bot score for all of that user's requests.

For more details, refer to Cloudflare Cookies.

You can disable the __cf_bm cookie using the bm_cookie_enabled field via the API.

PreviousBot Feedback Loop NextOverview

Was this helpful?

YesNo

Edit page Report issue

On this page

Overview

Heuristics

JavaScript detections

Machine Learning (Business and Enterprise)

Anomaly detection (Enterprise)

Notes on detection

Edit page Report issue

Getting started
Plans Contact sales Partners Find a partner Startups Under attack?Domain name search

Company
AboutCareersInvestorsPressPress kitGlobal network

Public interest
Project GalileoAthenian ProjectCloudflare for CampaignsProject FairshotImpact/ESG

Compliance
Compliance resourcesTrust HubData ProtectionResponsible AITransparency reportReport abuse

Resources
App innovation reportCloudflare RadarCase studiesStatusSupportEventsBlog

Developers
DocumentationLearning centerCommunity

Solutions
SSE and SASE platformCloudflare AI CloudAI SecurityFrontend Development PlatformMulti-Tenant Platform DevelopmentWeb Security Platform

Start BuildingLog In

© 2026 Cloudflare, Inc.

Privacy policy|Report security issues|Terms of use|Trademark
|
Your privacy choices

Docs

------
导航页打开网址