isbot

What is isbot?

The 'isbot' npm package is a lightweight utility for detecting bots, crawlers, and spiders based on the user agent string. It helps developers identify non-human traffic to their websites or applications.

What are isbot's main functionalities?

Basic Bot Detection

This feature allows you to check if a given user agent string belongs to a bot. The function returns true if the user agent is identified as a bot, otherwise false.

const isBot = require('isbot');

const userAgent = 'Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)';
console.log(isBot(userAgent)); // true

Custom Bot Patterns

You can extend the default bot detection patterns with custom patterns. This is useful if you have specific bots that are not covered by the default list.

const isBot = require('isbot');

isBot.extend(['my-custom-bot']);
const userAgent = 'my-custom-bot';
console.log(isBot(userAgent)); // true

Bot Detection in HTTP Requests

This feature demonstrates how to use 'isbot' to detect bots in incoming HTTP requests. Depending on whether the user agent is a bot, the server responds with a different message.

const isBot = require('isbot');
const http = require('http');

http.createServer((req, res) => {
  if (isBot(req.headers['user-agent'])) {
    res.writeHead(200, { 'Content-Type': 'text/plain' });
    res.end('Hello, bot!');
  } else {
    res.writeHead(200, { 'Content-Type': 'text/plain' });
    res.end('Hello, human!');
  }
}).listen(3000);

Other packages similar to isbot

useragent

The 'useragent' package provides detailed parsing of user agent strings, including bot detection. It offers more comprehensive information about the user agent, such as browser, version, and OS, but may be more complex to use compared to 'isbot'.

express-useragent

The 'express-useragent' package is an Express middleware for parsing user agent strings. It includes bot detection and provides additional details about the user agent. It is specifically designed for use with Express.js applications.

ua-parser-js

The 'ua-parser-js' package is a JavaScript library for parsing user agent strings. It includes bot detection and provides detailed information about the browser, engine, OS, and device. It is a more general-purpose library compared to 'isbot'.

README

isbot 🤖/👨‍🦰

Recognise bots/crawlers/spiders using the user agent string.

Usage

import { isbot } from "isbot";

// Nodejs HTTP
isbot(request.getHeader("User-Agent"));

// ExpressJS
isbot(req.get("user-agent"));

// Browser
isbot(navigator.userAgent);

// User Agent string
isbot(
  "Mozilla/5.0 (iPhone; CPU iPhone OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5376e Safari/8536.25 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)",
); // true

isbot(
  "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36",
); // false

Using JSDeliver CDN you can import an iife script

See specific versions https://www.jsdelivr.com/package/npm/isbot or https://cdn.jsdelivr.net/npm/isbot

<script src="https://cdn.jsdelivr.net/npm/isbot@4"></script>
// isbot is global isbot(navigator.userAgent)

How isbot maintains accuracy

isbot's prized possession is the accurate identification of bots using a regular expression. It uses expansive and regularly updated lists of user agent strings to create a regular expression that matches bots and only bots.

This is done by using a lookbehind pattern which is not supported in all environments. A fallback is provided for environments that do not support lookbehind which is less accurate. The test suite includes a percentage of false positives and false negatives which is deemed acceptable for the fallback: 1% false positive and 75% bot coverage.

All named imports

import	Type	Description
isbot	(userAgent: string): boolean	Check if the user agent is a bot
isbotNaive	(userAgent: string): boolean	Check if the user agent is a bot using a naive pattern (less accurate)
pattern	RegExp	The regular expression used to identify bots
list	string[]	List of all individual pattern parts
isbotMatch	(userAgent: string): string | null	The substring matched by the regular expression
isbotMatches	(userAgent: string): string[]	All substrings matched by the regular expression
isbotPattern	(userAgent: string): string | null	The regular expression used to identify bot substring in the user agent
isbotPatterns	(userAgent: string): string[]	All regular expressions used to identify bot substrings in the user agent
createIsbot	(pattern: RegExp): (userAgent: string): boolean	Create a custom isbot function
createIsbotFromList	(list: string): (userAgent: string): boolean	Create a custom isbot function from a list of string representation patterns

Example usages of helper functions

Create a custom isbot that does not consider Chrome Lighthouse user agent as bots.

import { createIsbotFromList, isbotMatches, list } from "isbot";

const ChromeLighthouseUserAgentStrings: string[] = [
  "mozilla/5.0 (macintosh; intel mac os x 10_15_7) applewebkit/537.36 (khtml, like gecko) chrome/94.0.4590.2 safari/537.36 chrome-lighthouse",
  "mozilla/5.0 (linux; android 7.0; moto g (4)) applewebkit/537.36 (khtml, like gecko) chrome/94.0.4590.2 mobile safari/537.36 chrome-lighthouse",
];
const patternsToRemove: Set<string> = new Set(
  ChromeLighthouseUserAgentStrings.map(isbotMatches).flat(),
);
const isbot = createIsbotFromList(
  list.filter((record) => patternsToRemove.has(record) === false),
);

Create a custom isbot that considers another pattern as a bot, which is not included in the package originally.

import { createIsbotFromList, list } from "isbot";

const isbot = createIsbotFromList(list.concat("shmulik"));

Definitions

• Bot. Autonomous program imitating or replacing some aspect of a human behaviour, performing repetitive tasks much faster than human users could.
• Good bot. Automated programs who visit websites in order to collect useful information. Web crawlers, site scrapers, stress testers, preview builders and other programs are welcomed on most websites because they serve purposes of mutual benefits.
• Bad bot. Programs which are designed to perform malicious actions, ultimately hurting businesses. Testing credential databases, DDoS attacks, spam bots.

Clarifications

What does "isbot" do?

This package aims to identify "Good bots". Those who voluntarily identify themselves by setting a unique, preferably descriptive, user agent, usually by setting a dedicated request header.

What doesn't "isbot" do?

It does not try to recognise malicious bots or programs disguising themselves as real users.

Why would I want to identify good bots?

Recognising good bots such as web crawlers is useful for multiple purposes. Although it is not recommended to serve different content to web crawlers like Googlebot, you can still elect to

• Flag pageviews to consider with business analysis.
• Prefer to serve cached content and relieve service load.
• Omit third party solutions' code (tags, pixels) and reduce costs.

  It is not recommended to whitelist requests for any reason based on user agent header only. Instead other methods of identification can be added such as reverse dns lookup.

Data sources

We use external data sources on top of our own lists to keep up to date

Crawlers user agents

• user-agents.net
• monperrus/crawler-user-agents
• Kikobeats/top-crawler-agents
• myip.ms
• matomo.org
• A Manual list

Non bot user agents

• user-agents npm package
• A Manual list

Missing something? Please open an issue

Major releases breaking changes (full changelog)

Version 4

Remove isbot function default export in favour of a named export.

import { isbot } from "isbot";

Version 3

Remove testing for node 6 and 8

Version 2

Change return value for isbot: true instead of matched string

Version 1

No functional change

Real world data

Execution times in milliseconds