diff --git a/src/__tests__/utils.js b/src/__tests__/utils.js
index a3ca73dfd..b60b98b70 100644
--- a/src/__tests__/utils.js
+++ b/src/__tests__/utils.js
@@ -5,7 +5,13 @@
  * currently not supported in the browser lib).
  */
 
-import { _copyAndTruncateStrings, _info, loadScript } from '../utils'
+import { _copyAndTruncateStrings, _info, _isBlockedUA, DEFAULT_BLOCKED_UA_STRS, loadScript } from '../utils'
+
+function userAgentFor(botString) {
+    const randOne = (Math.random() + 1).toString(36).substring(7)
+    const randTwo = (Math.random() + 1).toString(36).substring(7)
+    return `Mozilla/5.0 (compatible; ${botString}/${randOne}; +http://a.com/bot/${randTwo})`
+}
 
 describe(`utils.js`, () => {
     it('should have $host and $pathname in properties', () => {
@@ -208,4 +214,15 @@ describe('loadScript', () => {
         new_script.onerror('uh-oh')
         expect(callback).toHaveBeenCalledWith('uh-oh')
     })
+
+    describe('user agent blocking', () => {
+        it.each(DEFAULT_BLOCKED_UA_STRS.concat('testington'))(
+            'blocks a bot based on the user agent %s',
+            (botString) => {
+                const randomisedUserAgent = userAgentFor(botString)
+
+                expect(_isBlockedUA(randomisedUserAgent, ['testington'])).toBe(true)
+            }
+        )
+    })
 })
diff --git a/src/posthog-core.ts b/src/posthog-core.ts
index 81826d2f3..edd056947 100644
--- a/src/posthog-core.ts
+++ b/src/posthog-core.ts
@@ -114,6 +114,7 @@ const defaultConfig = (): PostHogConfig => ({
     loaded: __NOOP,
     store_google: true,
     custom_campaign_params: [],
+    custom_blocked_useragents: [],
     save_referrer: true,
     test: false,
     verbose: false,
@@ -853,7 +854,7 @@ export class PostHog {
             return
         }
 
-        if (_isBlockedUA(userAgent)) {
+        if (_isBlockedUA(userAgent, this.get_config('custom_blocked_useragents'))) {
             return
         }
 
diff --git a/src/types.ts b/src/types.ts
index e39a4f2a1..a041dc894 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -63,6 +63,10 @@ export interface PostHogConfig {
     loaded: (posthog_instance: PostHog) => void
     store_google: boolean
     custom_campaign_params: string[]
+    // a list of strings to be tested against navigator.userAgent to determine if the source is a bot
+    // this is **added to** the default list of bots that we check
+    // defaults to the empty array
+    custom_blocked_useragents: string[]
     save_referrer: boolean
     test: boolean
     verbose: boolean
diff --git a/src/utils.ts b/src/utils.ts
index 0a786882c..2ee2ab003 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -461,18 +461,60 @@ export const _utf8Encode = function (string: string): string {
     return utftext
 }
 
+export const DEFAULT_BLOCKED_UA_STRS = [
+    'ahrefsbot',
+    'applebot',
+    'baiduspider',
+    'bingbot',
+    'bingpreview',
+    'bot.htm',
+    'bot.php',
+    'crawler',
+    'duckduckbot',
+    'facebookexternal',
+    'facebookcatalog',
+    'gptbot',
+    'hubspot',
+    'linkedinbot',
+    'mj12bot',
+    'petalbot',
+    'pinterest',
+    'prerender',
+    'rogerbot',
+    'screaming frog',
+    'semrushbot',
+    'sitebulb',
+    'twitterbot',
+    'yahoo! slurp',
+    'yandexbot',
+
+    // a whole bunch of goog-specific crawlers
+    // https://developers.google.com/search/docs/advanced/crawling/overview-google-crawlers
+    'adsbot-google',
+    'apis-google',
+    'duplexweb-google',
+    'feedfetcher-google',
+    'google favicon',
+    'google web preview',
+    'google-read-aloud',
+    'googlebot',
+    'googleweblight',
+    'mediapartners-google',
+    'storebot-google',
+]
+
 // _.isBlockedUA()
 // This is to block various web spiders from executing our JS and
 // sending false capturing data
-export const _isBlockedUA = function (ua: string): boolean {
-    if (
-        /(google web preview|baiduspider|yandexbot|bingbot|googlebot|yahoo! slurp|ahrefsbot|facebookexternalhit|facebookcatalog|applebot|semrushbot|duckduckbot|twitterbot|rogerbot|linkedinbot|mj12bot|sitebulb|bot.htm|bot.php|hubspot|crawler|prerender|gptbot)/i.test(
-            ua
-        )
-    ) {
-        return true
-    }
-    return false
+export const _isBlockedUA = function (ua: string, customBlockedUserAgents: string[]): boolean {
+    return DEFAULT_BLOCKED_UA_STRS.concat(customBlockedUserAgents).some((blockedUA) => {
+        if (ua.includes) {
+            return ua.includes(blockedUA)
+        } else {
+            // IE 11 :/
+            return ua.indexOf(blockedUA) !== -1
+        }
+    })
 }
 
 /**