diff --git a/packages/core/src/utils.ts b/packages/core/src/utils.ts
index b81ec47a82..1c9d27e44f 100644
--- a/packages/core/src/utils.ts
+++ b/packages/core/src/utils.ts
@@ -171,10 +171,6 @@ function hasToJSON(value: unknown): value is ObjectWithToJSON {
   return typeof value === 'object' && value !== null && value.hasOwnProperty('toJSON')
 }
 
-export function startsWith(candidate: string, search: string) {
-  return candidate.indexOf(search) === 0
-}
-
 export function includes(candidate: unknown[], search: unknown) {
   return candidate.indexOf(search) !== -1
 }
diff --git a/packages/rum/src/resourceUtils.ts b/packages/rum/src/resourceUtils.ts
index edd167deff..6c9c54c7b3 100644
--- a/packages/rum/src/resourceUtils.ts
+++ b/packages/rum/src/resourceUtils.ts
@@ -1,4 +1,4 @@
-import { addMonitoringMessage, Configuration, includes, msToNs, ResourceKind, startsWith } from '@datadog/browser-core'
+import { addMonitoringMessage, Configuration, includes, msToNs, ResourceKind } from '@datadog/browser-core'
 
 import { PerformanceResourceDetails } from './rum'
 
@@ -98,5 +98,5 @@ function isBrowserAgentRequest(url: string, configuration: Configuration) {
 }
 
 function haveSameOrigin(url1: string, url2: string) {
-  return startsWith(url2, new URL(url1).origin)
+  return new URL(url1).origin === new URL(url2).origin
 }