diff --git a/CHANGELOG.md b/CHANGELOG.md
index b5b6e83c67..cc4dcd3fac 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 - Update resteasy to version 4.5.2.Final
+- Use browser build in EventSource for apiClient subscriptions
+
+### Removed
+- EventSource Polyfill
 
 ## 2.0.0-rc5 - 2020-03-12
 ### Added
diff --git a/scm-ui/ui-components/package.json b/scm-ui/ui-components/package.json
index 3864805706..e60bbfdea3 100644
--- a/scm-ui/ui-components/package.json
+++ b/scm-ui/ui-components/package.json
@@ -49,7 +49,6 @@
     "@scm-manager/ui-types": "^2.0.0-SNAPSHOT",
     "classnames": "^2.2.6",
     "date-fns": "^2.4.1",
-    "event-source-polyfill": "^1.0.9",
     "gitdiff-parser": "^0.1.2",
     "lowlight": "^1.13.0",
     "query-string": "5",
diff --git a/scm-ui/ui-components/src/apiclient.ts b/scm-ui/ui-components/src/apiclient.ts
index c8990b000c..f7e32f46ef 100644
--- a/scm-ui/ui-components/src/apiclient.ts
+++ b/scm-ui/ui-components/src/apiclient.ts
@@ -1,6 +1,4 @@
 import { contextPath } from "./urls";
-// @ts-ignore we have not types for event-source-polyfill
-import { EventSourcePolyfill } from "event-source-polyfill";
 import { createBackendError, ForbiddenError, isBackendError, UnauthorizedError, BackendErrorContent } from "./errors";
 
 type SubscriptionEvent = {
@@ -124,6 +122,10 @@ export function createUrl(url: string) {
   return `${contextPath}/api/v2${urlWithStartingSlash}`;
 }
 
+export function createUrlWithIdentifiers(url: string): string {
+  return createUrl(url) + "?X-SCM-Client=WUI&X-SCM-Session-ID=" + sessionId;
+}
+
 class ApiClient {
   get(url: string): Promise<Response> {
     return fetch(createUrl(url), applyFetchOptions({})).then(handleFailure);
@@ -218,9 +220,8 @@ class ApiClient {
   }
 
   subscribe(url: string, argument: SubscriptionArgument): Cancel {
-    const es = new EventSourcePolyfill(createUrl(url), {
-      withCredentials: true,
-      headers: createRequestHeaders()
+    const es = new EventSource(createUrlWithIdentifiers(url), {
+      withCredentials: true
     });
 
     let listeners: MessageListeners;
@@ -228,9 +229,11 @@ class ApiClient {
     if ("onMessage" in argument) {
       listeners = (argument as SubscriptionContext).onMessage;
       if (argument.onError) {
+        // @ts-ignore typing of EventSource is weird
         es.onerror = argument.onError;
       }
       if (argument.onOpen) {
+        // @ts-ignore typing of EventSource is weird
         es.onopen = argument.onOpen;
       }
     } else {
@@ -238,6 +241,7 @@ class ApiClient {
     }
 
     for (const type in listeners) {
+      // @ts-ignore typing of EventSource is weird
       es.addEventListener(type, listeners[type]);
     }
 
diff --git a/yarn.lock b/yarn.lock
index 42d56ee047..a2d1ea2670 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -6580,11 +6580,6 @@ etag@~1.8.1:
   resolved "https://registry.yarnpkg.com/etag/-/etag-1.8.1.tgz#41ae2eeb65efa62268aebfea83ac7d79299b0887"
   integrity sha1-Qa4u62XvpiJorr/qg6x9eSmbCIc=
 
-event-source-polyfill@^1.0.9:
-  version "1.0.12"
-  resolved "https://registry.yarnpkg.com/event-source-polyfill/-/event-source-polyfill-1.0.12.tgz#38546c4fee76dcadae2560185610ae46c5a39520"
-  integrity sha512-WjOTn0LIbaN08z/8gNt3GYAomAdm6cZ2lr/QdvhTTEipr5KR6lds2ziUH+p/Iob4Lk6NClKhwPOmn1NjQEcJCg==
-
 eventemitter3@^3.1.0:
   version "3.1.2"
   resolved "https://registry.yarnpkg.com/eventemitter3/-/eventemitter3-3.1.2.tgz#2d3d48f9c346698fce83a85d7d664e98535df6e7"