diff --git a/packages/browser/package.json b/packages/browser/package.json
index 3d286c2c9c64..5fc1c5337c92 100644
--- a/packages/browser/package.json
+++ b/packages/browser/package.json
@@ -19,7 +19,8 @@
     "@sentry/core": "5.6.2",
     "@sentry/types": "5.6.1",
     "@sentry/utils": "5.6.1",
-    "tslib": "^1.9.3"
+    "tslib": "^1.9.3",
+    "localforage": "1.7.3"
   },
   "devDependencies": {
     "@types/md5": "2.1.33",
diff --git a/packages/browser/src/integrations/index.ts b/packages/browser/src/integrations/index.ts
index 21a076b636f8..9afd53c80f2c 100644
--- a/packages/browser/src/integrations/index.ts
+++ b/packages/browser/src/integrations/index.ts
@@ -3,3 +3,4 @@ export { TryCatch } from './trycatch';
 export { Breadcrumbs } from './breadcrumbs';
 export { LinkedErrors } from './linkederrors';
 export { UserAgent } from './useragent';
+export { Offline } from './offline';
diff --git a/packages/browser/src/integrations/offline.ts b/packages/browser/src/integrations/offline.ts
new file mode 100644
index 000000000000..8bc0ef7d2434
--- /dev/null
+++ b/packages/browser/src/integrations/offline.ts
@@ -0,0 +1,116 @@
+import { addGlobalEventProcessor, getCurrentHub } from '@sentry/core';
+import { Event, Integration } from '@sentry/types';
+import localforage from 'localforage';
+
+import { captureEvent } from '../index';
+
+/**
+ * store errors occuring offline and send them when online again
+ */
+export class Offline implements Integration {
+  /**
+   * @inheritDoc
+   */
+  public readonly name: string = Offline.id;
+
+  /**
+   * @inheritDoc
+   */
+  public static id: string = 'Offline';
+
+  /**
+   * the key to store the offline event queue
+   */
+  private readonly _storrageKey: string = 'offlineEventStore';
+
+  public offlineEventStore: LocalForage;
+
+  /**
+   * @inheritDoc
+   */
+  public setupOnce(): void {
+    addGlobalEventProcessor(async (event: Event) => {
+      const self = getCurrentHub().getIntegration(Offline);
+      if (self) {
+        if (navigator.onLine) {
+          return event;
+        }
+        await this._storeEvent(event);
+        return null;
+        // self._storeEvent(event);
+      }
+      return event;
+    });
+  }
+
+  public constructor() {
+    this.offlineEventStore = localforage.createInstance({
+      name: 'sentryOfflineEventStore',
+    });
+    window.addEventListener('online', () => {
+      this._drainQueue().catch(function(): void {
+        // TODO: handle rejected promise
+      });
+    });
+  }
+
+  /**
+   * store an event
+   * @param event an event
+   */
+  private async _storeEvent(event: Event): Promise<void> {
+    const storrageKey = this._storrageKey;
+    const offlineEventStore = this.offlineEventStore;
+    const promise: Promise<void> = new Promise(async function(resolve: () => void, reject: () => void): Promise<void> {
+      let queue: Event[] = [];
+      const value = await offlineEventStore.getItem(storrageKey);
+      // .then(function(value: unknown): void {
+      // })
+      // .catch(function(err: Error): void {
+      //   console.log(err);
+      // });
+      if (typeof value === 'string') {
+        queue = JSON.parse(value);
+      }
+      queue.push(event);
+      await offlineEventStore.setItem(storrageKey, JSON.stringify(queue)).catch(function(): void {
+        // reject promise because saving to the localForge store did not work
+        reject();
+      });
+      resolve();
+    });
+    return promise;
+  }
+
+  /**
+   * capture all events in the queue
+   */
+  private async _drainQueue(): Promise<void> {
+    const storrageKey = this._storrageKey;
+    const offlineEventStore = this.offlineEventStore;
+    const promise: Promise<void> = new Promise(async function(resolve: () => void, reject: () => void): Promise<void> {
+      let queue: Event[] = [];
+      // get queue
+      const value = await offlineEventStore.getItem(storrageKey).catch(function(): void {
+        // could not get queue from localForge, TODO: how to handle error?
+      });
+      // TODO: check if value in localForge can be converted with JSON.parse
+      if (typeof value === 'string') {
+        queue = JSON.parse(value);
+      }
+      await offlineEventStore.removeItem(storrageKey).catch(function(): void {
+        // could not remove queue from localForge
+        reject();
+      });
+      // process all events in the queue
+      while (queue.length > 0) {
+        const event = queue.pop();
+        if (typeof event !== 'undefined') {
+          captureEvent(event);
+        }
+      }
+      resolve();
+    });
+    return promise;
+  }
+}
diff --git a/packages/browser/src/sdk.ts b/packages/browser/src/sdk.ts
index 5328a23a6425..e06e69ad63a6 100644
--- a/packages/browser/src/sdk.ts
+++ b/packages/browser/src/sdk.ts
@@ -4,7 +4,7 @@ import { getGlobalObject } from '@sentry/utils';
 import { BrowserOptions } from './backend';
 import { BrowserClient, ReportDialogOptions } from './client';
 import { wrap as internalWrap } from './helpers';
-import { Breadcrumbs, GlobalHandlers, LinkedErrors, TryCatch, UserAgent } from './integrations';
+import { Breadcrumbs, GlobalHandlers, LinkedErrors, Offline, TryCatch, UserAgent } from './integrations';
 
 export const defaultIntegrations = [
   new CoreIntegrations.InboundFilters(),
@@ -14,6 +14,7 @@ export const defaultIntegrations = [
   new GlobalHandlers(),
   new LinkedErrors(),
   new UserAgent(),
+  new Offline(),
 ];
 
 /**
diff --git a/packages/browser/tsconfig.build.json b/packages/browser/tsconfig.build.json
index a263a085c70a..f93bd2173a6d 100644
--- a/packages/browser/tsconfig.build.json
+++ b/packages/browser/tsconfig.build.json
@@ -2,7 +2,11 @@
   "extends": "../../tsconfig.json",
   "compilerOptions": {
     "baseUrl": ".",
-    "outDir": "dist"
+    "outDir": "./dist"
   },
-  "include": ["src/**/*"]
+  "include": ["src/**/*"],
+  "exclude": [
+    "build/**/*",
+    "dist/**/*"
+  ]
 }
diff --git a/packages/browser/tsconfig.json b/packages/browser/tsconfig.json
index 15c1a0af3c44..2fc2ab23c61b 100644
--- a/packages/browser/tsconfig.json
+++ b/packages/browser/tsconfig.json
@@ -4,6 +4,8 @@
   "exclude": ["dist"],
   "compilerOptions": {
     "rootDir": ".",
-    "types": ["node", "mocha", "chai", "sinon"]
+    "types": ["node", "mocha", "chai", "sinon"],
+    "esModuleInterop": true,
+    "allowSyntheticDefaultImports": true
   }
 }
diff --git a/tsconfig.json b/tsconfig.json
index 154bca11059f..e343cafc52d5 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -7,6 +7,8 @@
       "@sentry/*": ["*/src"],
       "raven-js": ["raven-js/src/singleton.js"],
       "raven-node": ["raven-node/lib/client.js"]
-    }
+    },
+    "allowSyntheticDefaultImports": true,
+    "esModuleInterop": true
   }
 }
diff --git a/yarn.lock b/yarn.lock
index 2044db0bac4b..847755dd6320 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5490,6 +5490,11 @@ ignore@^3.3.5:
   resolved "https://registry.yarnpkg.com/ignore/-/ignore-3.3.10.tgz#0a97fb876986e8081c631160f8f9f389157f0043"
   integrity sha512-Pgs951kaMm5GXP7MOvxERINe3gsaVjUWFm+UZPSq9xYriQAksyhg0csnS0KXSNRD5NmNdapXEpjxG49+AKh/ug==
 
+immediate@~3.0.5:
+  version "3.0.6"
+  resolved "https://registry.yarnpkg.com/immediate/-/immediate-3.0.6.tgz#9db1dbd0faf8de6fbe0f5dd5e56bb606280de69b"
+  integrity sha1-nbHb0Pr43m++D13V5Wu2BigN5ps=
+
 import-fresh@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/import-fresh/-/import-fresh-2.0.0.tgz#d81355c15612d386c61f9ddd3922d4304822a546"
@@ -6940,6 +6945,13 @@ libnpmpublish@^1.1.1:
     semver "^5.5.1"
     ssri "^6.0.1"
 
+lie@3.1.1:
+  version "3.1.1"
+  resolved "https://registry.yarnpkg.com/lie/-/lie-3.1.1.tgz#9a436b2cc7746ca59de7a41fa469b3efb76bd87e"
+  integrity sha1-mkNrLMd0bKWd56QfpGmz77dr2H4=
+  dependencies:
+    immediate "~3.0.5"
+
 load-json-file@^1.0.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/load-json-file/-/load-json-file-1.1.0.tgz#956905708d58b4bab4c2261b04f59f31c99374c0"
@@ -6973,6 +6985,13 @@ loader-utils@^1.1.0:
     emojis-list "^2.0.0"
     json5 "^0.5.0"
 
+localforage@1.7.3:
+  version "1.7.3"
+  resolved "https://registry.yarnpkg.com/localforage/-/localforage-1.7.3.tgz#0082b3ca9734679e1bd534995bdd3b24cf10f204"
+  integrity sha512-1TulyYfc4udS7ECSBT2vwJksWbkwwTX8BzeUIiq8Y07Riy7bDAAnxDaPU/tWyOVmQAcWJIEIFP9lPfBGqVoPgQ==
+  dependencies:
+    lie "3.1.1"
+
 locate-path@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/locate-path/-/locate-path-2.0.0.tgz#2b568b265eec944c6d9c0de9c3dbbbca0354cd8e"