diff --git a/libs/common/src/abstractions/api.service.ts b/libs/common/src/abstractions/api.service.ts
index 44b5e34a4a4..8e26707a88f 100644
--- a/libs/common/src/abstractions/api.service.ts
+++ b/libs/common/src/abstractions/api.service.ts
@@ -451,8 +451,9 @@ export abstract class ApiService {
    * Posts events for a user
    * @param request The array of events to upload
    * @param userId The optional user id the events belong to. If no user id is provided the active user id is used.
+   * @returns The list of events that failed to upload, or an empty array if all events were uploaded successfully.
    */
-  postEventsCollect: (request: EventRequest[], userId?: UserId) => Promise<any>;
+  postEventsCollect: (request: EventRequest[], userId?: UserId) => Promise<EventRequest[]>;
 
   deleteSsoUser: (organizationId: string) => Promise<void>;
   getSsoUserIdentifier: () => Promise<string>;
diff --git a/libs/common/src/platform/misc/utils.spec.ts b/libs/common/src/platform/misc/utils.spec.ts
index 818138863fb..9a850be7ac2 100644
--- a/libs/common/src/platform/misc/utils.spec.ts
+++ b/libs/common/src/platform/misc/utils.spec.ts
@@ -775,4 +775,42 @@ describe("Utils Service", () => {
       });
     });
   });
+
+  describe("chunkArray", () => {
+    it("handles empty array", () => {
+      const result = Utils.chunkArray([], 3);
+      expect(result).toEqual([]);
+    });
+
+    it("handles null array", () => {
+      const result = Utils.chunkArray(null!, 3);
+      expect(result).toEqual([]);
+    });
+
+    it.each([0, -1, null!])("handles errors on invalid chunk sizes", (chunkSize: number) => {
+      expect(() => Utils.chunkArray([1, 2, 3], chunkSize)).toThrow(
+        `Chunk size must be greater than 0`,
+      );
+    });
+
+    it("handles chunk size of 1", () => {
+      const result = Utils.chunkArray([1, 2, 3], 1);
+      expect(result).toEqual([[1], [2], [3]]);
+    });
+
+    it("handles chunk size equal to array length", () => {
+      const result = Utils.chunkArray([1, 2, 3], 3);
+      expect(result).toEqual([[1, 2, 3]]);
+    });
+
+    it("handles chunk size greater than array length", () => {
+      const result = Utils.chunkArray([1, 2, 3], 5);
+      expect(result).toEqual([[1, 2, 3]]);
+    });
+
+    it("handles chunk size less than array length", () => {
+      const result = Utils.chunkArray([1, 2, 3, 4, 5], 2);
+      expect(result).toEqual([[1, 2], [3, 4], [5]]);
+    });
+  });
 });
diff --git a/libs/common/src/platform/misc/utils.ts b/libs/common/src/platform/misc/utils.ts
index b3c1db91806..443477a419c 100644
--- a/libs/common/src/platform/misc/utils.ts
+++ b/libs/common/src/platform/misc/utils.ts
@@ -6,7 +6,7 @@ import * as path from "path";
 import { Buffer as BufferLib } from "buffer/";
 import { Observable, of, switchMap } from "rxjs";
 import { getHostname, parse } from "tldts";
-import { Merge } from "type-fest";
+import { Merge, NonNegative } from "type-fest";
 
 // This import has been flagged as unallowed for this class. It may be involved in a circular dependency loop.
 // eslint-disable-next-line no-restricted-imports
@@ -621,6 +621,21 @@ export class Utils {
 
     return null;
   }
+
+  static chunkArray<T>(a: T[], chunkSize: NonNegative<number>): T[][] {
+    if (chunkSize <= 0) {
+      throw new Error("Chunk size must be greater than 0");
+    }
+    if (a == null || a.length === 0) {
+      return [];
+    }
+
+    const res = [];
+    for (let i = 0; i < a.length; i += chunkSize) {
+      res.push(a.slice(i, i + chunkSize));
+    }
+    return res;
+  }
 }
 
 Utils.init();
diff --git a/libs/common/src/services/api.service.ts b/libs/common/src/services/api.service.ts
index 1971cd86363..7c2e18009f9 100644
--- a/libs/common/src/services/api.service.ts
+++ b/libs/common/src/services/api.service.ts
@@ -1407,7 +1407,7 @@ export class ApiService implements ApiServiceAbstraction {
     return new ListResponse(r, EventResponse);
   }
 
-  async postEventsCollect(request: EventRequest[], userId?: UserId): Promise<any> {
+  async postEventsCollect(requests: EventRequest[], userId?: UserId): Promise<EventRequest[]> {
     const authHeader = await this.tokenService.getAccessToken(userId);
     const headers = new Headers({
       "Device-Type": this.deviceType,
@@ -1418,18 +1418,37 @@ export class ApiService implements ApiServiceAbstraction {
       headers.set("User-Agent", this.customUserAgent);
     }
     const env = await firstValueFrom(this.environmentService.environment$);
-    const response = await this.fetch(
-      this.httpOperations.createRequest(env.getEventsUrl() + "/collect", {
-        cache: "no-store",
-        credentials: await this.getCredentials(),
-        method: "POST",
-        body: JSON.stringify(request),
-        headers: headers,
-      }),
-    );
-    if (response.status !== 200) {
-      return Promise.reject("Event post failed.");
-    }
+    // TODO: MDG stringify the request array into requests of no more than 50 KiB
+
+    // Break uploads into chunks of 100 events
+    let bail = false;
+    const failedRequests: EventRequest[] = [];
+    Utils.chunkArray(requests, 300).forEach(async (eventRequests) => {
+      // We only fail once per set of uploads
+      if (bail) {
+        failedRequests.push(...eventRequests);
+        return;
+      }
+
+      try {
+        const response = await this.fetch(
+          this.httpOperations.createRequest(env.getEventsUrl() + "/collect", {
+            cache: "no-store",
+            credentials: await this.getCredentials(),
+            method: "POST",
+            body: JSON.stringify(eventRequests),
+            headers: headers,
+          }),
+        );
+        if (response.status !== 200) {
+          throw new Error("Event post failed.");
+        }
+      } catch {
+        bail = true;
+        failedRequests.push(...eventRequests);
+      }
+    });
+    return failedRequests;
   }
 
   // User APIs
diff --git a/libs/common/src/services/event/event-upload.service.ts b/libs/common/src/services/event/event-upload.service.ts
index d3836a0030f..b36c89b4478 100644
--- a/libs/common/src/services/event/event-upload.service.ts
+++ b/libs/common/src/services/event/event-upload.service.ts
@@ -71,7 +71,7 @@ export class EventUploadService implements EventUploadServiceAbstraction {
     if (eventCollection == null || eventCollection.length === 0) {
       return;
     }
-    const request = eventCollection.map((e) => {
+    const eventRequests = eventCollection.map((e) => {
       const req = new EventRequest();
       req.type = e.type;
       req.cipherId = e.cipherId;
@@ -79,12 +79,26 @@ export class EventUploadService implements EventUploadServiceAbstraction {
       req.organizationId = e.organizationId;
       return req;
     });
+
+    let failedEvents: EventRequest[];
     try {
-      await this.apiService.postEventsCollect(request, userId);
+      failedEvents = await this.apiService.postEventsCollect(eventRequests, userId);
     } catch (e) {
       this.logService.error(e);
-      // Add the events back to state if there was an error and they were not uploaded.
-      await this.stateProvider.setUserState(EVENT_COLLECTION, eventCollection, userId);
+      failedEvents = eventRequests;
+    }
+
+    // Add any events that failed to upload back to state.
+    if (failedEvents && failedEvents.length > 0) {
+      const failedEventData = failedEvents.map((e) => {
+        const eventData = new EventData();
+        eventData.type = e.type;
+        eventData.cipherId = e.cipherId;
+        eventData.date = e.date;
+        eventData.organizationId = e.organizationId;
+        return eventData;
+      });
+      await this.stateProvider.setUserState(EVENT_COLLECTION, failedEventData, userId);
     }
   }