diff --git a/packages/backend/src/core/QueueService.ts b/packages/backend/src/core/QueueService.ts
index 3edb9dcab9..6cc6008567 100644
--- a/packages/backend/src/core/QueueService.ts
+++ b/packages/backend/src/core/QueueService.ts
@@ -17,6 +17,7 @@ import { bindThis } from '@/decorators.js';
 import type { Antenna } from '@/server/api/endpoints/i/import-antennas.js';
 import { ApRequestCreator } from '@/core/activitypub/ApRequestService.js';
 import { type SystemWebhookPayload } from '@/core/SystemWebhookService.js';
+import { MiNote } from '@/models/Note.js';
 import { type UserWebhookPayload } from './UserWebhookService.js';
 import type {
 	DbJobData,
@@ -40,7 +41,6 @@ import type {
 } from './QueueModule.js';
 import type httpSignature from '@peertube/http-signature';
 import type * as Bull from 'bullmq';
-import { MiNote } from '@/models/Note.js';
 
 export const QUEUE_TYPES = [
 	'system',
@@ -231,6 +231,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: activity.id ? {
+				id: activity.id,
+			} : undefined,
 		});
 	}
 
@@ -247,6 +250,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: user.id,
+			},
 		});
 	}
 
@@ -263,6 +269,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: user.id,
+			},
 		});
 	}
 
@@ -273,6 +282,9 @@ export class QueueService {
 		}, {
 			removeOnComplete: true,
 			removeOnFail: true,
+			deduplication: {
+				id: user.id,
+			},
 		});
 	}
 
@@ -289,6 +301,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: user.id,
+			},
 		});
 	}
 
@@ -305,6 +320,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: user.id,
+			},
 		});
 	}
 
@@ -321,6 +339,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: user.id,
+			},
 		});
 	}
 
@@ -339,6 +360,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: user.id,
+			},
 		});
 	}
 
@@ -355,6 +379,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: user.id,
+			},
 		});
 	}
 
@@ -371,6 +398,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: user.id,
+			},
 		});
 	}
 
@@ -387,6 +417,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: user.id,
+			},
 		});
 	}
 
@@ -403,6 +436,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: user.id,
+			},
 		});
 	}
 
@@ -421,6 +457,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: `${user.id}_${fileId}_${withReplies ?? false}`,
+			},
 		});
 	}
 
@@ -433,6 +472,9 @@ export class QueueService {
 		}, {
 			removeOnComplete: true,
 			removeOnFail: true,
+			deduplication: {
+				id: `${user.id}_${fileId}_${type ?? null}`,
+			},
 		});
 	}
 
@@ -492,6 +534,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: `${user.id}_${fileId}`,
+			},
 		});
 	}
 
@@ -509,6 +554,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: `${user.id}_${fileId}`,
+			},
 		});
 	}
 
@@ -554,6 +602,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: `${user.id}_${fileId}`,
+			},
 		});
 	}
 
@@ -571,14 +622,18 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: `${user.id}_${fileId}`,
+			},
 		});
 	}
 
 	@bindThis
-	public createImportAntennasJob(user: ThinUser, antenna: Antenna) {
+	public createImportAntennasJob(user: ThinUser, antenna: Antenna, fileId: MiDriveFile['id']) {
 		return this.dbQueue.add('importAntennas', {
 			user: { id: user.id },
 			antenna,
+			fileId,
 		}, {
 			removeOnComplete: {
 				age: 3600 * 24 * 7, // keep up to 7 days
@@ -588,6 +643,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: `${user.id}_${fileId}`,
+			},
 		});
 	}
 
@@ -605,6 +663,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: user.id,
+			},
 		});
 	}
 
@@ -663,6 +724,9 @@ export class QueueService {
 					count: 100,
 				},
 				...opts,
+				deduplication: {
+					id: `${data.from.id}_${data.to.id}_${data.requestId ?? ''}_${data.silent ?? false}_${data.withReplies ?? false}`,
+				},
 			},
 		};
 	}
@@ -680,6 +744,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: key,
+			},
 		});
 	}
 
@@ -697,6 +764,9 @@ export class QueueService {
 				age: 3600 * 24 * 7, // keep up to 7 days
 				count: 100,
 			},
+			deduplication: {
+				id: `${olderThanSeconds}_${keepFilesInUse}`,
+			},
 		});
 	}
 
diff --git a/packages/backend/src/core/activitypub/ApRendererService.ts b/packages/backend/src/core/activitypub/ApRendererService.ts
index 345b8c6ddb..a13abc6369 100644
--- a/packages/backend/src/core/activitypub/ApRendererService.ts
+++ b/packages/backend/src/core/activitypub/ApRendererService.ts
@@ -750,9 +750,11 @@ export class ApRendererService {
 	}
 
 	@bindThis
-	public renderUpdate(object: string | IObject, user: { id: MiUser['id'] }): IUpdate {
+	public renderUpdate(object: IObject, user: { id: MiUser['id'] }): IUpdate {
+		// Deterministic activity IDs to allow de-duplication by remote instances
+		const updatedAt = object.updated ? new Date(object.updated).getTime() : Date.now();
 		return {
-			id: `${this.config.url}/users/${user.id}#updates/${new Date().getTime()}`,
+			id: `${this.config.url}/users/${user.id}#updates/${updatedAt}`,
 			actor: this.userEntityService.genLocalUserUri(user.id),
 			type: 'Update',
 			to: ['https://www.w3.org/ns/activitystreams#Public'],
diff --git a/packages/backend/src/core/activitypub/type.ts b/packages/backend/src/core/activitypub/type.ts
index e86495c03e..21434f23e0 100644
--- a/packages/backend/src/core/activitypub/type.ts
+++ b/packages/backend/src/core/activitypub/type.ts
@@ -28,8 +28,9 @@ export interface IObject {
 	inReplyTo?: any;
 	replies?: ICollection | IOrderedCollection | string;
 	content?: string | null;
-	startTime?: Date;
-	endTime?: Date;
+	startTime?: Date; // TODO these are wrong - should be string
+	endTime?: Date; // TODO these are wrong - should be string
+	updated?: string;
 	icon?: any;
 	image?: any;
 	mediaType?: string;
@@ -216,7 +217,6 @@ export interface IPost extends IObject {
 	quoteUrl?: string;
 	quoteUri?: string;
 	quote?: string;
-	updated?: string;
 }
 
 export interface IQuestion extends IObject {
diff --git a/packages/backend/src/queue/processors/ImportAntennasProcessorService.ts b/packages/backend/src/queue/processors/ImportAntennasProcessorService.ts
index 35e31b9533..0fca613f29 100644
--- a/packages/backend/src/queue/processors/ImportAntennasProcessorService.ts
+++ b/packages/backend/src/queue/processors/ImportAntennasProcessorService.ts
@@ -11,8 +11,8 @@ import Logger from '@/logger.js';
 import type { AntennasRepository, UsersRepository } from '@/models/_.js';
 import { DI } from '@/di-symbols.js';
 import { bindThis } from '@/decorators.js';
-import { QueueLoggerService } from '../QueueLoggerService.js';
 import { NotificationService } from '@/core/NotificationService.js';
+import { QueueLoggerService } from '../QueueLoggerService.js';
 import { DBAntennaImportJobData } from '../types.js';
 import type * as Bull from 'bullmq';
 
@@ -79,7 +79,7 @@ export class ImportAntennasProcessorService {
 			return;
 		}
 
-		this.logger.debug(`Importing blocking of ${job.data.user.id} ...`);
+		this.logger.debug(`Importing antennas of ${job.data.user.id} ...`);
 
 		const now = new Date();
 		try {
diff --git a/packages/backend/src/queue/types.ts b/packages/backend/src/queue/types.ts
index 79ab68ab1d..6dc9f88034 100644
--- a/packages/backend/src/queue/types.ts
+++ b/packages/backend/src/queue/types.ts
@@ -110,6 +110,7 @@ export type DbNoteImportJobData = {
 export type DBAntennaImportJobData = {
 	user: ThinUser,
 	antenna: Antenna
+	fileId: MiDriveFile['id'];
 };
 
 export type DbUserImportToDbJobData = {
diff --git a/packages/backend/src/server/api/endpoints/i/import-antennas.ts b/packages/backend/src/server/api/endpoints/i/import-antennas.ts
index 9b45923e92..8db4367ad9 100644
--- a/packages/backend/src/server/api/endpoints/i/import-antennas.ts
+++ b/packages/backend/src/server/api/endpoints/i/import-antennas.ts
@@ -83,7 +83,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> {
 			if (currentAntennasCount + antennas.length >= (await this.roleService.getUserPolicies(me.id)).antennaLimit) {
 				throw new ApiError(meta.errors.tooManyAntennas);
 			}
-			this.queueService.createImportAntennasJob(me, antennas);
+			await this.queueService.createImportAntennasJob(me, antennas, file.id);
 		});
 	}
 }