diff --git a/.changeset/slack-scope-message-updates.md b/.changeset/slack-scope-message-updates.md
new file mode 100644
index 0000000000..0bea25c1d8
--- /dev/null
+++ b/.changeset/slack-scope-message-updates.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-notifications-backend-module-slack': patch
+---
+
+Added scope-based message update support. When a notification is re-sent with the same `scope` and `notification.updated` is set, the processor now calls `chat.update()` on the existing Slack message instead of sending a duplicate via `chat.postMessage()`. Message timestamps are persisted in a new `slack_message_timestamps` database table with automatic daily cleanup. The processor gracefully degrades to the previous behavior when no database is provided.
diff --git a/plugins/notifications-backend-module-slack/migrations/20260327000000_create_slack_message_timestamps.js b/plugins/notifications-backend-module-slack/migrations/20260327000000_create_slack_message_timestamps.js
new file mode 100644
index 0000000000..6bddab3e54
--- /dev/null
+++ b/plugins/notifications-backend-module-slack/migrations/20260327000000_create_slack_message_timestamps.js
@@ -0,0 +1,44 @@
+// @ts-check
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @param {import('knex').Knex} knex
+ */
+exports.up = async function up(knex) {
+  await knex.schema.createTable(
+    'slack_message_timestamps',
+    function tableSetup(table) {
+      table.string('origin', 256).notNullable();
+      table.string('scope', 512).notNullable();
+      table.string('channel', 64).notNullable();
+      table.string('ts', 64).notNullable();
+      table
+        .timestamp('created_at', { useTz: true })
+        .defaultTo(knex.fn.now())
+        .notNullable();
+      table.primary(['origin', 'scope', 'channel']);
+      table.index('created_at', 'idx_slack_message_timestamps_created_at');
+    },
+  );
+};
+
+/**
+ * @param {import('knex').Knex} knex
+ */
+exports.down = async function down(knex) {
+  await knex.schema.dropTable('slack_message_timestamps');
+};
diff --git a/plugins/notifications-backend-module-slack/package.json b/plugins/notifications-backend-module-slack/package.json
index 5e4ff43bf6..8708d9e77a 100644
--- a/plugins/notifications-backend-module-slack/package.json
+++ b/plugins/notifications-backend-module-slack/package.json
@@ -22,7 +22,8 @@
   "types": "src/index.ts",
   "files": [
     "dist",
-    "config.d.ts"
+    "config.d.ts",
+    "migrations"
   ],
   "scripts": {
     "build": "backstage-cli package build",
@@ -46,6 +47,7 @@
     "@slack/types": "^2.14.0",
     "@slack/web-api": "^7.5.0",
     "dataloader": "^2.0.0",
+    "knex": "^3.0.0",
     "p-throttle": "^4.1.1"
   },
   "devDependencies": {
diff --git a/plugins/notifications-backend-module-slack/report.sql.md b/plugins/notifications-backend-module-slack/report.sql.md
new file mode 100644
index 0000000000..daff159f33
--- /dev/null
+++ b/plugins/notifications-backend-module-slack/report.sql.md
@@ -0,0 +1,18 @@
+## SQL Report file for "@backstage/plugin-notifications-backend-module-slack"
+
+> Do not edit this file. It is a report generated by `yarn build:api-reports`
+
+## Table `slack_message_timestamps`
+
+| Column       | Type                       | Nullable | Max Length | Default             |
+| ------------ | -------------------------- | -------- | ---------- | ------------------- |
+| `channel`    | `character varying`        | false    | 64         | -                   |
+| `created_at` | `timestamp with time zone` | false    | -          | `CURRENT_TIMESTAMP` |
+| `origin`     | `character varying`        | false    | 256        | -                   |
+| `scope`      | `character varying`        | false    | 512        | -                   |
+| `ts`         | `character varying`        | false    | 64         | -                   |
+
+### Indices
+
+- `idx_slack_message_timestamps_created_at` (`created_at`)
+- `slack_message_timestamps_pkey` (`origin`, `scope`, `channel`) unique primary
diff --git a/plugins/notifications-backend-module-slack/src/lib/SlackNotificationProcessor.test.ts b/plugins/notifications-backend-module-slack/src/lib/SlackNotificationProcessor.test.ts
index 0393070b3f..ddf34b6b89 100644
--- a/plugins/notifications-backend-module-slack/src/lib/SlackNotificationProcessor.test.ts
+++ b/plugins/notifications-backend-module-slack/src/lib/SlackNotificationProcessor.test.ts
@@ -20,6 +20,7 @@ import { SlackNotificationProcessor } from './SlackNotificationProcessor';
 import { catalogServiceMock } from '@backstage/plugin-catalog-node/testUtils';
 import { KnownBlock, WebClient } from '@slack/web-api';
 import { Entity } from '@backstage/catalog-model';
+import { Knex } from 'knex';
 import pThrottle from 'p-throttle';
 import { durationToMilliseconds } from '@backstage/types';
 
@@ -45,6 +46,11 @@ jest.mock('@slack/web-api', () => {
         ts: '1234567890.123456',
         channel: 'C12345678',
       })),
+      update: jest.fn(() => ({
+        ok: true,
+        ts: '1234567890.123456',
+        channel: 'C12345678',
+      })),
     },
     conversations: {
       list: jest.fn(() => ({
@@ -1615,4 +1621,382 @@ describe('SlackNotificationProcessor', () => {
       ]);
     });
   });
+
+  describe('scope-based message updates', () => {
+    function createMockDb() {
+      const store = new Map<
+        string,
+        {
+          origin: string;
+          scope: string;
+          channel: string;
+          ts: string;
+          created_at: Date;
+        }
+      >();
+
+      function storeKey(origin: string, scope: string, channel: string) {
+        return `${origin}:${scope}:${channel}`;
+      }
+
+      // Each call to db() creates a fresh query builder that tracks its own
+      // chained .where()/.insert() arguments, avoiding cross-call interference.
+      function createQueryBuilder(): any {
+        let lastWhereArgs: any;
+        let lastInsertRow: any;
+        const qb: any = {
+          where: jest.fn().mockImplementation((args: any) => {
+            lastWhereArgs = args;
+            return qb;
+          }),
+          first: jest.fn().mockImplementation(() => {
+            if (lastWhereArgs) {
+              const key = storeKey(
+                lastWhereArgs.origin,
+                lastWhereArgs.scope,
+                lastWhereArgs.channel,
+              );
+              return Promise.resolve(store.get(key));
+            }
+            return Promise.resolve(undefined);
+          }),
+          insert: jest.fn().mockImplementation((row: any) => {
+            lastInsertRow = row;
+            store.set(storeKey(row.origin, row.scope, row.channel), row);
+            return qb;
+          }),
+          onConflict: jest.fn().mockReturnThis(),
+          merge: jest.fn().mockImplementation((row: any) => {
+            if (lastInsertRow) {
+              const key = storeKey(
+                lastInsertRow.origin,
+                lastInsertRow.scope,
+                lastInsertRow.channel,
+              );
+              const existing = store.get(key);
+              if (existing) {
+                store.set(key, { ...existing, ...row });
+              }
+            }
+            return Promise.resolve();
+          }),
+          delete: jest.fn().mockResolvedValue(0),
+        };
+        return qb;
+      }
+
+      const db = jest
+        .fn()
+        .mockImplementation(() => createQueryBuilder()) as unknown as Knex;
+      (db as any).fn = { now: jest.fn().mockReturnValue(new Date()) };
+      return { db, store, storeKey };
+    }
+
+    function createProcessorWithDb(
+      slack: WebClient,
+      db: Knex,
+    ): SlackNotificationProcessor {
+      const processor = SlackNotificationProcessor.fromConfig(config, {
+        auth,
+        logger,
+        catalog: catalogServiceMock({
+          entities: DEFAULT_ENTITIES_RESPONSE.items,
+        }),
+        metrics,
+        slack,
+      })[0];
+      processor.setDatabase(db);
+      return processor;
+    }
+
+    it('should store the message timestamp after initial scoped send', async () => {
+      const slack = new WebClient();
+      const { db, store, storeKey } = createMockDb();
+      const processor = createProcessorWithDb(slack, db);
+
+      await processor.postProcess(
+        {
+          origin: 'plugin',
+          id: '1234',
+          user: 'user:default/mock',
+          created: new Date(),
+          payload: {
+            title: 'notification',
+            scope: 'deployment-failure/my-service/42',
+          },
+        },
+        {
+          recipients: { type: 'entity', entityRef: 'user:default/mock' },
+          payload: {
+            title: 'notification',
+            scope: 'deployment-failure/my-service/42',
+          },
+        },
+      );
+
+      expect(slack.chat.postMessage).toHaveBeenCalledTimes(1);
+      expect(store.size).toBe(1);
+      const key = storeKey(
+        'plugin',
+        'deployment-failure/my-service/42',
+        'U12345678',
+      );
+      expect(store.get(key)).toEqual(
+        expect.objectContaining({
+          origin: 'plugin',
+          scope: 'deployment-failure/my-service/42',
+          channel: 'U12345678',
+          ts: '1234567890.123456',
+        }),
+      );
+    });
+
+    it('should use chat.update when the notification has been updated and a stored ts exists', async () => {
+      const slack = new WebClient();
+      const { db, store, storeKey } = createMockDb();
+
+      // Pre-populate the store with a previously sent message.
+      store.set(
+        storeKey('plugin', 'deployment-failure/my-service/42', 'U12345678'),
+        {
+          origin: 'plugin',
+          scope: 'deployment-failure/my-service/42',
+          channel: 'U12345678',
+          ts: '1111111111.111111',
+          created_at: new Date(),
+        },
+      );
+
+      const processor = createProcessorWithDb(slack, db);
+
+      await processor.postProcess(
+        {
+          origin: 'plugin',
+          id: '1234',
+          user: 'user:default/mock',
+          created: new Date(),
+          updated: new Date(),
+          payload: {
+            title: 'notification',
+            description: 'Updated with analysis',
+            scope: 'deployment-failure/my-service/42',
+          },
+        },
+        {
+          recipients: { type: 'entity', entityRef: 'user:default/mock' },
+          payload: {
+            title: 'notification',
+            description: 'Updated with analysis',
+            scope: 'deployment-failure/my-service/42',
+          },
+        },
+      );
+
+      expect(slack.chat.postMessage).not.toHaveBeenCalled();
+      expect(slack.chat.update).toHaveBeenCalledTimes(1);
+
+      // Verify chat.update receives only the fields it supports (channel, ts,
+      // text, blocks, attachments) and not the full ChatPostMessageArguments.
+      const updateArgs = (slack.chat.update as jest.Mock).mock.calls[0][0];
+      const updateKeys = Object.keys(updateArgs).sort();
+      expect(updateKeys).toEqual(['attachments', 'channel', 'text', 'ts']);
+      expect(updateArgs.channel).toBe('U12345678');
+      expect(updateArgs.ts).toBe('1111111111.111111');
+    });
+
+    it('should fall back to chat.postMessage when notification is updated but no stored ts exists', async () => {
+      const slack = new WebClient();
+      const { db } = createMockDb();
+      const processor = createProcessorWithDb(slack, db);
+
+      await processor.postProcess(
+        {
+          origin: 'plugin',
+          id: '1234',
+          user: 'user:default/mock',
+          created: new Date(),
+          updated: new Date(),
+          payload: {
+            title: 'notification',
+            scope: 'deployment-failure/my-service/42',
+          },
+        },
+        {
+          recipients: { type: 'entity', entityRef: 'user:default/mock' },
+          payload: {
+            title: 'notification',
+            scope: 'deployment-failure/my-service/42',
+          },
+        },
+      );
+
+      // Should fall back to postMessage since there is no stored ts.
+      expect(slack.chat.update).not.toHaveBeenCalled();
+      expect(slack.chat.postMessage).toHaveBeenCalledTimes(1);
+    });
+
+    it('should not interact with the database for non-scoped notifications', async () => {
+      const slack = new WebClient();
+      const { db } = createMockDb();
+      const processor = createProcessorWithDb(slack, db);
+
+      await processor.postProcess(
+        {
+          origin: 'plugin',
+          id: '1234',
+          user: 'user:default/mock',
+          created: new Date(),
+          payload: {
+            title: 'notification',
+          },
+        },
+        {
+          recipients: { type: 'entity', entityRef: 'user:default/mock' },
+          payload: { title: 'notification' },
+        },
+      );
+
+      expect(slack.chat.postMessage).toHaveBeenCalledTimes(1);
+      // The db function should not have been called since there is no scope.
+      expect(db).not.toHaveBeenCalled();
+    });
+
+    it('should work without a database (graceful degradation)', async () => {
+      const slack = new WebClient();
+
+      // No db set — the processor should still send messages normally.
+      const processor = SlackNotificationProcessor.fromConfig(config, {
+        auth,
+        logger,
+        catalog: catalogServiceMock({
+          entities: DEFAULT_ENTITIES_RESPONSE.items,
+        }),
+        metrics,
+        slack,
+      })[0];
+
+      await processor.postProcess(
+        {
+          origin: 'plugin',
+          id: '1234',
+          user: 'user:default/mock',
+          created: new Date(),
+          payload: {
+            title: 'notification',
+            scope: 'deployment-failure/my-service/42',
+          },
+        },
+        {
+          recipients: { type: 'entity', entityRef: 'user:default/mock' },
+          payload: {
+            title: 'notification',
+            scope: 'deployment-failure/my-service/42',
+          },
+        },
+      );
+
+      expect(slack.chat.postMessage).toHaveBeenCalledTimes(1);
+      expect(slack.chat.update).not.toHaveBeenCalled();
+    });
+
+    it('should handle concurrent postProcess calls with different scopes correctly', async () => {
+      const slack = new WebClient();
+      const { db, store, storeKey } = createMockDb();
+
+      // Pre-populate stored timestamps for both scopes.
+      store.set(storeKey('plugin', 'scope-a', 'U12345678'), {
+        origin: 'plugin',
+        scope: 'scope-a',
+        channel: 'U12345678',
+        ts: '1111111111.111111',
+        created_at: new Date(),
+      });
+      store.set(storeKey('plugin', 'scope-b', 'U12345678'), {
+        origin: 'plugin',
+        scope: 'scope-b',
+        channel: 'U12345678',
+        ts: '2222222222.222222',
+        created_at: new Date(),
+      });
+
+      const processor = createProcessorWithDb(slack, db);
+
+      // Fire both postProcess calls concurrently with different scopes.
+      await Promise.all([
+        processor.postProcess(
+          {
+            origin: 'plugin',
+            id: '1',
+            user: 'user:default/mock',
+            created: new Date(),
+            updated: new Date(),
+            payload: { title: 'A', scope: 'scope-a' },
+          },
+          {
+            recipients: { type: 'entity', entityRef: 'user:default/mock' },
+            payload: { title: 'A', scope: 'scope-a' },
+          },
+        ),
+        processor.postProcess(
+          {
+            origin: 'plugin',
+            id: '2',
+            user: 'user:default/mock',
+            created: new Date(),
+            updated: new Date(),
+            payload: { title: 'B', scope: 'scope-b' },
+          },
+          {
+            recipients: { type: 'entity', entityRef: 'user:default/mock' },
+            payload: { title: 'B', scope: 'scope-b' },
+          },
+        ),
+      ]);
+
+      // Both should use chat.update, not postMessage.
+      expect(slack.chat.postMessage).not.toHaveBeenCalled();
+      expect(slack.chat.update).toHaveBeenCalledTimes(2);
+
+      // Each update should use the correct ts for its scope.
+      const updateCalls = (slack.chat.update as jest.Mock).mock.calls;
+      const timestamps = updateCalls.map((call: any[]) => call[0].ts).sort();
+      expect(timestamps).toEqual(['1111111111.111111', '2222222222.222222']);
+    });
+
+    it('should not collide across different origins with the same scope', async () => {
+      const slack = new WebClient();
+      const { db, store, storeKey } = createMockDb();
+
+      // Pre-populate a stored timestamp for origin-a only.
+      store.set(storeKey('origin-a', 'shared-scope', 'U12345678'), {
+        origin: 'origin-a',
+        scope: 'shared-scope',
+        channel: 'U12345678',
+        ts: '1111111111.111111',
+        created_at: new Date(),
+      });
+
+      const processor = createProcessorWithDb(slack, db);
+
+      // Send an update from origin-b with the same scope — should NOT find
+      // the stored ts from origin-a, and should fall back to postMessage.
+      await processor.postProcess(
+        {
+          origin: 'origin-b',
+          id: '1',
+          user: 'user:default/mock',
+          created: new Date(),
+          updated: new Date(),
+          payload: { title: 'From B', scope: 'shared-scope' },
+        },
+        {
+          recipients: { type: 'entity', entityRef: 'user:default/mock' },
+          payload: { title: 'From B', scope: 'shared-scope' },
+        },
+      );
+
+      expect(slack.chat.update).not.toHaveBeenCalled();
+      expect(slack.chat.postMessage).toHaveBeenCalledTimes(1);
+    });
+  });
 });
diff --git a/plugins/notifications-backend-module-slack/src/lib/SlackNotificationProcessor.ts b/plugins/notifications-backend-module-slack/src/lib/SlackNotificationProcessor.ts
index 9a95b61210..bcbce0676c 100644
--- a/plugins/notifications-backend-module-slack/src/lib/SlackNotificationProcessor.ts
+++ b/plugins/notifications-backend-module-slack/src/lib/SlackNotificationProcessor.ts
@@ -34,8 +34,13 @@ import {
   NotificationSendOptions,
 } from '@backstage/plugin-notifications-node';
 import { durationToMilliseconds } from '@backstage/types';
-import { ChatPostMessageArguments, WebClient } from '@slack/web-api';
+import {
+  ChatPostMessageArguments,
+  ChatUpdateArguments,
+  WebClient,
+} from '@slack/web-api';
 import DataLoader from 'dataloader';
+import { Knex } from 'knex';
 import pThrottle from 'p-throttle';
 import { ANNOTATION_SLACK_BOT_NOTIFY } from './constants';
 import { BroadcastRoute } from './types';
@@ -43,6 +48,12 @@ import { ExpiryMap, toChatPostMessageArgs } from './util';
 import { CatalogService } from '@backstage/plugin-catalog-node';
 import { SlackBlockKitRenderer } from '../extensions';
 
+interface ScopeContext {
+  origin: string;
+  scope?: string;
+  isUpdate?: boolean;
+}
+
 export class SlackNotificationProcessor implements NotificationProcessor {
   private readonly logger: LoggerService;
   private readonly catalog: CatalogService;
@@ -50,9 +61,12 @@ export class SlackNotificationProcessor implements NotificationProcessor {
   private readonly slack: WebClient;
   private readonly sendNotifications: (
     opts: ChatPostMessageArguments[],
+    scopeContext?: ScopeContext,
   ) => Promise<void>;
   private readonly messagesSent: MetricsServiceCounter;
   private readonly messagesFailed: MetricsServiceCounter;
+  private readonly messagesUpdated: MetricsServiceCounter;
+  private db?: Knex;
   private readonly broadcastChannels?: string[];
   private readonly broadcastRoutes?: BroadcastRoute[];
   private readonly entityLoader: DataLoader<string, Entity | undefined>;
@@ -179,25 +193,42 @@ export class SlackNotificationProcessor implements NotificationProcessor {
         unit: '{message}',
       },
     );
+    this.messagesUpdated = metrics.createCounter(
+      'notifications.processors.slack.update.count',
+      {
+        description:
+          'Number of existing Slack messages updated via scope matching',
+        unit: '{message}',
+      },
+    );
 
     const throttle = pThrottle({
       limit: this.concurrencyLimit,
       interval: this.throttleInterval,
     });
-    const throttled = throttle((opts: ChatPostMessageArguments) =>
-      this.sendNotification(opts),
+    const throttled = throttle(
+      (opts: ChatPostMessageArguments, ctx?: ScopeContext) =>
+        this.sendNotification(opts, ctx),
     );
-    this.sendNotifications = async (opts: ChatPostMessageArguments[]) => {
+    this.sendNotifications = async (
+      opts: ChatPostMessageArguments[],
+      scopeContext?: ScopeContext,
+    ) => {
       const results = await Promise.allSettled(
-        opts.map(message => throttled(message)),
+        opts.map(message => throttled(message, scopeContext)),
       );
 
-      let successCount = 0;
+      let sentCount = 0;
+      let updateCount = 0;
       let failureCount = 0;
 
       results.forEach((result, index) => {
         if (result.status === 'fulfilled') {
-          successCount++;
+          if (result.value === 'updated') {
+            updateCount++;
+          } else {
+            sentCount++;
+          }
         } else {
           this.logger.error(
             `Failed to send Slack channel notification to ${opts[index].channel}: ${result.reason.message}`,
@@ -206,11 +237,16 @@ export class SlackNotificationProcessor implements NotificationProcessor {
         }
       });
 
-      this.messagesSent.add(successCount);
+      this.messagesSent.add(sentCount);
+      this.messagesUpdated.add(updateCount);
       this.messagesFailed.add(failureCount);
     };
   }
 
+  setDatabase(db: Knex): void {
+    this.db = db;
+  }
+
   getName(): string {
     return 'SlackNotificationProcessor';
   }
@@ -335,8 +371,11 @@ export class SlackNotificationProcessor implements NotificationProcessor {
       this.logger.debug(`Sending notification: ${JSON.stringify(payload)}`);
     });
 
-    // Send notifications
-    await this.sendNotifications(outbound);
+    await this.sendNotifications(outbound, {
+      origin: notification.origin,
+      scope: notification.payload.scope,
+      isUpdate: !!notification.updated,
+    });
   }
 
   private async formatPayloadDescriptionForSlack(
@@ -432,12 +471,93 @@ export class SlackNotificationProcessor implements NotificationProcessor {
     }
   }
 
-  async sendNotification(args: ChatPostMessageArguments): Promise<void> {
+  async sendNotification(
+    args: ChatPostMessageArguments,
+    scopeContext?: ScopeContext,
+  ): Promise<'sent' | 'updated'> {
+    const channel = args.channel as string;
+    const scope = scopeContext?.scope;
+
+    // If this is a scoped update, try to update the existing Slack message.
+    const origin = scopeContext?.origin;
+    if (scopeContext?.isUpdate && origin && scope && this.db) {
+      const storedTs = await this.getStoredTimestamp(origin, scope, channel);
+      if (storedTs) {
+        const updateArgs = {
+          channel,
+          ts: storedTs,
+          ...('text' in args ? { text: args.text } : {}),
+          ...('blocks' in args ? { blocks: args.blocks } : {}),
+          ...('attachments' in args ? { attachments: args.attachments } : {}),
+        } as ChatUpdateArguments;
+        const updateResponse = await this.slack.chat.update(updateArgs);
+
+        if (!updateResponse.ok) {
+          throw new Error(
+            `Failed to update notification: ${updateResponse.error}`,
+          );
+        }
+
+        return 'updated';
+      }
+    }
+
+    // Send a new message.
     const response = await this.slack.chat.postMessage(args);
 
     if (!response.ok) {
       throw new Error(`Failed to send notification: ${response.error}`);
     }
+
+    // Persist the message timestamp for future scope-based updates.
+    if (origin && scope && response.ts && this.db) {
+      await this.saveTimestamp(origin, scope, channel, response.ts);
+    }
+
+    return 'sent';
+  }
+
+  private async getStoredTimestamp(
+    origin: string,
+    scope: string,
+    channel: string,
+  ): Promise<string | undefined> {
+    try {
+      const row = await this.db!('slack_message_timestamps')
+        .where({ origin, scope, channel })
+        .first();
+      return row?.ts;
+    } catch (error) {
+      this.logger.warn('Failed to look up stored Slack message timestamp', {
+        origin,
+        scope,
+        channel,
+        error,
+      });
+      return undefined;
+    }
+  }
+
+  private async saveTimestamp(
+    origin: string,
+    scope: string,
+    channel: string,
+    ts: string,
+  ): Promise<void> {
+    try {
+      const now = this.db!.fn.now();
+      await this.db!('slack_message_timestamps')
+        .insert({ origin, scope, channel, ts, created_at: now })
+        .onConflict(['origin', 'scope', 'channel'])
+        .merge({ ts, created_at: now });
+    } catch (error) {
+      this.logger.warn('Failed to persist Slack message timestamp', {
+        origin,
+        scope,
+        channel,
+        error,
+      });
+    }
   }
 
   private static parseBroadcastRoute(route: Config): BroadcastRoute {
diff --git a/plugins/notifications-backend-module-slack/src/module.ts b/plugins/notifications-backend-module-slack/src/module.ts
index 88f0272eb3..450d10f120 100644
--- a/plugins/notifications-backend-module-slack/src/module.ts
+++ b/plugins/notifications-backend-module-slack/src/module.ts
@@ -16,7 +16,9 @@
 import {
   coreServices,
   createBackendModule,
+  resolvePackagePath,
 } from '@backstage/backend-plugin-api';
+import { Knex } from 'knex';
 import { metricsServiceRef } from '@backstage/backend-plugin-api/alpha';
 import { notificationsProcessingExtensionPoint } from '@backstage/plugin-notifications-node';
 import { SlackNotificationProcessor } from './lib/SlackNotificationProcessor';
@@ -26,6 +28,23 @@ import {
   SlackBlockKitRenderer,
 } from './extensions';
 
+const MIGRATIONS_DIR = resolvePackagePath(
+  '@backstage/plugin-notifications-backend-module-slack',
+  'migrations',
+);
+
+const DB_MIGRATIONS_TABLE = 'notifications_module_slack__knex_migrations';
+const CLEANUP_RETENTION_SECONDS = 24 * 60 * 60; // 24 hours
+
+function nowMinus(knex: Knex, seconds: number): Knex.Raw {
+  if (knex.client.config.client.includes('sqlite3')) {
+    return knex.raw(`datetime('now', ?)`, [`-${seconds} seconds`]);
+  } else if (knex.client.config.client.includes('mysql')) {
+    return knex.raw(`now() - interval ${seconds} second`);
+  }
+  return knex.raw(`now() - interval '${seconds} seconds'`);
+}
+
 /**
  * The Slack notification processor for use with the notifications plugin.
  * This allows sending of notifications via Slack DMs or to channels.
@@ -54,17 +73,69 @@ export const notificationsModuleSlack = createBackendModule({
         catalog: catalogServiceRef,
         notifications: notificationsProcessingExtensionPoint,
         metrics: metricsServiceRef,
+        database: coreServices.database,
+        scheduler: coreServices.scheduler,
       },
-      async init({ auth, config, logger, catalog, notifications, metrics }) {
-        notifications.addProcessor(
-          SlackNotificationProcessor.fromConfig(config, {
-            auth,
-            logger,
-            catalog,
-            metrics,
-            blockKitRenderer,
-          }),
-        );
+      async init({
+        auth,
+        config,
+        logger,
+        catalog,
+        notifications,
+        metrics,
+        database,
+        scheduler,
+      }) {
+        const processors = SlackNotificationProcessor.fromConfig(config, {
+          auth,
+          logger,
+          catalog,
+          metrics,
+          blockKitRenderer,
+        });
+
+        if (processors.length === 0) {
+          return;
+        }
+
+        const db = await database.getClient();
+
+        if (!database.migrations?.skip) {
+          await db.migrate.latest({
+            directory: MIGRATIONS_DIR,
+            tableName: DB_MIGRATIONS_TABLE,
+          });
+        }
+
+        // Attach the DB to each processor now that migrations have run.
+        for (const processor of processors) {
+          processor.setDatabase(db);
+        }
+
+        notifications.addProcessor(processors);
+
+        // Clean up old message timestamp records daily. These records are only
+        // needed for the short window between initial send and scope-based
+        // update (typically minutes), so a 24-hour retention is sufficient.
+        await scheduler.scheduleTask({
+          id: 'slack-message-timestamps-cleanup',
+          frequency: { hours: 24 },
+          timeout: { minutes: 5 },
+          initialDelay: { hours: 2 },
+          scope: 'global',
+          fn: async () => {
+            const deleted = await db('slack_message_timestamps')
+              .where(
+                'created_at',
+                '<=',
+                nowMinus(db, CLEANUP_RETENTION_SECONDS),
+              )
+              .delete();
+            logger.info('Cleaned up old Slack message timestamps', {
+              deleted,
+            });
+          },
+        });
       },
     });
   },
diff --git a/yarn.lock b/yarn.lock
index ade399ee0b..9af93c96f6 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -6245,6 +6245,7 @@ __metadata:
     "@slack/types": "npm:^2.14.0"
     "@slack/web-api": "npm:^7.5.0"
     dataloader: "npm:^2.0.0"
+    knex: "npm:^3.0.0"
     msw: "npm:^2.0.0"
     p-throttle: "npm:^4.1.1"
   languageName: unknown