diff --git a/packages/browser/package.json b/packages/browser/package.json
index fb26d84a7..8e0d6979f 100644
--- a/packages/browser/package.json
+++ b/packages/browser/package.json
@@ -52,7 +52,7 @@
     "@lukeed/uuid": "^2.0.0",
     "@segment/analytics.js-video-plugins": "^0.2.1",
     "@segment/facade": "^3.4.9",
-    "customerio-gist-web": "3.16.10",
+    "customerio-gist-web": "3.17.0",
     "dset": "^3.1.2",
     "js-cookie": "3.0.1",
     "node-fetch": "^2.6.7",
diff --git a/packages/browser/src/core/analytics/index.ts b/packages/browser/src/core/analytics/index.ts
index 6727a85bf..3c7759f97 100644
--- a/packages/browser/src/core/analytics/index.ts
+++ b/packages/browser/src/core/analytics/index.ts
@@ -131,6 +131,7 @@ export class Analytics
   integrations: Integrations
   options: InitOptions
   queue: EventQueue
+  inbox?: (...topics: string[]) => import('../../plugins/in-app-plugin').InboxAPI
 
   constructor(
     settings: AnalyticsSettings,
diff --git a/packages/browser/src/core/analytics/interfaces.ts b/packages/browser/src/core/analytics/interfaces.ts
index 0ec274784..bfcfc0fb8 100644
--- a/packages/browser/src/core/analytics/interfaces.ts
+++ b/packages/browser/src/core/analytics/interfaces.ts
@@ -12,6 +12,7 @@ import type { Context } from '../context'
 import type { CustomerioEvent } from '../events'
 import type { Group, User } from '../user'
 import type { LegacyIntegration } from '../../plugins/ajs-destination/types'
+import type { InboxAPI } from '../../plugins/in-app-plugin'
 import { CoreAnalytics } from '@customerio/cdp-analytics-core'
 
 // we can define a contract because:
@@ -88,6 +89,13 @@ export interface AnalyticsCore extends CoreAnalytics {
   deregister(...plugins: string[]): Promise<Context>
   user(): User
   readonly VERSION: string
+  /**
+   * Access inbox functionality provided by the Customer.io In-App Plugin.
+   * Only available when the In-App Plugin is loaded.
+   * @param topics - Optional topics to filter inbox messages
+   * @returns InboxAPI interface for managing inbox messages
+   */
+  inbox?(...topics: string[]): InboxAPI
 }
 
 /**
diff --git a/packages/browser/src/core/buffer/index.ts b/packages/browser/src/core/buffer/index.ts
index d7b42edb0..2843c2e54 100644
--- a/packages/browser/src/core/buffer/index.ts
+++ b/packages/browser/src/core/buffer/index.ts
@@ -241,6 +241,12 @@ export class AnalyticsBuffered
   register = this._createMethod('register')
   deregister = this._createMethod('deregister')
   user = this._createMethod('user')
+  inbox(...topics: string[]): import('../../plugins/in-app-plugin').InboxAPI {
+    if (this.instance?.inbox) {
+      return this.instance.inbox(...topics)
+    }
+    throw new Error('Customer.io In-App Plugin is not loaded yet. Ensure the plugin is initialized before calling inbox().')
+  }
   readonly VERSION = version
 
   private _createMethod<T extends PreInitMethodName>(methodName: T) {
diff --git a/packages/browser/src/plugins/in-app-plugin/inbox_messages.ts b/packages/browser/src/plugins/in-app-plugin/inbox_messages.ts
new file mode 100644
index 000000000..41694fef1
--- /dev/null
+++ b/packages/browser/src/plugins/in-app-plugin/inbox_messages.ts
@@ -0,0 +1,163 @@
+export interface GistInboxMessage {
+  messageType: string
+  expiry: string
+  priority: number
+  topics?: string[]
+  properties: { [key: string]: any }
+  queueId: string
+  userToken: string
+  deliveryId: string
+  sentAt: string
+  opened: boolean
+}
+
+export interface InboxMessage {
+  // Unique identifier for this messeage
+  readonly messageId: string
+
+  // If the message has been marked opened
+  readonly opened: boolean
+
+  // The properties payload of the message
+  readonly properties: { [key: string]: any }
+
+  // When the message was sent
+  readonly sentAt: string
+
+  /**
+   * Marks this message as opened
+   * @returns Promise that resolves when the message is marked as opened
+   */
+  markOpened(): Promise<void>
+
+  /**
+   * Marks this message as unopened
+   * @returns Promise that resolves when the message is marked as unopened
+   */
+  markUnopened(): Promise<void>
+
+  /**
+   * Marks this message as deleted
+   * @returns Promise that resolves when the message is deleted
+   */
+  markDeleted(): Promise<void>
+}
+
+export interface InboxAPI {
+  /**
+   * Returns the total number of messages
+   * @returns Promise that resolves to the total count of messages
+   */
+  total(): Promise<number>
+
+  /**
+   * Returns the count of unopened messages
+   * @returns Promise that resolves to the count of unopened messages
+   */
+  totalUnopened(): Promise<number>
+
+  /**
+   * Returns all inbox messages
+   * @returns Promise that resolves to an array of inbox messages
+   */
+  messages(): Promise<InboxMessage[]>
+
+  /**
+   * Subscribe to inbox message updates
+   * @param callback - Function called with array of InboxMessage objects when the message list changes.
+   * @returns Unsubscribe function to remove the listener
+   */
+  onUpdates(callback: (messages: InboxMessage[]) => void): () => void
+}
+
+function createInboxMessage(
+  gist: any,
+  gistMessage: GistInboxMessage
+): InboxMessage {
+  return {
+    sentAt: gistMessage.sentAt,
+    messageId: gistMessage.queueId,
+    opened: gistMessage?.opened === true,
+    properties: gistMessage.properties,
+    markOpened: async () => {
+      await gist.updateInboxMessageOpenState(gistMessage.queueId, true)
+    },
+    markUnopened: async () => {
+      await gist.updateInboxMessageOpenState(gistMessage.queueId, false)
+    },
+    markDeleted: async () => {
+      await gist.removeInboxMessage(gistMessage.queueId)
+    },
+  }
+}
+
+async function getFilteredMessages(
+  gist: any,
+  topics: string[],
+  messages: GistInboxMessage[] | null
+): Promise<GistInboxMessage[]> {
+  let allMessages = messages
+  if (!allMessages || !Array.isArray(allMessages)) {
+    allMessages = (await gist.getInboxMessages()) as GistInboxMessage[]
+  }
+
+  if (!allMessages || !Array.isArray(allMessages)) {
+    return []
+  }
+
+  if (topics.length === 0) {
+    return allMessages
+  }
+
+  return allMessages.filter((message) => {
+    const messageTopics = message.topics
+    if (!messageTopics || messageTopics.length === 0) {
+      return false
+    }
+    return messageTopics.some((messageTopic) => topics.includes(messageTopic))
+  })
+}
+
+export function createInboxAPI(gist: any, topics: string[]): InboxAPI {
+  return {
+    total: async () => {
+      const messages = await getFilteredMessages(gist, topics, null)
+      return messages.length
+    },
+    totalUnopened: async () => {
+      const messages = await getFilteredMessages(gist, topics, null)
+      return messages.filter((message) => {
+        return message?.opened !== true
+      }).length
+    },
+    messages: async (): Promise<InboxMessage[]> => {
+      const messages = await getFilteredMessages(gist, topics, null)
+      return messages.map((msg) => createInboxMessage(gist, msg))
+    },
+    onUpdates: (callback: (messages: InboxMessage[]) => void): (() => void) => {
+      const handler = async (gistMessages: GistInboxMessage[]) => {
+        try {
+          const filteredMessages = await getFilteredMessages(
+            gist,
+            topics,
+            gistMessages
+          )
+          const inboxMessages = filteredMessages.map((msg) =>
+            createInboxMessage(gist, msg)
+          )
+
+          callback(inboxMessages)
+        } catch (error) {
+          console.error('Error processing inbox updates:', error)
+        }
+      }
+
+      gist.events.on('messageInboxUpdated', handler)
+
+      // Return unsubscribe function
+      return () => {
+        gist.events.off('messageInboxUpdated', handler)
+      }
+    },
+  }
+}
diff --git a/packages/browser/src/plugins/in-app-plugin/index.ts b/packages/browser/src/plugins/in-app-plugin/index.ts
index 81887385f..b799d656c 100644
--- a/packages/browser/src/plugins/in-app-plugin/index.ts
+++ b/packages/browser/src/plugins/in-app-plugin/index.ts
@@ -11,8 +11,11 @@ import {
   ContentType,
 } from './events'
 import Gist from 'customerio-gist-web'
+import type { InboxAPI, InboxMessage, GistInboxMessage } from './inbox_messages'
+import { createInboxAPI } from './inbox_messages'
 
 export { InAppEvents }
+export type { InboxAPI, InboxMessage }
 
 export type InAppPluginSettings = {
   siteId: string | undefined
@@ -96,6 +99,12 @@ export function InAppPlugin(settings: InAppPluginSettings): Plugin {
       }
     })
 
+    Gist.events.on('inboxMessageAction', (params: any) => {
+      if (params?.message && params?.action !== '') {
+        _handleInboxMessageAction(_analytics, params.message, params.action)
+      }
+    })
+
     Gist.events.on('messageAction', (params: any) => {
       const deliveryId: string = params?.message?.properties?.gist?.campaignId
       if (settings.events) {
@@ -214,6 +223,14 @@ export function InAppPlugin(settings: InAppPluginSettings): Plugin {
 
       await syncUserToken(ctx)
       attachListeners()
+      ;(instance as any).inbox = (...topics: string[]): InboxAPI => {
+        if (!_pluginLoaded) {
+          throw new Error(
+            'Customer.io In-App Plugin is not loaded yet. Ensure the plugin is initialized before calling inbox().'
+          )
+        }
+        return createInboxAPI(Gist, topics)
+      }
 
       _pluginLoaded = true
 
@@ -236,6 +253,20 @@ export function InAppPlugin(settings: InAppPluginSettings): Plugin {
   return customerio
 }
 
+function _handleInboxMessageAction(
+  analyticsInstance: Analytics,
+  message: GistInboxMessage,
+  action: string
+) {
+  const deliveryId = message?.deliveryId
+  if (action === 'opened' && typeof deliveryId !== 'undefined' && deliveryId !== '') {
+    void analyticsInstance.track(JourneysEvents.Metric, {
+      deliveryId: message.deliveryId,
+      metric: JourneysEvents.Opened,
+    })
+  }
+}
+
 function _error(msg: string) {
   console.error(`[Customer.io In-App Plugin] ${msg}`)
 }
diff --git a/yarn.lock b/yarn.lock
index 7a300de2a..6b7c43921 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -777,7 +777,7 @@ __metadata:
     aws-sdk: ^2.814.0
     circular-dependency-plugin: ^5.2.2
     compression-webpack-plugin: ^8.0.1
-    customerio-gist-web: 3.16.10
+    customerio-gist-web: 3.17.0
     dset: ^3.1.2
     execa: ^4.1.0
     flat: ^5.0.2
@@ -5497,12 +5497,12 @@ __metadata:
   languageName: node
   linkType: hard
 
-"customerio-gist-web@npm:3.16.10":
-  version: 3.16.10
-  resolution: "customerio-gist-web@npm:3.16.10"
+"customerio-gist-web@npm:3.17.0":
+  version: 3.17.0
+  resolution: "customerio-gist-web@npm:3.17.0"
   dependencies:
     uuid: ^8.3.2
-  checksum: 7d6a3c1e4ea0c945c66ea9dee4bdc927715b539380820cc65b641660285025233d28f49789db47a2e90adda70720219bbad7e9acad29b408eaf0a502f172be56
+  checksum: 981d3aaa93fe2048e70cc4c231451cea85204fb8e17adf079de8e5dd0e0e98bd3bc62ebb656bcf45111781beee6b6e3a5d807ae09f6315c2c52c5fc8dd29815c
   languageName: node
   linkType: hard