diff --git a/app/javascript/dashboard/api/companies.js b/app/javascript/dashboard/api/companies.js
index b98a59983..a45b21d68 100644
--- a/app/javascript/dashboard/api/companies.js
+++ b/app/javascript/dashboard/api/companies.js
@@ -28,6 +28,14 @@ class CompanyAPI extends ApiClient {
     return axios.get(`${this.url}/${id}/contacts?${buildParams({ page })}`);
   }
 
+  listNotes(id) {
+    return axios.get(`${this.url}/${id}/notes`);
+  }
+
+  listConversations(id) {
+    return axios.get(`${this.url}/${id}/conversations`);
+  }
+
   searchContacts(id, query = '', page = 1) {
     const requestURL = `${this.url}/${id}/contacts/search?${buildParams({ q: query, page })}`;
     return axios.get(requestURL);
diff --git a/app/javascript/dashboard/components-next/Companies/CompaniesDetailsLayout.vue b/app/javascript/dashboard/components-next/Companies/CompaniesDetailsLayout.vue
index 7736ccffd..14b5e62d9 100644
--- a/app/javascript/dashboard/components-next/Companies/CompaniesDetailsLayout.vue
+++ b/app/javascript/dashboard/components-next/Companies/CompaniesDetailsLayout.vue
@@ -56,9 +56,14 @@ const closeMobileSidebar = () => {
 
     <div
       v-if="slots.sidebar"
-      class="hidden lg:block overflow-y-auto justify-end min-w-52 w-full py-6 max-w-md border-l border-n-weak bg-n-solid-2"
+      class="hidden lg:flex flex-col min-w-52 w-full max-w-md border-l border-n-weak bg-n-solid-2"
     >
-      <slot name="sidebar" />
+      <div class="shrink-0">
+        <slot name="sidebarHeader" />
+      </div>
+      <div class="flex-1 overflow-y-auto pb-6 pt-3">
+        <slot name="sidebar" />
+      </div>
     </div>
 
     <div
@@ -105,9 +110,14 @@ const closeMobileSidebar = () => {
         <div
           v-if="isSidebarOpen"
           id="details-sidebar-content"
-          class="order-2 w-[85%] sm:w-[50%] bg-n-solid-2 ltr:border-l rtl:border-r border-n-weak overflow-y-auto py-6 shadow-lg"
+          class="order-2 w-[85%] sm:w-[50%] flex flex-col bg-n-solid-2 ltr:border-l rtl:border-r border-n-weak shadow-lg"
         >
-          <slot name="sidebar" />
+          <div class="shrink-0">
+            <slot name="sidebarHeader" />
+          </div>
+          <div class="flex-1 overflow-y-auto pb-6 pt-3">
+            <slot name="sidebar" />
+          </div>
         </div>
       </Transition>
     </div>
diff --git a/app/javascript/dashboard/components-next/Companies/CompanyDetail/CompanyContactsSidebar.vue b/app/javascript/dashboard/components-next/Companies/CompanyDetail/CompanyContactsSidebar.vue
index 7e0d162dc..ce2a68da1 100644
--- a/app/javascript/dashboard/components-next/Companies/CompanyDetail/CompanyContactsSidebar.vue
+++ b/app/javascript/dashboard/components-next/Companies/CompanyDetail/CompanyContactsSidebar.vue
@@ -169,7 +169,7 @@ const handleContactSelect = contactId => {
 </script>
 
 <template>
-  <div class="flex flex-col gap-6 px-6 pb-8 pt-1">
+  <div class="flex flex-col gap-6 px-6 pb-8">
     <div v-if="!selectedContact" class="flex flex-col gap-4">
       <div class="flex flex-col gap-2">
         <label class="text-base text-n-slate-12">
@@ -288,7 +288,7 @@ const handleContactSelect = contactId => {
 
       <div
         v-else-if="!hasContacts"
-        class="py-8 text-sm text-center rounded-xl border border-dashed border-n-weak text-n-slate-11"
+        class="py-8 px-4 text-sm text-center rounded-xl border border-dashed border-n-strong text-n-slate-11"
       >
         {{ t('COMPANIES.DETAIL.CONTACTS.EMPTY') }}
       </div>
@@ -346,7 +346,7 @@ const handleContactSelect = contactId => {
         :current-page="currentPage"
         :total-items="totalContacts"
         :items-per-page="15"
-        class="!px-0 before:hidden"
+        class="!px-0 before:hidden bg-transparent"
         @update:current-page="emit('update:currentPage', $event)"
       />
     </div>
diff --git a/app/javascript/dashboard/components-next/Companies/CompanyDetail/CompanyHistorySidebar.vue b/app/javascript/dashboard/components-next/Companies/CompanyDetail/CompanyHistorySidebar.vue
new file mode 100644
index 000000000..c82ed71fb
--- /dev/null
+++ b/app/javascript/dashboard/components-next/Companies/CompanyDetail/CompanyHistorySidebar.vue
@@ -0,0 +1,67 @@
+<script setup>
+import { computed } from 'vue';
+import { useI18n } from 'vue-i18n';
+import { useMapGetter } from 'dashboard/composables/store';
+
+import ConversationCard from 'dashboard/components-next/Conversation/ConversationCard/ConversationCard.vue';
+import Spinner from 'dashboard/components-next/spinner/Spinner.vue';
+
+defineProps({
+  conversations: {
+    type: Array,
+    default: () => [],
+  },
+  isLoading: {
+    type: Boolean,
+    default: false,
+  },
+});
+
+const { t } = useI18n();
+const contactsById = useMapGetter('contacts/getContactById');
+const stateInbox = useMapGetter('inboxes/getInboxById');
+const accountLabels = useMapGetter('labels/getLabels');
+
+const accountLabelsValue = computed(() => accountLabels.value);
+const conversationContact = conversation => {
+  const sender = conversation.meta?.sender || {};
+  const contact = contactsById.value(sender.id);
+  return contact.id ? contact : sender;
+};
+const conversationInbox = conversation =>
+  stateInbox.value(conversation.inboxId) || {
+    name: '',
+    channelType: conversation.meta?.channel,
+  };
+</script>
+
+<template>
+  <div
+    v-if="isLoading"
+    class="flex items-center justify-center py-10 text-n-slate-11"
+  >
+    <Spinner />
+  </div>
+
+  <div
+    v-else-if="conversations.length > 0"
+    class="px-6 divide-y divide-n-strong [&>*:hover]:!border-y-transparent [&>*:hover+*]:!border-t-transparent"
+  >
+    <ConversationCard
+      v-for="conversation in conversations"
+      :key="conversation.id"
+      :conversation="conversation"
+      :contact="conversationContact(conversation)"
+      :state-inbox="conversationInbox(conversation)"
+      :account-labels="accountLabelsValue"
+      class="rounded-none hover:rounded-xl hover:bg-n-alpha-1 dark:hover:bg-n-alpha-3"
+    />
+  </div>
+
+  <p
+    v-else
+    class="py-8 px-4 mx-6 text-sm text-center rounded-xl border border-dashed border-n-strong text-n-slate-11"
+  >
+    {{ t('COMPANIES.DETAIL.HISTORY.EMPTY') }}
+  </p>
+</template>
diff --git a/app/javascript/dashboard/components-next/Companies/CompanyDetail/CompanyNotesSidebar.vue b/app/javascript/dashboard/components-next/Companies/CompanyDetail/CompanyNotesSidebar.vue
new file mode 100644
index 000000000..234e0cd12
--- /dev/null
+++ b/app/javascript/dashboard/components-next/Companies/CompanyDetail/CompanyNotesSidebar.vue
@@ -0,0 +1,114 @@
+<script setup>
+import { computed } from 'vue';
+import { useI18n } from 'vue-i18n';
+import { useRoute, useRouter } from 'vue-router';
+import { useMapGetter } from 'dashboard/composables/store';
+import { dynamicTime } from 'shared/helpers/timeHelper';
+import { useMessageFormatter } from 'shared/composables/useMessageFormatter';
+
+import Avatar from 'dashboard/components-next/avatar/Avatar.vue';
+import Spinner from 'dashboard/components-next/spinner/Spinner.vue';
+
+const props = defineProps({
+  notes: {
+    type: Array,
+    default: () => [],
+  },
+  isLoading: {
+    type: Boolean,
+    default: false,
+  },
+});
+
+const route = useRoute();
+const router = useRouter();
+const { t } = useI18n();
+const { formatMessage } = useMessageFormatter();
+const currentUser = useMapGetter('getCurrentUser');
+
+const hasNotes = computed(() => props.notes.length > 0);
+
+const contactName = contact =>
+  contact?.name || t('COMPANIES.DETAIL.CONTACTS.UNNAMED_CONTACT');
+
+const getWrittenBy = note => {
+  const isCurrentUser = note?.user?.id === currentUser.value.id;
+  return isCurrentUser
+    ? t('CONTACTS_LAYOUT.SIDEBAR.NOTES.YOU')
+    : note?.user?.name || 'Bot';
+};
+
+const openContact = contactId => {
+  router.push({
+    name: 'contacts_edit',
+    params: {
+      accountId: route.params.accountId,
+      contactId,
+    },
+  });
+};
+</script>
+
+<template>
+  <div v-if="hasNotes" class="flex flex-col px-6">
+    <div class="flex flex-col divide-y divide-n-strong">
+      <div
+        v-for="note in notes"
+        :key="note.id"
+        class="flex flex-col gap-2 py-4 group/note"
+      >
+        <div class="flex items-center gap-1.5 min-w-0">
+          <Avatar
+            :name="contactName(note.contact)"
+            :src="note.contact?.thumbnail"
+            :size="16"
+            rounded-full
+            hide-offline-status
+          />
+          <div
+            class="flex items-center justify-between min-w-0 gap-1 w-full text-sm text-n-slate-11"
+          >
+            <button
+              type="button"
+              class="min-w-0 font-medium truncate text-start text-n-slate-12 hover:text-n-blue-11 p-0"
+              @click="openContact(note.contact.id)"
+            >
+              {{ contactName(note.contact) }}
+            </button>
+            <div class="min-w-0 truncate">
+              <span
+                class="inline-flex items-center gap-1 text-sm text-n-slate-10"
+              >
+                <span class="font-medium text-n-slate-11">
+                  {{ getWrittenBy(note) }}
+                </span>
+                {{ t('CONTACTS_LAYOUT.SIDEBAR.NOTES.WROTE') }}
+                <span class="font-medium text-n-slate-11">
+                  {{ dynamicTime(note.createdAt) }}
+                </span>
+              </span>
+            </div>
+          </div>
+        </div>
+        <p
+          v-dompurify-html="formatMessage(note.content || '')"
+          class="mb-0 prose-sm prose-p:text-sm prose-p:leading-relaxed prose-p:mb-1 prose-p:mt-0 prose-ul:mb-1 prose-ul:mt-0 text-n-slate-12"
+        />
+      </div>
+    </div>
+  </div>
+
+  <div
+    v-else-if="isLoading"
+    class="flex items-center justify-center py-10 text-n-slate-11"
+  >
+    <Spinner />
+  </div>
+
+  <p
+    v-else
+    class="py-8 mx-6 px-4 text-sm text-center rounded-xl border border-dashed border-n-strong text-n-slate-11"
+  >
+    {{ t('COMPANIES.DETAIL.NOTES.EMPTY') }}
+  </p>
+</template>
diff --git a/app/javascript/dashboard/i18n/locale/en/companies.json b/app/javascript/dashboard/i18n/locale/en/companies.json
index 1fe8bc169..534205038 100644
--- a/app/javascript/dashboard/i18n/locale/en/companies.json
+++ b/app/javascript/dashboard/i18n/locale/en/companies.json
@@ -44,9 +44,17 @@
       "SIDEBAR": {
         "TABS": {
           "ATTRIBUTES": "Attributes",
-          "CONTACTS": "Contacts"
+          "CONTACTS": "Contacts",
+          "HISTORY": "History",
+          "NOTES": "Notes"
         }
       },
+      "HISTORY": {
+        "EMPTY": "No conversations found for this company's contacts yet."
+      },
+      "NOTES": {
+        "EMPTY": "No notes found for this company's contacts yet."
+      },
       "ATTRIBUTES": {
         "SEARCH_PLACEHOLDER": "Search attributes...",
         "EMPTY_STATE": "There are no company custom attributes configured yet.",
diff --git a/app/javascript/dashboard/routes/dashboard/companies/pages/CompanyDetailView.vue b/app/javascript/dashboard/routes/dashboard/companies/pages/CompanyDetailView.vue
index 313df49d3..86627f952 100644
--- a/app/javascript/dashboard/routes/dashboard/companies/pages/CompanyDetailView.vue
+++ b/app/javascript/dashboard/routes/dashboard/companies/pages/CompanyDetailView.vue
@@ -8,7 +8,10 @@ import Policy from 'dashboard/components/policy.vue';
 import Button from 'dashboard/components-next/button/Button.vue';
 import CompaniesDetailsLayout from 'dashboard/components-next/Companies/CompaniesDetailsLayout.vue';
 import Spinner from 'dashboard/components-next/spinner/Spinner.vue';
+import TabBar from 'dashboard/components-next/tabbar/TabBar.vue';
 import CompanyContactsSidebar from 'dashboard/components-next/Companies/CompanyDetail/CompanyContactsSidebar.vue';
+import CompanyHistorySidebar from 'dashboard/components-next/Companies/CompanyDetail/CompanyHistorySidebar.vue';
+import CompanyNotesSidebar from 'dashboard/components-next/Companies/CompanyDetail/CompanyNotesSidebar.vue';
 import CompanyProfileCard from 'dashboard/components-next/Companies/CompanyDetail/CompanyProfileCard.vue';
 import ConfirmCompanyDeleteDialog from 'dashboard/components-next/Companies/CompanyDetail/ConfirmCompanyDeleteDialog.vue';
 import { useCompaniesStore } from 'dashboard/stores/companies';
@@ -20,11 +23,16 @@ const { t } = useI18n();
 
 const confirmDeleteDialogRef = ref(null);
 const selectedCandidate = ref(null);
+const activeSidebarTab = ref('history');
 
 const companyId = computed(() => Number(route.params.companyId));
 const company = computed(() => companiesStore.getRecord(companyId.value));
 const companyContacts = computed(() => companiesStore.companyContacts);
 const companyContactsMeta = computed(() => companiesStore.companyContactsMeta);
+const companyConversations = computed(
+  () => companiesStore.companyConversations || []
+);
+const companyNotes = computed(() => companiesStore.companyNotes || []);
 const contactSearchResults = computed(
   () => companiesStore.contactSearchResults
 );
@@ -32,6 +40,10 @@ const uiFlags = computed(() => companiesStore.getUIFlags);
 
 const isFetchingCompany = computed(() => uiFlags.value.fetchingItem);
 const isFetchingContacts = computed(() => uiFlags.value.fetchingContacts);
+const isFetchingConversations = computed(
+  () => uiFlags.value.fetchingConversations
+);
+const isFetchingNotes = computed(() => uiFlags.value.fetchingNotes);
 const isSearchingContacts = computed(() => uiFlags.value.searchingContacts);
 const isManagingContacts = computed(
   () => uiFlags.value.creatingContact || uiFlags.value.removingContact
@@ -50,6 +62,27 @@ const breadcrumbItems = computed(() => [
     : []),
 ]);
 
+const SIDEBAR_TABS_OPTIONS = [
+  { key: 'HISTORY', value: 'history' },
+  { key: 'NOTES', value: 'notes' },
+  { key: 'CONTACTS', value: 'contacts' },
+];
+
+const sidebarTabs = computed(() =>
+  SIDEBAR_TABS_OPTIONS.map(tab => ({
+    label: {
+      notes: t('COMPANIES.DETAIL.SIDEBAR.TABS.NOTES'),
+      history: t('COMPANIES.DETAIL.SIDEBAR.TABS.HISTORY'),
+      contacts: `${t('COMPANIES.DETAIL.SIDEBAR.TABS.CONTACTS')} (${Number(companyContactsMeta.value.totalCount || 0)})`,
+    }[tab.value],
+    value: tab.value,
+  }))
+);
+
+const activeSidebarTabIndex = computed(() =>
+  SIDEBAR_TABS_OPTIONS.findIndex(tab => tab.value === activeSidebarTab.value)
+);
+
 const goToCompaniesIndex = () => {
   router.push({
     name: 'companies_dashboard_index',
@@ -79,6 +112,19 @@ const clearSelectedCandidate = () => {
   selectedCandidate.value = null;
 };
 
+const loadSidebarTab = tab => {
+  if (!companyId.value) return;
+  if (tab === 'notes') companiesStore.getCompanyNotes(companyId.value);
+  if (tab === 'history') {
+    companiesStore.getCompanyConversations(companyId.value);
+  }
+};
+
+const handleSidebarTabChange = tab => {
+  activeSidebarTab.value = tab.value;
+  loadSidebarTab(tab.value);
+};
+
 const handleContactSearch = async query => {
   await companiesStore.searchCompanyContactCandidates({
     companyId: companyId.value,
@@ -143,10 +189,12 @@ watch(
   async id => {
     companiesStore.resetCompanyDetailState();
     clearSelectedCandidate();
+    activeSidebarTab.value = 'history';
     if (!id) return;
     await Promise.allSettled([
       companiesStore.show(id),
       companiesStore.getCompanyContacts(id),
+      companiesStore.getCompanyConversations(id),
     ]);
   },
   { immediate: true }
@@ -207,8 +255,29 @@ onBeforeUnmount(() => {
       </Policy>
     </div>
 
+    <template #sidebarHeader>
+      <div class="px-6 pt-6 pb-3">
+        <TabBar
+          :tabs="sidebarTabs"
+          :initial-active-tab="activeSidebarTabIndex"
+          class="w-full [&>button]:w-full bg-n-alpha-black2"
+          @tab-changed="handleSidebarTabChange"
+        />
+      </div>
+    </template>
     <template v-if="hasCompany" #sidebar>
+      <CompanyNotesSidebar
+        v-if="activeSidebarTab === 'notes'"
+        :notes="companyNotes"
+        :is-loading="isFetchingNotes"
+      />
+      <CompanyHistorySidebar
+        v-if="activeSidebarTab === 'history'"
+        :conversations="companyConversations"
+        :is-loading="isFetchingConversations"
+      />
       <CompanyContactsSidebar
+        v-if="activeSidebarTab === 'contacts'"
         :company="company"
         :contacts="companyContacts"
         :meta="companyContactsMeta"
diff --git a/app/javascript/dashboard/store/storeFactory.js b/app/javascript/dashboard/store/storeFactory.js
index a623b4785..9a6d7ec01 100644
--- a/app/javascript/dashboard/store/storeFactory.js
+++ b/app/javascript/dashboard/store/storeFactory.js
@@ -134,10 +134,13 @@ export const createVuexStore = options => {
  * @returns {Function} Pinia store composable
  */
 export const createPiniaStore = options => {
-  const { name, API, actions, getters } = options;
+  const { name, API, actions, getters, state } = options;
 
   return defineStore(name.toLowerCase(), {
-    state: createInitialState,
+    state: () => ({
+      ...createInitialState(),
+      ...(state ? state() : {}),
+    }),
 
     getters: {
       ...createGetters(),
diff --git a/app/javascript/dashboard/stores/companies.js b/app/javascript/dashboard/stores/companies.js
index 1a0d53b41..818e4829f 100644
--- a/app/javascript/dashboard/stores/companies.js
+++ b/app/javascript/dashboard/stores/companies.js
@@ -13,6 +13,8 @@ const createInitialUIFlags = () => ({
   deletingAvatar: false,
   deletingCustomAttributes: false,
   fetchingContacts: false,
+  fetchingConversations: false,
+  fetchingNotes: false,
   searchingContacts: false,
   creatingContact: false,
   removingContact: false,
@@ -67,6 +69,16 @@ export const useCompaniesStore = createStore({
   name: 'companies',
   type: 'pinia',
   API: CompanyAPI,
+  state: () => ({
+    activeCompanyId: null,
+    companyContacts: [],
+    companyContactsMeta: {},
+    companyConversations: [],
+    companyNotes: [],
+    contactSearchResults: [],
+    contactSearchMeta: {},
+    activeContactSearchQuery: '',
+  }),
 
   getters: {
     getCompaniesList: state => state.records,
@@ -270,6 +282,74 @@ export const useCompaniesStore = createStore({
       }
     },
 
+    async getCompanyNotes(companyId) {
+      this.setUIFlag({ fetchingNotes: true });
+      this.ensureActiveCompanyContext(companyId);
+      const activeCompanyId = Number(companyId);
+      const requestToken = (this.companyNotesRequestToken || 0) + 1;
+      this.companyNotesRequestToken = requestToken;
+
+      try {
+        const {
+          data: { payload },
+        } = await CompanyAPI.listNotes(companyId);
+        const notes = camelcaseKeys(payload || [], { deep: true });
+
+        if (
+          this.companyNotesRequestToken !== requestToken ||
+          this.activeCompanyId !== activeCompanyId
+        ) {
+          return notes;
+        }
+
+        this.companyNotes = notes;
+        return notes;
+      } catch (error) {
+        return throwErrorMessage(error);
+      } finally {
+        if (
+          this.companyNotesRequestToken === requestToken &&
+          this.activeCompanyId === activeCompanyId
+        ) {
+          this.setUIFlag({ fetchingNotes: false });
+        }
+      }
+    },
+
+    async getCompanyConversations(companyId) {
+      this.setUIFlag({ fetchingConversations: true });
+      this.ensureActiveCompanyContext(companyId);
+      const activeCompanyId = Number(companyId);
+      const requestToken = (this.companyConversationsRequestToken || 0) + 1;
+      this.companyConversationsRequestToken = requestToken;
+
+      try {
+        const {
+          data: { payload },
+        } = await CompanyAPI.listConversations(companyId);
+        const conversations = camelcaseKeys(payload || [], { deep: true });
+
+        if (
+          this.companyConversationsRequestToken !== requestToken ||
+          this.activeCompanyId !== activeCompanyId
+        ) {
+          return conversations;
+        }
+
+        this.companyConversations = conversations;
+        return conversations;
+      } catch (error) {
+        return throwErrorMessage(error);
+      } finally {
+        if (
+          this.companyConversationsRequestToken === requestToken &&
+          this.activeCompanyId === activeCompanyId
+        ) {
+          this.setUIFlag({ fetchingConversations: false });
+        }
+      }
+    },
+
     async searchCompanyContactCandidates({ companyId, search, page = 1 }) {
       const query = search?.trim() || '';
       if (!query) {
@@ -379,10 +459,15 @@ export const useCompaniesStore = createStore({
         (this.companyDetailRequestToken || 0) + 1;
       this.companyContactsRequestToken =
         (this.companyContactsRequestToken || 0) + 1;
+      this.companyConversationsRequestToken =
+        (this.companyConversationsRequestToken || 0) + 1;
+      this.companyNotesRequestToken = (this.companyNotesRequestToken || 0) + 1;
       this.contactSearchRequestToken =
         (this.contactSearchRequestToken || 0) + 1;
       this.companyContacts = [];
       this.companyContactsMeta = {};
+      this.companyConversations = [];
+      this.companyNotes = [];
       this.contactSearchResults = [];
       this.contactSearchMeta = {};
       this.activeContactSearchQuery = '';
diff --git a/config/routes.rb b/config/routes.rb
index fde0f64dd..ba6a33940 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -187,6 +187,8 @@ Rails.application.routes.draw do
                   get :search
                 end
               end
+              resources :conversations, only: [:index]
+              resources :notes, only: [:index]
             end
           end
           resources :contacts, only: [:index, :show, :update, :create, :destroy] do
diff --git a/enterprise/app/controllers/api/v1/accounts/companies/base_controller.rb b/enterprise/app/controllers/api/v1/accounts/companies/base_controller.rb
new file mode 100644
index 000000000..197a6425c
--- /dev/null
+++ b/enterprise/app/controllers/api/v1/accounts/companies/base_controller.rb
@@ -0,0 +1,24 @@
+class Api::V1::Accounts::Companies::BaseController < Api::V1::Accounts::EnterpriseAccountsController
+  before_action :ensure_companies_enabled!
+  before_action :fetch_company
+
+  private
+
+  def ensure_companies_enabled!
+    return if Current.account.feature_enabled?('companies')
+
+    render json: { error: 'Companies are not enabled for this account' }, status: :forbidden
+  end
+
+  def fetch_company
+    @company = Current.account.companies.find(params[:company_id])
+  end
+
+  def authorize_company_read!
+    authorize(@company, :show?)
+  end
+
+  def authorize_company_update!
+    authorize(@company, :update?)
+  end
+end
diff --git a/enterprise/app/controllers/api/v1/accounts/companies/contacts_controller.rb b/enterprise/app/controllers/api/v1/accounts/companies/contacts_controller.rb
index a67ad907b..07c7b8a99 100644
--- a/enterprise/app/controllers/api/v1/accounts/companies/contacts_controller.rb
+++ b/enterprise/app/controllers/api/v1/accounts/companies/contacts_controller.rb
@@ -1,4 +1,4 @@
-class Api::V1::Accounts::Companies::ContactsController < Api::V1::Accounts::EnterpriseAccountsController
+class Api::V1::Accounts::Companies::ContactsController < Api::V1::Accounts::Companies::BaseController
   RESULTS_PER_PAGE = 15
   CONTACT_SEARCH_QUERY = [
     'contacts.name ILIKE :search',
@@ -7,8 +7,6 @@ class Api::V1::Accounts::Companies::ContactsController < Api::V1::Accounts::Ente
     'contacts.identifier ILIKE :search'
   ].join(' OR ')
 
-  before_action :ensure_companies_enabled!
-  before_action :fetch_company
   before_action :authorize_company_read!, only: [:index, :search]
   before_action :authorize_company_update!, only: [:create, :destroy]
   before_action :set_current_page, only: [:index, :search]
@@ -45,10 +43,6 @@ class Api::V1::Accounts::Companies::ContactsController < Api::V1::Accounts::Ente
     @current_page = params[:page] || 1
   end
 
-  def fetch_company
-    @company = Current.account.companies.find(params[:company_id])
-  end
-
   def fetch_contact
     @contact = @company.contacts.find(params[:id])
   end
@@ -70,18 +64,4 @@ class Api::V1::Accounts::Companies::ContactsController < Api::V1::Accounts::Ente
   def membership_service
     @membership_service ||= Companies::ContactMembershipService.new(company: @company)
   end
-
-  def ensure_companies_enabled!
-    return if Current.account.feature_enabled?('companies')
-
-    render json: { error: 'Companies are not enabled for this account' }, status: :forbidden
-  end
-
-  def authorize_company_read!
-    authorize(@company, :show?)
-  end
-
-  def authorize_company_update!
-    authorize(@company, :update?)
-  end
 end
diff --git a/enterprise/app/controllers/api/v1/accounts/companies/conversations_controller.rb b/enterprise/app/controllers/api/v1/accounts/companies/conversations_controller.rb
new file mode 100644
index 000000000..e6944674e
--- /dev/null
+++ b/enterprise/app/controllers/api/v1/accounts/companies/conversations_controller.rb
@@ -0,0 +1,15 @@
+class Api::V1::Accounts::Companies::ConversationsController < Api::V1::Accounts::Companies::BaseController
+  before_action :authorize_company_read!
+
+  def index
+    conversations = Current.account.conversations.includes(
+      :assignee, :contact, :inbox, :taggings
+    ).where(contact_id: @company.contacts.select(:id))
+
+    @conversations = Conversations::PermissionFilterService.new(
+      conversations,
+      Current.user,
+      Current.account
+    ).perform.order(last_activity_at: :desc).limit(20)
+  end
+end
diff --git a/enterprise/app/controllers/api/v1/accounts/companies/notes_controller.rb b/enterprise/app/controllers/api/v1/accounts/companies/notes_controller.rb
new file mode 100644
index 000000000..85c3df034
--- /dev/null
+++ b/enterprise/app/controllers/api/v1/accounts/companies/notes_controller.rb
@@ -0,0 +1,11 @@
+class Api::V1::Accounts::Companies::NotesController < Api::V1::Accounts::Companies::BaseController
+  before_action :authorize_company_read!
+
+  def index
+    @notes = Current.account.notes
+                    .where(contact_id: @company.contacts.select(:id))
+                    .latest
+                    .includes(:contact, :user)
+                    .limit(20)
+  end
+end
diff --git a/enterprise/app/views/api/v1/accounts/companies/conversations/index.json.jbuilder b/enterprise/app/views/api/v1/accounts/companies/conversations/index.json.jbuilder
new file mode 100644
index 000000000..c81e4bdd0
--- /dev/null
+++ b/enterprise/app/views/api/v1/accounts/companies/conversations/index.json.jbuilder
@@ -0,0 +1,5 @@
+json.payload do
+  json.array! @conversations do |conversation|
+    json.partial! 'api/v1/conversations/partials/conversation', formats: [:json], conversation: conversation
+  end
+end
diff --git a/enterprise/app/views/api/v1/accounts/companies/notes/index.json.jbuilder b/enterprise/app/views/api/v1/accounts/companies/notes/index.json.jbuilder
new file mode 100644
index 000000000..053ebcd97
--- /dev/null
+++ b/enterprise/app/views/api/v1/accounts/companies/notes/index.json.jbuilder
@@ -0,0 +1,8 @@
+json.payload do
+  json.array! @notes do |note|
+    json.partial! 'api/v1/models/note', formats: [:json], resource: note
+    json.contact do
+      json.partial! 'api/v1/models/contact', formats: [:json], resource: note.contact
+    end
+  end
+end