diff --git a/app/javascript/dashboard/routes/dashboard/settings/inbox/Settings.vue b/app/javascript/dashboard/routes/dashboard/settings/inbox/Settings.vue
index 530106f0a..b91fc2414 100644
--- a/app/javascript/dashboard/routes/dashboard/settings/inbox/Settings.vue
+++ b/app/javascript/dashboard/routes/dashboard/settings/inbox/Settings.vue
@@ -175,7 +175,10 @@ export default {
     },
     canLocktoSingleConversation() {
       return (
-        this.isASmsInbox || this.isAWhatsAppChannel || this.isAFacebookInbox
+        this.isASmsInbox ||
+        this.isAWhatsAppChannel ||
+        this.isAFacebookInbox ||
+        this.isAPIInbox
       );
     },
     inboxNameLabel() {
diff --git a/spec/builders/conversation_builder_spec.rb b/spec/builders/conversation_builder_spec.rb
index 956aec966..c0c5f248b 100644
--- a/spec/builders/conversation_builder_spec.rb
+++ b/spec/builders/conversation_builder_spec.rb
@@ -3,39 +3,77 @@ require 'rails_helper'
 describe ConversationBuilder do
   let(:account) { create(:account) }
   let!(:sms_channel) { create(:channel_sms, account: account) }
+  let!(:api_channel) { create(:channel_api, account: account) }
   let!(:sms_inbox) { create(:inbox, channel: sms_channel, account: account) }
+  let!(:api_inbox) { create(:inbox, channel: api_channel, account: account) }
   let(:contact) { create(:contact, account: account) }
-  let(:contact_inbox) { create(:contact_inbox, contact: contact, inbox: sms_inbox) }
+  let(:contact_sms_inbox) { create(:contact_inbox, contact: contact, inbox: sms_inbox) }
+  let(:contact_api_inbox) { create(:contact_inbox, contact: contact, inbox: api_inbox) }
 
   describe '#perform' do
-    it 'creates conversation' do
+    it 'creates sms conversation' do
       conversation = described_class.new(
-        contact_inbox: contact_inbox,
+        contact_inbox: contact_sms_inbox,
         params: {}
       ).perform
 
-      expect(conversation.contact_inbox_id).to eq(contact_inbox.id)
+      expect(conversation.contact_inbox_id).to eq(contact_sms_inbox.id)
     end
 
-    context 'when lock_to_single_conversation is true for inbox' do
+    it 'creates api conversation' do
+      conversation = described_class.new(
+        contact_inbox: contact_api_inbox,
+        params: {}
+      ).perform
+
+      expect(conversation.contact_inbox_id).to eq(contact_api_inbox.id)
+    end
+
+    context 'when lock_to_single_conversation is true for sms inbox' do
       before do
         sms_inbox.update!(lock_to_single_conversation: true)
       end
 
-      it 'creates conversation when existing conversation is not present' do
+      it 'creates sms conversation when existing conversation is not present' do
         conversation = described_class.new(
-          contact_inbox: contact_inbox,
+          contact_inbox: contact_sms_inbox,
           params: {}
         ).perform
 
-        expect(conversation.contact_inbox_id).to eq(contact_inbox.id)
+        expect(conversation.contact_inbox_id).to eq(contact_sms_inbox.id)
       end
 
-      it 'returns last from existing conversations when existing conversation is not present' do
-        create(:conversation, contact_inbox: contact_inbox)
-        existing_conversation = create(:conversation, contact_inbox: contact_inbox)
+      it 'returns last from existing sms conversations when existing conversation is not present' do
+        create(:conversation, contact_inbox: contact_sms_inbox)
+        existing_conversation = create(:conversation, contact_inbox: contact_sms_inbox)
         conversation = described_class.new(
-          contact_inbox: contact_inbox,
+          contact_inbox: contact_sms_inbox,
+          params: {}
+        ).perform
+
+        expect(conversation.id).to eq(existing_conversation.id)
+      end
+    end
+
+    context 'when lock_to_single_conversation is true for api inbox' do
+      before do
+        api_inbox.update!(lock_to_single_conversation: true)
+      end
+
+      it 'creates conversation when existing api conversation is not present' do
+        conversation = described_class.new(
+          contact_inbox: contact_api_inbox,
+          params: {}
+        ).perform
+
+        expect(conversation.contact_inbox_id).to eq(contact_api_inbox.id)
+      end
+
+      it 'returns last from existing api conversations when existing conversation is not present' do
+        create(:conversation, contact_inbox: contact_api_inbox)
+        existing_conversation = create(:conversation, contact_inbox: contact_api_inbox)
+        conversation = described_class.new(
+          contact_inbox: contact_api_inbox,
           params: {}
         ).perform