diff --git a/app/services/emoji_react_service.rb b/app/services/emoji_react_service.rb
index c3135bdff2d8c3..a827ddc93e031d 100644
--- a/app/services/emoji_react_service.rb
+++ b/app/services/emoji_react_service.rb
@@ -23,7 +23,10 @@ def call(account, status, name)
       raise Mastodon::ValidationError, I18n.t('reactions.errors.duplication') unless emoji_reaction.nil?
 
       shortcode, domain = name.split('@')
+      domain = nil if TagManager.instance.local_domain?(domain)
       custom_emoji = CustomEmoji.find_by(shortcode: shortcode, domain: domain)
+      return if domain.present? && !EmojiReaction.exists?(status: status, custom_emoji: custom_emoji)
+
       emoji_reaction = EmojiReaction.create!(account: account, status: status, name: shortcode, custom_emoji: custom_emoji)
 
       status.touch # rubocop:disable Rails/SkipsModelValidations
diff --git a/spec/services/emoji_react_service_spec.rb b/spec/services/emoji_react_service_spec.rb
new file mode 100644
index 00000000000000..62d81d57c5e869
--- /dev/null
+++ b/spec/services/emoji_react_service_spec.rb
@@ -0,0 +1,139 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe EmojiReactService, type: :service do
+  subject do
+    described_class.new.call(sender, status, name)
+    EmojiReaction.where(status: status, account: sender)
+  end
+
+  let(:name) { '😀' }
+  let(:sender) { Fabricate(:user).account }
+  let(:author) { Fabricate(:user).account }
+  let(:status) { Fabricate(:status, account: author) }
+
+  it 'with a simple case' do
+    expect(subject.count).to eq 1
+    expect(subject.first.name).to eq '😀'
+    expect(subject.first.custom_emoji_id).to be_nil
+  end
+
+  context 'with name duplication on same account' do
+    before { Fabricate(:emoji_reaction, status: status, name: '😀') }
+
+    it 'react with emoji' do
+      expect(subject.count).to eq 1
+      expect(subject.first.name).to eq '😀'
+    end
+  end
+
+  context 'when multiple reactions by same account' do
+    let(:name) { '😂' }
+
+    before { Fabricate(:emoji_reaction, account: sender, status: status, name: '😀') }
+
+    it 'react with emoji' do
+      expect(subject.count).to eq 2
+      expect(subject.pluck(:name)).to contain_exactly('😀', '😂')
+    end
+  end
+
+  context 'when already reacted by other account' do
+    let(:name) { '😂' }
+
+    before { Fabricate(:emoji_reaction, status: status, name: '😀') }
+
+    it 'react with emoji' do
+      expect(subject.count).to eq 1
+      expect(subject.pluck(:name)).to contain_exactly('😂')
+    end
+  end
+
+  context 'when already reacted same emoji by other account', :tag do
+    before { Fabricate(:emoji_reaction, status: status, name: '😀') }
+
+    it 'react with emoji' do
+      expect(subject.count).to eq 1
+      expect(subject.first.name).to eq '😀'
+    end
+  end
+
+  context 'when over limit' do
+    let(:name) { '🚗' }
+
+    before do
+      Fabricate(:emoji_reaction, status: status, account: sender, name: '😀')
+      Fabricate(:emoji_reaction, status: status, account: sender, name: '😎')
+      Fabricate(:emoji_reaction, status: status, account: sender, name: '🐟')
+    end
+
+    it 'react with emoji' do
+      expect { subject.count }.to raise_error Mastodon::ValidationError
+
+      reactions = EmojiReaction.where(status: status, account: sender).pluck(:name)
+      expect(reactions.size).to eq 3
+      expect(reactions).to contain_exactly('😀', '😎', '🐟')
+    end
+  end
+
+  context 'with custom emoji of local' do
+    let(:name) { 'ohagi' }
+    let!(:custom_emoji) { Fabricate(:custom_emoji, shortcode: 'ohagi') }
+
+    it 'react with emoji' do
+      expect(subject.count).to eq 1
+      expect(subject.first.name).to eq 'ohagi'
+      expect(subject.first.custom_emoji.id).to eq custom_emoji.id
+    end
+  end
+
+  context 'with custom emoji but not existing' do
+    let(:name) { 'ohagi' }
+
+    it 'react with emoji' do
+      expect { subject.count }.to raise_error ActiveRecord::RecordInvalid
+      expect(EmojiReaction.exists?(status: status, account: sender, name: 'ohagi')).to be false
+    end
+  end
+
+  context 'with custom emoji of remote' do
+    let(:name) { 'ohagi@foo.bar' }
+    let!(:custom_emoji) { Fabricate(:custom_emoji, shortcode: 'ohagi', domain: 'foo.bar') }
+
+    before { Fabricate(:emoji_reaction, status: status, name: 'ohagi', custom_emoji: custom_emoji) }
+
+    it 'react with emoji' do
+      expect(subject.count).to eq 1
+      expect(subject.first.name).to eq 'ohagi'
+      expect(subject.first.custom_emoji.id).to eq custom_emoji.id
+    end
+  end
+
+  context 'with custom emoji of remote without existing one' do
+    let(:name) { 'ohagi@foo.bar' }
+
+    before { Fabricate(:custom_emoji, shortcode: 'ohagi', domain: 'foo.bar') }
+
+    it 'react with emoji' do
+      expect(subject.count).to eq 0
+    end
+  end
+
+  context 'with custom emoji of remote but local has same name emoji' do
+    let(:name) { 'ohagi@foo.bar' }
+    let!(:custom_emoji) { Fabricate(:custom_emoji, shortcode: 'ohagi', domain: 'foo.bar') }
+
+    before do
+      Fabricate(:custom_emoji, shortcode: 'ohagi', domain: nil)
+      Fabricate(:emoji_reaction, status: status, name: 'ohagi', custom_emoji: custom_emoji)
+    end
+
+    it 'react with emoji' do
+      expect(subject.count).to eq 1
+      expect(subject.first.name).to eq 'ohagi'
+      expect(subject.first.custom_emoji.id).to eq custom_emoji.id
+      expect(subject.first.custom_emoji.domain).to eq 'foo.bar'
+    end
+  end
+end